Well, this is a more "organic" kind of music which I prefer, but many people complained about having background music of any kind so I just stopped using music in the videos.
Hello, I have wound hundreds of thousands of coils for many different types of trannys. I have never tried to wind an output tranny and I really like your video. I recommend do not use any metal foil type of tape. This can short from turn to turn. Use P-248 made by permacel. I used to get all of these winding materials from Avnet. They have it all. In the old days they were called Brownell Electro. 3 to 5 mil kraft would work good on these wire sizes. Plain Kraft coil paper soaks up varnish and this increases the dielectric strength so no layer to layer shorts. Should use a coil varnish, air dry which takes overnight. Can bake in the oven for one hour. Coil varnish has a dielectric strength of 2000 volts one dip. Some have higher strength but air dry is enough for these voltages. Best to warm up the tranny assembled and dip into the varnish. This really sucks up the varnish and less voids. Makes it creep into all of the windings very well that way. Thanks for the video.
Thanks again for the comment. I will check the P-248 I've ordered one recently still waiting for it to be shipped. Beeswax seems to work just fine, but I would like to try the coil varnish as well, thanks for the suggestion! Are you still in the transformer making business or?
Heating coil before you dip it doesnt mean you get better varnish penetration. You have to vacuum dip it. Just ask me, I know, wound transformers for 30 years.
@@Delatsch Really great video! Always wanted to see how is the winding of OTs made and here it is:-) Seems to be easy, but is pure experience and knowledge... Wire counts and thicknesses, waxing or not, paper layers, winding layers..etc.. Wrong transformers can easily hiss etc.. Actually I found this by accident, cause my 5E3 reissue has low output and I think the reason is faulty OT. The only 5E3 seller is TAD, so I checked other possibilities and found you amazing video! Thanks again!:)
yes you are right.its very complicated when you are reading and learning about the theories of many computation in making a transformer..the best things is an actual by watching it like what you are doing now..im starting to learn now from your actual tutorial, and learning about the theory will only follows after we learn it by actual teaching.thanks for sharing your knowledge..
Exactly! Once you follow the simple steps and build an actual transformer that works you will become confident and then if there is something you don't like about that transformer or if the performance is poor in any way you will look further into the theory and try to find the solution or improvement. Most of the time in most applications simple transformers perform really well. Thank you for you kind comment and good luck with winding your transformers!
Very munch enjoyed watching the documentary on making valve output transformers. The documentary reminds me back 1980's when I worked as inspector at Express Lifts they made a lot of there transformers this method in the coil winding shop by hand.
Great vid. I am building a replica of an old Vox amp.Its original OT had an 8K input impedance with 8 & 15 Om secondary taps. The amp was originally rated as a 10W amp, but anecdotally owners of originals and its tube compliment mean it probably pushes more like 18W when driven hard. It had 1 x 12AX7 as pre-amp and tremolo, 1 x 12AU7 for second gain stage, (cathode coupled), 1 x 12AU7 for reverb drive and recovery, 1 x 12AU7 for phase inverter, 2 x EL84 output tubes cathode biased in push/pull and 1 x EZ81 rectifier. The PT was 300-0-300V giving a DC output design V of 390V before the first dropping resistor/filter stage. The B+ was around 300V. There are no specs I can find for the original English made Drake OT which had serial nos 352-98 or 352-93. A similar OT available on the market today with similar impedance are only rated for 10 or 15W. Is it possible to wind an OT with 8K in and 8&16Ohm Out that would be rated at say 20W? What is the difference between one rated at say 10W and a higher rating? I assume the winding ratios are the same to achieve the desired input vs output impedance ratio but in a higher wattage rated OT does it mean thicker gauge copper or more turns on each side or a combination of both to get an OT that can take a higher wattage output from an amp?
Thanks! I don't know about the original, but yes you can wind a transformer for any turns ratio and power (wattage) rating and much more. The power rating depends on the gauge of the wire and indirectly on the size of the core because there is a physical limit to how much wire of a certain gauge can fit to the bobbin of a give core size. Now, unless you know the exact wire gauge used in the original and the original core size the rating itself is not a 100% accurate way of knowing what they've used. The good news is that if you are in the ballpark of the original core size and close to the power rating the original used you will get a very similar sound and feel to the original. The OTs are very flexible and unless they are really "underwound" (less turns in the primary means less inductance and less low and low mid frequencies) they will not change the tone too much. In guitar amps having an undersized core and exceeding the power rating was a very common reality. Pushing the transformer over its limits can give a nice saturated tonal quality to the sound that so many people prefer. But if you would like to experiment and calculate your own output transformer you can see how the parameters and core size change with the power rating, impedance and frequency response changes you can get the PP output transformer calculation spreadsheet from my website. It is a very powerful tool and you can calculate an output transformer in a matter of minutes: www.delatsch.com/product/push-pull-output-transformer-excel-spredsheet-calculator-with-pdf-tutorial/
@@Delatsch Thanks, that is interesting. I am also trying to match the power transformer and have discovered that depending on who made the transformer, stack height varied between 2 or 1.5 inches tall with the same lamination plane area footprint of 3.15 x 3.88 inches. I understand this would effect the overall flux of the transformer. Would it also impact the prim and secondary winding resistance? I assume this would mean different sag characteristics when used in a valve rectified circuit? I think most modern EI laminations available in ready made Tx are 3.125 x 3.75" which I hope is close enough to the original. Or are the bobbin size and the leg size of the laminations more important?
Well, there are many aspects that make small differences, but if the overall dimensions are similar then the changes are not really audible. Smaller sized transformer will usually have thinner wire in order to fit the windings to the bobbin so it will have larger voltage drop due to copper losses caused by the thinner wire heating more. But, those are really subtle differences. Unless the transformer is really largely undersized or oversized it will not make any noticable difference.
@@Delatsch Hi a quick update. The original OT was wound on an EI-075 lamination (35 UK style) with a 1" stack height. It looks as though it had interleaved Prim-Sec but I don't know how many. Probably on 2-2 or 2-3 given the bobbin size and stack height. Originally 8K Prim into 8 and 15 Ohm Sec. The amp was labeled 10W but easily produces more like 17-18W when pushed. It is known for nice compressed high end when pushed into overdrive. My assumption therefore is that the OT might have been rated at 10W. Is it possible to get 15W rating on such a small footprint? Merc Mag make what they call an OT for this vintage amp and claim a 15W rating but this is arbitrary depending how it was measured, at what freq and into what type of load etc, so it is hard to tell. Certainly the few owners I know with an original amp say they run with hot, (temp) transformers. Despite this they seem to last despite being small for what the amp puts out when driven hard. Hammond do a 1760E for a Fender which looks like its on the same lamination. Its 8.5K prim though which should be OK with my project as A-A Imp is 8K for two EL84's in PP config. So 8.5L is very close. Cheers
@@allanpennington Yeah, EI75 or 25x25mm stack is enough to handle 15W if a proper wire thickness is used. Since the frequencies produced by the guitar are not constant very low bass tones the transformer will do fine. Anything in the ballpark of 8K will work just fine. Let me know how it turned out once you try it out.
Congratulations on the video, very good job, anyone can reproduce the confection of the transformer. If the goal was to teach, it was fully achieved. very good.
Hi Nino, having a secondary between two primary windings increases the frequency response. It's not crucial for guitar amps you can wind two primary sides one after the other and then wind the secondary, or wind the secondary first and then the pimary.
@@Delatsch Ok, I know why the secondary winding is in the middle bobbin, but my question was why in the video do you start the secondary winding in the middle layer and not laterally ? Fisrt layer you wind just 25 turns (the half layer) Second layer full 45 turns. Third layer 20 turns (half layer) Wy??? I would like to use only two layers totally full.
Oh I see what you mean. I guess I just wasn't paying attention because of the filming, but you are right, you can start at the beginning of the bobbin and do just couple of full layers as you said.
Edcor USA is a nice source for M6 EI laminations what other sources are people using? Please everyone share what bobbins, kraft paper, insulations, techniques, winders. Any info let's pool it together!
Love the valve tester built-in to the workbench... Happens I've just obtained one of those chinese coil winders and it seems pretty reasonably made - my only quibble is the spindle is M10 which is pretty thick and I'd have to figure out an adaptor for smaller coil formers...
Thanks! :) Yeah, you can use a piece of thick wood, drill a hole half way on the side that goes to the spindle and insert a T-nut there, and on the opposite side you can add another t nut which will fit a thinner screw.
Where can u get the core, laminated wire and transformer plates in Europe (I am in Slovenia, but can drive to Austria if I need german things) Also where did u get the wire tensioner tool while winding?
A very instructive video, but I'm a little concerned about the aluminum tape. I think a non-conductive tape would be a better choice, perhaps kapton tape. Aluminum might pick up eddy currents and have strange effects on the transformer, it's added risk of a short due to a bad spot on the wire insulation, and if one were to wrap it a full turn around the core, it could act as a large coil with a dead short across it making the transformer useless.
Thanks! I've switched to masking tape and kapton tape in the meantime (just because the materials are thinner and cheaper) but aluminum tape makes no difference what so ever. Only if you would make a full turn or a short turn as it is often called it would make any difference. Copper and aluminum tapes are commonly used as shields in premium audio transformers and sometimes several shields are used in interleaved windings without any issues. Of course as you said it shouldn't be a full turn, there should be a small gap between the ends. You can check the newer video I've recently posted about making transformers, there I go into more detail on the materials and tecniques I use now.
@@Delatsch That's interesting, I did know about shielding between windings so I'm not sure why I thought that eddy currents could be an issue. I guess it's because I've never wound my own transformers before. I'd still be nervous about allowing the windings to touch the metal tape directly, but it sounds like you've solved that with kapton tape and so on. Looking forward to checking out your other videos.
Thanks for sharing your video. It is nicely done and I like the music. I would, however never use any kind of conductive or magnetic tape in a transformer build.
Hi could you make a video explaining how to take the datasheet of a transformer and calcutale the bobbin size i'm having trouble understanding thanks for the awesome videos
so you mention in your video go to the datasheet of the transformer you want to build yes all the calculations are there but i struggle to read it correctly
Thank you for your purchase! You should delete the transformer from the list and start from scratch. First, create at least one primary and one secondary and fill in all the required data before tapping on "Calculate" button at the top.
Hi, I love your coil winding set up. Would you have a video about it. Also you seem to have a steady hand to obtain a tight winding. But would you have some idea to automatically align the wire left to right. I need to do 60 coil, 28 awg. Thanks
Hi Jacques! Thanks for your comment. I also still haven't found a simple, practical way for it. I have an idea for a simple wire guide with couple of ball bearings and adjustable wire tensioner which I could guide with a handle. It might still not be perfect, but a lot better than full manual feeding. But I guess the best way to go is to make a stepper motor winder, fully automated to be able to make perfect neat layers. You can check Craig Hollabaugh's channel, he's developing an amazing set up for a fully automated winder. It's called "Faraday Coil WInder". He's spent many hours, days and months building and testing his machine and if you follow what he is doing in his videos you will get a clear picture of the way the whole winding process is about.
Hi John, 900V is a pretty high voltage and it exceeds the rating of EL34 tubes. The EL34 tube is rated for maximum voltage of 800V. Winding an output transformer for such voltages can be dangerous and difficult. What was the output transformer mentioned in the original schematic?
I have also difficulty to get the power supply transformer. I need from a 240v (europe is 230v / 50hz generally) prim to 1x 700v 1x 620v 1x 55v and 1x 6,3 volts. And need feed 2x ECC81 4x EL34 (stereo) Only i know is a V90 code and order nr 3240 haproko. Output transformer code U90. But company not longer at business. I kan made a ring trafo but they cost a lot to made one. Then 1 find a 1x700v ring trafo usa also high cost for delivery and customs. Also the output transformer show in schematics 4, 8, 16, 30, 60 ohms output and one Line out (125/100v). The book is from 1975.
I think that would be a really demanding and expensive project. Maybe it's better to look for a similar used amplifier. I think old German amplifier Dynacord Gigant has a power and output transformer that you could use, but it is extremely heavy.
Thanks! It's really not all that difficult. It takes a bit of patience and practice, but in the end it's not more difficult nor time consuming than putting the rest of the amplifier together.
Very inspiring video. I just bought a coil winder similar to yours, but with the intend to play around with pickups. However, I'm inclined to give transformers a stab. I have been searching for places to get core materials and robbins without luck. Can you recommend a source in Europe for these materials? Thanks.
Thanks for your kind words! I'm glad I can be an inspiration! There are no companies that I know of that sell to individuals. Please contact me on my facebook page so maybe I will be able to provide you with smaller quantities off a stock I have at hand.
I need to know EI96 laminations. How do you get those. I have that exact winder but have fitted a stepper motor to it using toothed belt 6TG or what ever it is. I am in Australia, it is really hard to find bobbind and laminations.
I don't know who is supplying the lams in Australia. I am sure you can get larger quantities from China, but for small quantities I don't know. Sometimes you can find some offers on ebay, but the shipping will probably be expensive.
As for the winding part it works perfectly, but the counter is clunky and sometimes jams or turns the wrong digit, so I would prefer a similar one which has a digital counter and plugs in. I ordered mine a long time ago from eBay, but I've seen them on Amazon and other places. If you type "Coil winder" it will pop up.
@@Delatsch I think I figured it out. I was trying to order some gerbers for both the 12VDC and the 48phantom but I realized one of them was priced @ $0.00 so I removed those two items and then it let me checkout 😀 one of those two gerber items was hanging up the final step.
There is no absolute way to tell if you have an unknown transformer, since you don't have the current ratings of the windings, but if you are winding a transformer you usually chose the square root of the power to be core cross section area in cm squared. That would be for tube guitar amps. For hifi it would be larger.
Hello! Very nice work! Hey I'm concerned about the aluminum tape between the primary and secondary insulating that potion of the winding! It acts as an electromagnetic shield! Its a small area so I'm not sure what effect it has if any. Please let me know what you think! Thank you very much!!! Fantastic video!!!!!
Thank you! There is no effect because the loop is not closed and they are not electrically connected to anything, but I've stopped using it because of the comments. Now I just use stronger masking tape :) Many people were concerned. Aluminum and copper tape are used as shielding in transformers all the time. Usually they are electrically connected to ground or one side of a winding. So, they have no bad effect on the transformers.
Very useful video. I notice each new layer starts in the middle of the bobbin rather than the side. Would the foil tape interfere with the electric field and reduce radiative heat transfer?
Thank you. Yeah, while filming I was winding from the middle instead of the end, my bad. The foil does not interfere with anything in the transformer as long as it is not one full shorted turn. Foil is commonly used for noise shield between windings in audio and power transformers alike. It makes more sense to use strong masking tape than aluminum tape since it is thinner. You can check my later videos on the subject for a more practical way of winding transformers.
Just an observation- using aluminum tape can cause some undesirable tonal changes since it is a metal in proximity to the wire. I would use paper and then varnish empregnate. :)
It doesn't affect the tone in any way since it is not connected to anything, but due to loads of comments and the fact that it is thicker than masking tape I've switched to the masking tape since. :)
@@DelatschGreat idea going towards paper. It actually does affect the tone. It works the same way as insulation/dielectric around a wire, and metal is the extreme since it can store additional energy like a capacitor. This is why cloth wire sounds more detailed and dynamic than PVC and especially Teflon wire (which is very stiff and tight against the conductor). You can witness the effect sheet metal has an inch or more away from a circuit that it is not even attached to by having a Marantz or Harmon Kardon vintage receiver playing music on the bench. While listening, remove the bottom metal panel and listen for the change in compression and unveiling of the image. There is so much air, detail, punch around the instruments when the panel is removed. Any dielectric next to a conductor affects how the electrons move. The closer proximity the dielectric, the more that current flow build up and creates a bottleneck at that point. When you get used to the way a system sounds on the bench with the blanket removed, it's tough to want to put the veil back on. For this reason, when I put gear in a wood case, I'll keep the chassis/panels removed, and it greatly helps preserve the un-constrained sound.
@@ChonkTek I can assure you that using pieces of metal tape (without closing the loop) has no perceivable affect on the sound in any way. I've wound transformers both ways and there was no difference at all. In a device like the ones you mention, the metal plate closes the faraday shield around the amplifier and is grounded, so it could affect the sound in some way, but I doubt it. You can try AB blind test with someone else setting the devices with and without panels and then try to see if you can tell which is which. Also, in some audio transformer aluminium or copper tape is used as a shield, but in that case it is almost a closed loop (with a slight gap not to make short winding) and one lead is soldered to it. So it gets connected to either a ground or different taps of the primary or secondary to get the desired effect.
Air has a very low magnetic permeability, so the steel laminations "amplify" the effect of magnetic field or help transfer it better from primary to secondary and increase inductance. Winding a useful transformer without them would be practically impossible.
Great video. Thanks. Can a split style bobbin be used for winding output transformers? It seems to me that it will be much easier to isolate the primary and secondary winding on those with less isolation material required.
Thank you. Yes, split bobbin is used especially for recording gear line output transformers and interstage transformer and power output transformers. But in this case it would not work that well because we would still have to wind two sides of the primary in two separate sections and interleave because we would probably lose too much top end if we wind primaries and secondary in separate sections.
Thanks Mark! It took a lot of wire and elbow grease, but it's fun and really rewarding when you play through that amplifier and that output transformer on stage! And winding is usually the least time consuming factor when making transformers for guitar amps.
Well explained, but I have a doubt (excuse if my question is silly), with this turns ratio for a 8 ohms speaker i found the impedance will be 8000 ohms aprox. and the 5E3 expects 6600 ohms for two 6L6's. Where 's the trick? Thanks.
The 5e3 has two 6V6s in the output section. As per tube datasheet for AB1 operation of two 6V6s the nominal load impedance is 8000 ohms. There are some OTs which were wound for 6600 ohms for 5e3 to get a different effect. As always with tube guitar amps the tolerances are pretty loose and there are no strict definitions and precise values, these are just guidelines and nominal values for "typical" operation.
Thanks. I should have searched for the schematic, sorry. I'm building a 18W Dominator clone and I have a OT with a 6600 ohms impedance so should I use it instead of a 8000 ohms OT?
I just found this video, and am new to transformer construction and was wondering, is there a specific reason for putting the secondary winding in between the two halves of the primary winding?
Is this output transformer data work with el84 singles ended tube amplifiers? Can you test it after wind, any problems you phase or any changes you have done after test. Thanks for your efforts for providing this type valuable information. And there is any application for Android user. Because I live in India and android is common here. Or any chance for your application come for Android user.....
Single ended is different. I would suggest getting the Advanced SE spreadsheet calculator from my website, since it also comes with a tutorial where I explain the process and calculations. I tried making the app for android but my knowledge is too limited so I gave up. I am hoping to find a developer who would make it for android.
Hi sir. Great job, thank you!! I can see that you not use thin paper between layers for the first coil (thin wire). I want to rebuild a burned audio transformer and it has many layers of thin wire each one separated by thin paper. Is there any problem or bad effect in the audio results if I use your method? Kindest regards.
Thank you! Paper between layers is used for two reasons - to provide better insulation between layers and to make each layer the same as the previous one and exactly on top of it. The first point is not so important if using modern double coated wire and the second has a slight effect on the sound since the losses are slightly increased if the coil is not wound uniformly. In a guitar amplifier this doesn't really matter, and in general it does not mean the transformer will sound better if wound uniformly.
@@Delatsch Sir. I wil use your method, then. Thank you very much for your soon answer and for sharing your great job. Warmest regards from Chile. José.
Thanks! I get the wire locally here in Europe. It''s pretty expensive no matter where you get it from, usually it only pays off if you buy large quantities and build more transformers.
I got plenty of the winding tools on my lab, I'll try to wind this OT , Is there any wire or linkage from primary side and secondary side ? I didn't get that part
I mean Is there any wire or link between primary side and secondary side , or these are separate parts from each other . I was just trying to understand how It works kind of things , primary side goes to 2 x 6V6's and B+1 and secondary side goes to speaker output tap or speaker directly , I didn't see any link between them while your winding process on the video.
@@Delatsch Hi friend , Thanks for the info . Thanks to your educational video I did succeed on 5e3 OT , works like a charm :) But I would like to try another one with 22 watt version has a 6.6 k output. I'm reading this on the thegearpage and the other sort of forums , some of the people say that kind of mismatches could affects the sounding of the amp very well, It may push the amp so better than the 8K, how many turns should I have to wind for to reach that sound, do you have any info about that ?
Hi, Great Videos. You make it look very easy with really good explanations. What kind of Core material have you used? I can only find thick core material (0,5mm laminates thickness) here in germany, which is should not the right material for Output transformers- at least in the opinion of some transformer specialists... regards, max
Thanks Max! I've used 0,5mm laminates, they are just fine for guitar amp output transformers. Higher grade laminates make sense for high power high fidelity linear and flat reproductions of the audio signals, but for guitar amp it might not sound as sweet as a "worse" performing one. If you would like to try the higher grade core materials however, there are plenty of companies in Germany that sell them. Those are usually factories which have minimum orders and are wholesales, but I guess they should know who the distributors are for individuals. You can try contacting "Waasner", they have high grade laminations of all shapes and sizes.
Thank you! For guitar amplifiers it is not really that important to have them closely balanced. Usually, most of the vintage ones are not balanced. The common way you can make them pretty close is to make an interleaving pattern of 1/4 Primary 1/2 Secondary 1/2 Primary 1/2 Secondary 1/4 Primary. That improves the frequency response of the higher frequencies too. Bifilar winding works in some situations but has downsides also. Some things seem logical in theory but in practice don't give the end results as expected.
Hi, if you would like to calculate and wind custom transformers you can check the simple calculator spreadsheet and short tutorial on calculating and building one I have available for sale on my website. The link is in the description of this video.
Hi, my first transformer will be a transformer designed for a tube headphone amp with to secondary impedance taps, 32 and 600 ohms. And of course a experiment transformer with separate windings for each impedance.
Hi Pronoy! Calculating and winding an output transformer requires a bit more than a simple formula, but I've made a really simple tutorial and a automated spreadsheet for calculating output transformers (both PP and SE) and it's available on my website for sale as a download: www.delatsch.com/shop/ If you would like to find a free option there are several books on the subject that you can download for free, like Wolpert's Audio Transformer Design book. It is more complicated and requires you to manually calculate several aspects of the design. The good thing about the spreadsheet I've developed is that it is extremely straightforward and simple and anyone can use it easily. The price is there more as a support for me, so I can more easily continue to develop similar automatic calculators and make better videos and new projects.
Waouhh very impressive ! Good job ! I'm in Europe too, where did you find lamination and others parts to made your transformers ? Did you find them in Europe ? Cheers from France.
Hi! Thanks! Well, the problem is I don't know any place online that sells it in small quantities, so usually there are are minimum orders which are palettes and that's way to expensive. I found the laminations locally in Serbia but there is no way to order it online unfortunately.
Thanks Chris! Here in Europe I only have access to metric lams so I usually go for a slightly larger core if I don' t have the exact one on hand. So the metric EI60 is a bit smaller, and the next larger one is EI75 so I used square stack of that. Btw, followed many of your articles and unwinds on groupdiy over the years, great stuff!
This transformer can be used with 6V6 and EL84 (6BQ5). EL34 Push-Pull requires a larger transformer and thicker wire and the primary impedance is different.
Thanks for the great video. I have been thinking about winding my own PT and OTs, but haven't yet finished researching. This really helps to give a clear idea of the process. Thank you so much for uploading this! Where do you get that pressed paper (2000 V peak rating)? Or how can I search for it (what's it called)? (I'm also based in EU) Thanks!
Thanks! Check out my latest practical winding tutorial video as well. The paper is called pressed paper or "prespan". It comes in different thicknesses. I get it locally don't know where it's available from online. I would suggest Kapton tape it has really good termal and isolation properties and it's really thin. You can check it on my website: www.delatsch.com/shop/
I'm using Patreon for people who would like to support me and if someone would like to donate directly they can contact me on my facebook page for a PayPal donation.
I used to wind transformers years ago when kits were plentiful. Now, after a 25year break I have to wind another......dismayed that you can't buy kits anymore!
Im kidding ofc. Im relatively new about building transformers Im learning about 1 year now, but I didnt see until now its allowed to put aluminum foil in windings commonly for lowering losses. But you did put some foil between widings, that was unlogical to me. (and ofc aluminum is conductive) I too was making EI trafo for soldering station. I was searching videos to figure out how to invent automatic wire guiding on my coil winder its half working. (I saw long time ago video example but cant find it again, maybe is in video history) And I couldn't find anywhere cheap small lamination EI66 type like original. I have to put bigger one I have after looking every on ebay and everywhere for smaller.... its pain in the ass. Probably all because Trump China sanctions, he screwed me in just right time, ja_kass.
Why use aluminium tape? There's no advantage, only the possibility of a voltage breakdown to the tape and unnecessary primary capacitance. Rather use yellow 50um polyester tape. Also, why use masking tape. it's not rated for electrical use as far as I know.
Hi Roger, thanks for your comment! Since making this video I've switched to masking tape and Kapton tape. Masking tape is used to hold the windings together and it's easier to wind a new layer of thicker wire over it. Aluminium tape has no practical disadvantage, it can be used as a static shield as long as you don't make a full turn (short winding). The sticky aluminium tape is not conductive from the sticky side and even if would make a short it would still make no difference in the transformer. The modern enameled wire has two coats of enamel and can withstand 200 degrees C. So, if there would be any short in the transformer it would come from two copper wires or two turns which are one next to the other since there is no insulation between them. However, in practice I've never had a transformer that shorted. Decently designed transformers are very unlikely to fail in a well designed circuit. They behave like a very slow fuse that can withstand extreme overloading for couple of seconds at least.
Using aluminum foil tape is not a good idea to secure the windings, there are many types of good non conductive insulation tapes for this purpose, aluminum is a conductive material, so, may result a unwanted interference inside the coils of your transformer.
I've switched to a regular masking tape since, simply because it's thinner and cheaper. There is absolutely no interference or any other issue that can occur from using aluminum tape inside of transformer as long as you don't make a full turn and cause a short circuit.
I fear you are not getting a proper center tap. You said 2800 turns, 1400 center tap. This is incorrect. The diameter and wire length is different for the second half of the primary.
I guess you mean it will not be fully balanced and symmetrical because of the difference in voltage drop due to the wire being longer. That is correct, but it's not too much of problem in this case. Ideally you could solve it by using a split bobbin where you would have a pretty matched and balanced windings or by another a bit more complicated interleave winding arrangement with four windings where you would connect 1-4 and 2-3. That way you get almost the same resistance in windings. In most vintage amplifiers you never have balanced and matched push pull taps, capacitors and espically resistors. And just because the system is perfectly balanced doesn't mean it will sound better than the unbalanced one. Theory and practice are the same in theory but in practice they're not.
Not really sure what you mean, but there is a link in the description of this video where you can purchase the output transformer calculator spreadsheet along with the tutorial on how to wind output and power transformers.
I like your music, much better than those pages with annoying techno.
Well, this is a more "organic" kind of music which I prefer, but many people complained about having background music of any kind so I just stopped using music in the videos.
Thanks for choosing our music! Keep up the good work!
It was an easy choice! It's really difficult to find such a natural and good quality music!
Great tutorial. The more I watch these the more I want to make something.
Thank you! I encourage you to do it, it is a fun and rewarding process.
Hello,
I have wound hundreds of thousands of coils for many different types of trannys. I have never tried to wind an output tranny and I really like your video. I recommend do not use any metal foil type of tape. This can short from turn to turn. Use P-248 made by permacel. I used to get all of these winding materials from Avnet. They have it all. In the old days they were called Brownell Electro. 3 to 5 mil kraft would work good on these wire sizes. Plain Kraft coil paper soaks up varnish and this increases the dielectric strength so no layer to layer shorts. Should use a coil varnish, air dry which takes overnight. Can bake in the oven for one hour. Coil varnish has a dielectric strength of 2000 volts one dip. Some have higher strength but air dry is enough for these voltages. Best to warm up the tranny assembled and dip into the varnish. This really sucks up the varnish and less voids. Makes it creep into all of the windings very well that way. Thanks for the video.
Thanks again for the comment. I will check the P-248 I've ordered one recently still waiting for it to be shipped. Beeswax seems to work just fine, but I would like to try the coil varnish as well, thanks for the suggestion!
Are you still in the transformer making business or?
Heating coil before you dip it doesnt mean you get better varnish penetration. You have to vacuum dip it. Just ask me, I know, wound transformers for 30 years.
From commerce city colorado thanks I wound a electro dynamic speaker out of a jukebox years a go learned a lot 😮 thanks a auto stay cool from Rafael
Thank you for amazing tutorial! For many (me including) the first time to see OT winding process! Great work!!😊
Thank you very much for your kind comment! Have more on the way :)
@@Delatsch Really great video! Always wanted to see how is the winding of OTs made and here it is:-) Seems to be easy, but is pure experience and knowledge... Wire counts and thicknesses, waxing or not, paper layers, winding layers..etc.. Wrong transformers can easily hiss etc.. Actually I found this by accident, cause my 5E3 reissue has low output and I think the reason is faulty OT. The only 5E3 seller is TAD, so I checked other possibilities and found you amazing video! Thanks again!:)
yes you are right.its very complicated when you are reading and learning about the theories of many computation in making a transformer..the best things is an actual by watching it like what you are doing now..im starting to learn now from your actual tutorial, and learning about the theory will only follows after we learn it by actual teaching.thanks for sharing your knowledge..
Exactly! Once you follow the simple steps and build an actual transformer that works you will become confident and then if there is something you don't like about that transformer or if the performance is poor in any way you will look further into the theory and try to find the solution or improvement. Most of the time in most applications simple transformers perform really well. Thank you for you kind comment and good luck with winding your transformers!
Very munch enjoyed watching the documentary on making valve output transformers. The documentary reminds me back 1980's when I worked as inspector at Express Lifts they made a lot of there transformers this method in the coil winding shop by hand.
Yep, I guess it's not fun if one of those transformers fail :) Thanks for stopping by!
Great vid. I am building a replica of an old Vox amp.Its original OT had an 8K input impedance with 8 & 15 Om secondary taps. The amp was originally rated as a 10W amp, but anecdotally owners of originals and its tube compliment mean it probably pushes more like 18W when driven hard. It had 1 x 12AX7 as pre-amp and tremolo, 1 x 12AU7 for second gain stage, (cathode coupled), 1 x 12AU7 for reverb drive and recovery, 1 x 12AU7 for phase inverter, 2 x EL84 output tubes cathode biased in push/pull and 1 x EZ81 rectifier. The PT was 300-0-300V giving a DC output design V of 390V before the first dropping resistor/filter stage. The B+ was around 300V. There are no specs I can find for the original English made Drake OT which had serial nos 352-98 or 352-93. A similar OT available on the market today with similar impedance are only rated for 10 or 15W. Is it possible to wind an OT with 8K in and 8&16Ohm Out that would be rated at say 20W? What is the difference between one rated at say 10W and a higher rating? I assume the winding ratios are the same to achieve the desired input vs output impedance ratio but in a higher wattage rated OT does it mean thicker gauge copper or more turns on each side or a combination of both to get an OT that can take a higher wattage output from an amp?
Thanks! I don't know about the original, but yes you can wind a transformer for any turns ratio and power (wattage) rating and much more. The power rating depends on the gauge of the wire and indirectly on the size of the core because there is a physical limit to how much wire of a certain gauge can fit to the bobbin of a give core size. Now, unless you know the exact wire gauge used in the original and the original core size the rating itself is not a 100% accurate way of knowing what they've used. The good news is that if you are in the ballpark of the original core size and close to the power rating the original used you will get a very similar sound and feel to the original. The OTs are very flexible and unless they are really "underwound" (less turns in the primary means less inductance and less low and low mid frequencies) they will not change the tone too much. In guitar amps having an undersized core and exceeding the power rating was a very common reality. Pushing the transformer over its limits can give a nice saturated tonal quality to the sound that so many people prefer. But if you would like to experiment and calculate your own output transformer you can see how the parameters and core size change with the power rating, impedance and frequency response changes you can get the PP output transformer calculation spreadsheet from my website. It is a very powerful tool and you can calculate an output transformer in a matter of minutes:
www.delatsch.com/product/push-pull-output-transformer-excel-spredsheet-calculator-with-pdf-tutorial/
@@Delatsch Thanks, that is interesting. I am also trying to match the power transformer and have discovered that depending on who made the transformer, stack height varied between 2 or 1.5 inches tall with the same lamination plane area footprint of 3.15 x 3.88 inches. I understand this would effect the overall flux of the transformer. Would it also impact the prim and secondary winding resistance? I assume this would mean different sag characteristics when used in a valve rectified circuit? I think most modern EI laminations available in ready made Tx are 3.125 x 3.75" which I hope is close enough to the original. Or are the bobbin size and the leg size of the laminations more important?
Well, there are many aspects that make small differences, but if the overall dimensions are similar then the changes are not really audible. Smaller sized transformer will usually have thinner wire in order to fit the windings to the bobbin so it will have larger voltage drop due to copper losses caused by the thinner wire heating more. But, those are really subtle differences. Unless the transformer is really largely undersized or oversized it will not make any noticable difference.
@@Delatsch Hi a quick update. The original OT was wound on an EI-075 lamination (35 UK style) with a 1" stack height. It looks as though it had interleaved Prim-Sec but I don't know how many. Probably on 2-2 or 2-3 given the bobbin size and stack height. Originally 8K Prim into 8 and 15 Ohm Sec. The amp was labeled 10W but easily produces more like 17-18W when pushed. It is known for nice compressed high end when pushed into overdrive. My assumption therefore is that the OT might have been rated at 10W. Is it possible to get 15W rating on such a small footprint? Merc Mag make what they call an OT for this vintage amp and claim a 15W rating but this is arbitrary depending how it was measured, at what freq and into what type of load etc, so it is hard to tell. Certainly the few owners I know with an original amp say they run with hot, (temp) transformers. Despite this they seem to last despite being small for what the amp puts out when driven hard. Hammond do a 1760E for a Fender which looks like its on the same lamination. Its 8.5K prim though which should be OK with my project as A-A Imp is 8K for two EL84's in PP config. So 8.5L is very close. Cheers
@@allanpennington Yeah, EI75 or 25x25mm stack is enough to handle 15W if a proper wire thickness is used. Since the frequencies produced by the guitar are not constant very low bass tones the transformer will do fine. Anything in the ballpark of 8K will work just fine. Let me know how it turned out once you try it out.
Jason and Skip from the TAVA podcast brought me here!
Which episode? :)
what type of laminations do we have to use? is it matters? whats the suitable grade for this?
You can use any, it doesn't really matter much in this application.
Very professionally done. Greetings from sunny Jamaica.
Thank you very much!
Congratulations on the video, very good job, anyone can reproduce the confection of the transformer. If the goal was to teach, it was fully achieved. very good.
Thank you for your kind words!
For 16Ω speaker, could I just double up the secondary to 178 turns?
Hi, no it goes by the impedance ratio, so you would only need 125 turns for a 16 ohm speaker.
And you can use thinner gauge wire for 16 ohms, something like 0.5-0.6mm.
@@Delatsch thank you! That's very helpful.
What an education, loved it. So the blue wires are the 2ndary windings and yellow are the primary. Yes, I know that little.
Thank you once again! That's correct :)
Hi, wy you start the secondary winding in the middle bobbin?
Hi Nino, having a secondary between two primary windings increases the frequency response. It's not crucial for guitar amps you can wind two primary sides one after the other and then wind the secondary, or wind the secondary first and then the pimary.
@@Delatsch Ok, I know why the secondary winding is in the middle bobbin, but my question was why in the video do you start the secondary winding in the middle layer and not laterally ?
Fisrt layer you wind just 25 turns (the half layer)
Second layer full 45 turns.
Third layer 20 turns (half layer)
Wy???
I would like to use only two layers totally full.
Oh I see what you mean. I guess I just wasn't paying attention because of the filming, but you are right, you can start at the beginning of the bobbin and do just couple of full layers as you said.
You can get M6 laminates here in the States from Tempel Steel in Chicago.
Thanks for the info!
Thank you so much for this video, priceless
Thank you!
great thanks you have inspired me to make my own output transformers
Thank you for your comment! I'm happy that my video was helpful and inspiring!
Edcor USA is a nice source for M6 EI laminations what other sources are people using?
Please everyone share what bobbins, kraft paper, insulations, techniques, winders.
Any info let's pool it together!
Edcor doesn't appear to sell laminations on their website anymore. Only transformers with huge lead times.
Great prices, tho!
Love the valve tester built-in to the workbench... Happens I've just obtained one of those chinese coil winders and it seems pretty reasonably made - my only quibble is the spindle is M10 which is pretty thick and I'd have to figure out an adaptor for smaller coil formers...
Thanks! :) Yeah, you can use a piece of thick wood, drill a hole half way on the side that goes to the spindle and insert a T-nut there, and on the opposite side you can add another t nut which will fit a thinner screw.
Where can u get the core, laminated wire and transformer plates in Europe (I am in Slovenia, but can drive to Austria if I need german things)
Also where did u get the wire tensioner tool while winding?
What is the primary and secondary impedance of this transformer
thanks for this video very informative,keep up the good work, cheers from new zealand
Thank you very much for your kind words!
A very instructive video, but I'm a little concerned about the aluminum tape. I think a non-conductive tape would be a better choice, perhaps kapton tape. Aluminum might pick up eddy currents and have strange effects on the transformer, it's added risk of a short due to a bad spot on the wire insulation, and if one were to wrap it a full turn around the core, it could act as a large coil with a dead short across it making the transformer useless.
Thanks! I've switched to masking tape and kapton tape in the meantime (just because the materials are thinner and cheaper) but aluminum tape makes no difference what so ever. Only if you would make a full turn or a short turn as it is often called it would make any difference. Copper and aluminum tapes are commonly used as shields in premium audio transformers and sometimes several shields are used in interleaved windings without any issues. Of course as you said it shouldn't be a full turn, there should be a small gap between the ends. You can check the newer video I've recently posted about making transformers, there I go into more detail on the materials and tecniques I use now.
@@Delatsch That's interesting, I did know about shielding between windings so I'm not sure why I thought that eddy currents could be an issue. I guess it's because I've never wound my own transformers before. I'd still be nervous about allowing the windings to touch the metal tape directly, but it sounds like you've solved that with kapton tape and so on. Looking forward to checking out your other videos.
thanks so much for vide0 and your background music my push pull amp i convert to single ended its sounds great
Which wire gauge sizes would be used in the construction of guitar tube amp, push pull output transformers and power transformers?
Thanks.
Thanks for sharing your video. It is nicely done and I like the music. I would, however never use any kind of conductive or magnetic tape in a transformer build.
Thanks for your comment!
Hi could you make a video explaining how to take the datasheet of a transformer and calcutale the bobbin size i'm having trouble understanding thanks for the awesome videos
What exactly do you mean? You mean to find out the size of a bobbin of an existing transformer by looking at its datasheet, or?
so you mention in your video go to the datasheet of the transformer you want to build yes all the calculations are there but i struggle to read it correctly
@@dazzlenconfused I will try to address it in the next tutorial video.
@@Delatsch thank you 😊
Great demonstration
Thank you!
thank you for the video, are the transformer kits ready available ? Where to purchase?
Don't have the kits for sale, but contact me via contact page on my website and maybe I can make a kit for you.
I bought your calculator for iphone. It crashes and does not work!!! I hit calculate and it closes the amp
Thank you for your purchase! You should delete the transformer from the list and start from scratch. First, create at least one primary and one secondary and fill in all the required data before tapping on "Calculate" button at the top.
Hi, I love your coil winding set up. Would you have a video about it. Also you seem to have a steady hand to obtain a tight winding. But would you have some idea to automatically align the wire left to right. I need to do 60 coil, 28 awg. Thanks
Hi Jacques! Thanks for your comment. I also still haven't found a simple, practical way for it. I have an idea for a simple wire guide with couple of ball bearings and adjustable wire tensioner which I could guide with a handle. It might still not be perfect, but a lot better than full manual feeding. But I guess the best way to go is to make a stepper motor winder, fully automated to be able to make perfect neat layers. You can check Craig Hollabaugh's channel, he's developing an amazing set up for a fully automated winder. It's called "Faraday Coil WInder". He's spent many hours, days and months building and testing his machine and if you follow what he is doing in his videos you will get a clear picture of the way the whole winding process is about.
Such patience and attention to detail. Real crafting. Great to watch. Must be very satisfying to play through. M
Thanks! It sure is a thrill, especially when you are on the stage and you know you've built your amp, it's really an amazing feeling.
i have a schematic (80's) of a tube amp but cant find the output transformer. Its prim 900 volts and out 90 watts (8ohms) from 2 x EL34.
Hi John, 900V is a pretty high voltage and it exceeds the rating of EL34 tubes. The EL34 tube is rated for maximum voltage of 800V. Winding an output transformer for such voltages can be dangerous and difficult. What was the output transformer mentioned in the original schematic?
@@Delatsch yes, i can make a picture.
I have also difficulty to get the power supply transformer. I need from a 240v (europe is 230v / 50hz generally) prim to 1x 700v 1x 620v 1x 55v and 1x 6,3 volts. And need feed 2x ECC81 4x EL34 (stereo) Only i know is a V90 code and order nr 3240 haproko. Output transformer code U90. But company not longer at business. I kan made a ring trafo but they cost a lot to made one. Then 1 find a 1x700v ring trafo usa also high cost for delivery and customs. Also the output transformer show in schematics 4, 8, 16, 30, 60 ohms output and one Line out (125/100v). The book is from 1975.
I think that would be a really demanding and expensive project. Maybe it's better to look for a similar used amplifier. I think old German amplifier Dynacord Gigant has a power and output transformer that you could use, but it is extremely heavy.
Fascinating. But, too much work for me to endure. Thanks for this video though. It's nice to see how something this important is built.
Thanks! It's really not all that difficult. It takes a bit of patience and practice, but in the end it's not more difficult nor time consuming than putting the rest of the amplifier together.
It's probably much less expensive as well. One day I'll give it a shot.
I would strongly recommend it if you get the chance! Thanks!
Very inspiring video. I just bought a coil winder similar to yours, but with the intend to play around with pickups. However, I'm inclined to give transformers a stab. I have been searching for places to get core materials and robbins without luck. Can you recommend a source in Europe for these materials? Thanks.
Thanks for your kind words! I'm glad I can be an inspiration! There are no companies that I know of that sell to individuals. Please contact me on my facebook page so maybe I will be able to provide you with smaller quantities off a stock I have at hand.
Brilliant video. Thank you so much for taking the time to make it.
Thank you so much, I'm glad you've enjoyed it!
I need to know EI96 laminations. How do you get those. I have that exact winder but have fitted a stepper motor to it using toothed belt 6TG or what ever it is. I am in Australia, it is really hard to find bobbind and laminations.
I don't know who is supplying the lams in Australia. I am sure you can get larger quantities from China, but for small quantities I don't know. Sometimes you can find some offers on ebay, but the shipping will probably be expensive.
How do you feel about your manual coil winder? Is the quality good? Where did you purchase it?
As for the winding part it works perfectly, but the counter is clunky and sometimes jams or turns the wrong digit, so I would prefer a similar one which has a digital counter and plugs in. I ordered mine a long time ago from eBay, but I've seen them on Amazon and other places. If you type "Coil winder" it will pop up.
I tried ordering your PDFs from your website but it kept telling me no shipping method was selected... I tried everything.
Hi, I've checked the page and it works just fine. Please send the screenshot of the error you get to my facebook page.
@@Delatsch I think I figured it out. I was trying to order some gerbers for both the 12VDC and the 48phantom but I realized one of them was priced @ $0.00 so I removed those two items and then it let me checkout 😀 one of those two gerber items was hanging up the final step.
Yeah, the gerber files were not marked as virtual so that was causing the issue. I've updated it now and should be fine. Thanks!
Great video! I assume that if you were making a single ended transformer you would all the "E's"the same direction.
Yes, that's right.
Its necesary to do that on a pushpull output transformer? Or just put the laminations the regular way?
Whats the easiest way to know if a given core is large enough and has high enough rstings for tube amp audiio tranns?
There is no absolute way to tell if you have an unknown transformer, since you don't have the current ratings of the windings, but if you are winding a transformer you usually chose the square root of the power to be core cross section area in cm squared. That would be for tube guitar amps. For hifi it would be larger.
Hello! Very nice work! Hey I'm concerned about the aluminum tape between the primary and secondary insulating that potion of the winding! It acts as an electromagnetic shield! Its a small area so I'm not sure what effect it has if any. Please let me know what you think! Thank you very much!!! Fantastic video!!!!!
Thank you! There is no effect because the loop is not closed and they are not electrically connected to anything, but I've stopped using it because of the comments. Now I just use stronger masking tape :) Many people were concerned. Aluminum and copper tape are used as shielding in transformers all the time. Usually they are electrically connected to ground or one side of a winding. So, they have no bad effect on the transformers.
Hi can i ask what are the impedances on both sides? Thanks.
Hi, the primary impedance is calculated for 8K ohms and the secondary for 8 ohms.
thank you aagain, Does this transformer work for every 15-20 watt guitar amp with two 6v6 push pull configuration? like jcm800 6v6 version?
Hi, thanks. Yes, it should work for all classic PP 6V6/EL84 PP amplifiers around that wattage.
Very useful video.
I notice each new layer starts in the middle of the bobbin rather than the side.
Would the foil tape interfere with the electric field and reduce radiative heat transfer?
Thank you. Yeah, while filming I was winding from the middle instead of the end, my bad. The foil does not interfere with anything in the transformer as long as it is not one full shorted turn. Foil is commonly used for noise shield between windings in audio and power transformers alike. It makes more sense to use strong masking tape than aluminum tape since it is thinner. You can check my later videos on the subject for a more practical way of winding transformers.
Hi, would you consider selling transformer? For example such a one in video?
Sure, please contact me on my facebook page. You can find a link in the video description.
Just an observation- using aluminum tape can cause some undesirable tonal changes since it is a metal in proximity to the wire. I would use paper and then varnish empregnate. :)
It doesn't affect the tone in any way since it is not connected to anything, but due to loads of comments and the fact that it is thicker than masking tape I've switched to the masking tape since. :)
@@DelatschGreat idea going towards paper. It actually does affect the tone. It works the same way as insulation/dielectric around a wire, and metal is the extreme since it can store additional energy like a capacitor. This is why cloth wire sounds more detailed and dynamic than PVC and especially Teflon wire (which is very stiff and tight against the conductor). You can witness the effect sheet metal has an inch or more away from a circuit that it is not even attached to by having a Marantz or Harmon Kardon vintage receiver playing music on the bench. While listening, remove the bottom metal panel and listen for the change in compression and unveiling of the image. There is so much air, detail, punch around the instruments when the panel is removed. Any dielectric next to a conductor affects how the electrons move. The closer proximity the dielectric, the more that current flow build up and creates a bottleneck at that point. When you get used to the way a system sounds on the bench with the blanket removed, it's tough to want to put the veil back on. For this reason, when I put gear in a wood case, I'll keep the chassis/panels removed, and it greatly helps preserve the un-constrained sound.
@@ChonkTek I can assure you that using pieces of metal tape (without closing the loop) has no perceivable affect on the sound in any way. I've wound transformers both ways and there was no difference at all. In a device like the ones you mention, the metal plate closes the faraday shield around the amplifier and is grounded, so it could affect the sound in some way, but I doubt it. You can try AB blind test with someone else setting the devices with and without panels and then try to see if you can tell which is which. Also, in some audio transformer aluminium or copper tape is used as a shield, but in that case it is almost a closed loop (with a slight gap not to make short winding) and one lead is soldered to it. So it gets connected to either a ground or different taps of the primary or secondary to get the desired effect.
Why do u need laminations?
What if u dont use them?
Air has a very low magnetic permeability, so the steel laminations "amplify" the effect of magnetic field or help transfer it better from primary to secondary and increase inductance. Winding a useful transformer without them would be practically impossible.
Great video. Thanks. Can a split style bobbin be used for winding output transformers? It seems to me that it will be much easier to isolate the primary and secondary winding on those with less isolation material required.
Thank you. Yes, split bobbin is used especially for recording gear line output transformers and interstage transformer and power output transformers. But in this case it would not work that well because we would still have to wind two sides of the primary in two separate sections and interleave because we would probably lose too much top end if we wind primaries and secondary in separate sections.
To unravel a mystery! Exceptional video! So, how many feet of wire did that actually take?
Thanks Mark! It took a lot of wire and elbow grease, but it's fun and really rewarding when you play through that amplifier and that output transformer on stage! And winding is usually the least time consuming factor when making transformers for guitar amps.
Well explained, but I have a doubt (excuse if my question is silly), with this turns ratio for a 8 ohms speaker i found the impedance will be 8000 ohms aprox. and the 5E3 expects 6600 ohms for two 6L6's. Where 's the trick? Thanks.
The 5e3 has two 6V6s in the output section. As per tube datasheet for AB1 operation of two 6V6s the nominal load impedance is 8000 ohms. There are some OTs which were wound for 6600 ohms for 5e3 to get a different effect. As always with tube guitar amps the tolerances are pretty loose and there are no strict definitions and precise values, these are just guidelines and nominal values for "typical" operation.
Thanks. I should have searched for the schematic, sorry. I'm building a 18W Dominator clone and I have a OT with a 6600 ohms impedance so should I use it instead of a 8000 ohms OT?
Dominator uses EL84s as far as I know, so 6600 ohms is fine for it, since EL84 require around 7000 ohms nominally.
Thanks, again. I will try it!
You are welcome!
I just found this video, and am new to transformer construction and was wondering, is there a specific reason for putting the secondary winding in between the two halves of the primary winding?
It is to reduce leakage inductance and extend high frequency response.
@@Delatsch Thank you for the response
Is this output transformer data work with el84 singles ended tube amplifiers?
Can you test it after wind, any problems you phase or any changes you have done after test.
Thanks for your efforts for providing this type valuable information.
And there is any application for Android user. Because I live in India and android is common here. Or any chance for your application come for Android user.....
Single ended is different. I would suggest getting the Advanced SE spreadsheet calculator from my website, since it also comes with a tutorial where I explain the process and calculations. I tried making the app for android but my knowledge is too limited so I gave up. I am hoping to find a developer who would make it for android.
Thanks for the great information.
Thank you!
where can i buy one?
I don't have them for sale
@@Delatsch im talking about the winding tool ..where did you buy it?
@@manuelr7121 Ebay, just ty[e coil winder nz-1
what a great video! Thx
Thank you!
How hard would it be to wind two McIntosh unity coupled transformers?
It should be relatively easy. Once I finish the current projects I would like to try winding them and making that amplifier to test.
Hi sir. Great job, thank you!! I can see that you not use thin paper between layers for the first coil (thin wire). I want to rebuild a burned audio transformer and it has many layers of thin wire each one separated by thin paper. Is there any problem or bad effect in the audio results if I use your method? Kindest regards.
Thank you! Paper between layers is used for two reasons - to provide better insulation between layers and to make each layer the same as the previous one and exactly on top of it. The first point is not so important if using modern double coated wire and the second has a slight effect on the sound since the losses are slightly increased if the coil is not wound uniformly. In a guitar amplifier this doesn't really matter, and in general it does not mean the transformer will sound better if wound uniformly.
@@Delatsch Sir. I wil use your method, then. Thank you very much for your soon answer and for sharing your great job. Warmest regards from Chile. José.
is it audio output transformer?
Yes, it is audio output transformer.
nice vid. i want to try this too. do you think you can tell me where you get the wire?
Thanks! I get the wire locally here in Europe. It''s pretty expensive no matter where you get it from, usually it only pays off if you buy large quantities and build more transformers.
Awesome video, thanks!
Thank you!
I got plenty of the winding tools on my lab, I'll try to wind this OT , Is there any wire or linkage from primary side and secondary side ? I didn't get that part
What exactly do you mean by linkage?
I mean Is there any wire or link between primary side and secondary side , or these are separate parts from each other . I was just trying to understand how It works kind of things , primary side goes to 2 x 6V6's and B+1 and secondary side goes to speaker output tap or speaker directly , I didn't see any link between them while your winding process on the video.
@@constantineaudiollc7617 There is no wire between primary and secondary, they are galvanically isolated, and are only magnetically coupled.
@@Delatsch thanks for explanation . Understood , I did some googling too. I hope I can succeed on this winding process :)
@@Delatsch Hi friend , Thanks for the info . Thanks to your educational video I did succeed on 5e3 OT , works like a charm :) But I would like to try another one with 22 watt version has a 6.6 k output. I'm reading this on the thegearpage and the other sort of forums , some of the people say that kind of mismatches could affects the sounding of the amp very well, It may push the amp so better than the 8K, how many turns should I have to wind for to reach that sound, do you have any info about that ?
you are the man, do you sell your OTs?
Thanks Zixiong! I do, please contact me on my facebook page by following the link in the description.
Hi, Great Videos. You make it look very easy with really good explanations. What kind of Core material have you used? I can only find thick core material (0,5mm laminates thickness) here in germany, which is should not the right material for Output transformers- at least in the opinion of some transformer specialists... regards, max
Thanks Max! I've used 0,5mm laminates, they are just fine for guitar amp output transformers. Higher grade laminates make sense for high power high fidelity linear and flat reproductions of the audio signals, but for guitar amp it might not sound as sweet as a "worse" performing one. If you would like to try the higher grade core materials however, there are plenty of companies in Germany that sell them. Those are usually factories which have minimum orders and are wholesales, but I guess they should know who the distributors are for individuals. You can try contacting "Waasner", they have high grade laminations of all shapes and sizes.
Really like the video! Does the primary and centre tap balance out ok? I thought it was supposed to be a bi- filar winding?
Thank you! For guitar amplifiers it is not really that important to have them closely balanced. Usually, most of the vintage ones are not balanced. The common way you can make them pretty close is to make an interleaving pattern of 1/4 Primary 1/2 Secondary 1/2 Primary 1/2 Secondary 1/4 Primary. That improves the frequency response of the higher frequencies too. Bifilar winding works in some situations but has downsides also. Some things seem logical in theory but in practice don't give the end results as expected.
Thank you! Keep up the great work!!
Hi, how do i calculate the winding for a certain resistance? One example: If the primaryresistance is 5600 ohm, how many turns?
Hi, if you would like to calculate and wind custom transformers you can check the simple calculator spreadsheet and short tutorial on calculating and building one I have available for sale on my website. The link is in the description of this video.
Hi, my first transformer will be a transformer designed for a tube headphone amp with to secondary impedance taps, 32 and 600 ohms. And of course a experiment transformer with separate windings for each impedance.
Have fun with your experiment! Let me know how it worked out!
Please call output Transformer winding formula
Hi Pronoy! Calculating and winding an output transformer requires a bit
more than a simple formula, but I've made a really simple tutorial and a
automated spreadsheet for calculating output transformers (both PP and
SE) and it's available on my website for sale as a download:
www.delatsch.com/shop/
If you would like to find a free option there are several books on the
subject that you can download for free, like Wolpert's Audio Transformer
Design book. It is more complicated and requires you to manually
calculate several aspects of the design. The good thing about the
spreadsheet I've developed is that it is extremely straightforward and
simple and anyone can use it easily. The price is there more as a
support for me, so I can more easily continue to develop similar
automatic calculators and make better videos and new projects.
Waouhh very impressive ! Good job ! I'm in Europe too, where did you find lamination and others parts to made your transformers ? Did you find them in Europe ? Cheers from France.
Hi! Thanks! Well, the problem is I don't know any place online that sells it in small quantities, so usually there are are minimum orders which are palettes and that's way to expensive. I found the laminations locally in Serbia but there is no way to order it online unfortunately.
@@Delatsch Ok thanks for your answer :) i will try to find a seller in France !
Thank you for your video
Thank you!
Triad 108 and 50246 are 4200 turns #36-37 and 132 turns #21 Lam is sq stk EI 87 108 CORE IS BUTT STACKED 50246 IS LAP 2.
Thank you for your input, Chris! Where did you find the data?
groupdiy.com/index.php?topic=60266.msg764568#msg764568
groupdiy.com/index.php?topic=70589.msg900551#msg900551
Thanks Chris! Here in Europe I only have access to metric lams so I usually go for a slightly larger core if I don' t have the exact one on hand. So the metric EI60 is a bit smaller, and the next larger one is EI75 so I used square stack of that. Btw, followed many of your articles and unwinds on groupdiy over the years, great stuff!
Glad you liked them! cj
Pls give data for pp el84
Cool work, I wouldn't use aluminum tape to tape coil ends, aluminum is diamagnetic material.
There is not problem with using it as long as you don't make a full turn and create a short winding.
*no
can i use this using el34?
This transformer can be used with 6V6 and EL84 (6BQ5). EL34 Push-Pull requires a larger transformer and thicker wire and the primary impedance is different.
Thanks for the great video. I have been thinking about winding my own PT and OTs, but haven't yet finished researching. This really helps to give a clear idea of the process. Thank you so much for uploading this!
Where do you get that pressed paper (2000 V peak rating)? Or how can I search for it (what's it called)?
(I'm also based in EU)
Thanks!
Thanks! Check out my latest practical winding tutorial video as well. The paper is called pressed paper or "prespan". It comes in different thicknesses. I get it locally don't know where it's available from online. I would suggest Kapton tape it has really good termal and isolation properties and it's really thin. You can check it on my website:
www.delatsch.com/shop/
@@Delatsch Thank you so much for the info. I'll check it out!
You are welcome!
Good video!
Thank you!
Can I buy 2 bobbins off you the 25x25?.
Please write me here on my contact page at: www.delatsch.com/contact-us/
Brother cannot install of shop I make at home please formula call me
@Delatsch consider becoming a verified publisher with Brave browser for accepting donations.
I'm using Patreon for people who would like to support me and if someone would like to donate directly they can contact me on my facebook page for a PayPal donation.
Show!
I used to wind transformers years ago when kits were plentiful. Now, after a 25year break I have to wind another......dismayed that you can't buy kits anymore!
You can contact me, I might be able to help.
@@Delatsch Done.
Thanks!!
I cheer for fireworks at the end of video xD
Ok, I guess I will have to include fireworks at the end of my next video. :)
Im kidding ofc. Im relatively new about building transformers Im learning about 1 year now, but I didnt see until now its allowed to put aluminum foil in windings commonly for lowering losses. But you did put some foil between widings, that was unlogical to me. (and ofc aluminum is conductive)
I too was making EI trafo for soldering station. I was searching videos to figure out how to invent automatic wire guiding on my coil winder its half working. (I saw long time ago video example but cant find it again, maybe is in video history)
And I couldn't find anywhere cheap small lamination EI66 type like original. I have to put bigger one I have after looking every on ebay and everywhere for smaller.... its pain in the ass.
Probably all because Trump China sanctions, he screwed me in just right time, ja_kass.
Why use aluminium tape? There's no advantage, only the possibility of a voltage breakdown to the tape and unnecessary primary capacitance. Rather use yellow 50um polyester tape. Also, why use masking tape. it's not rated for electrical use as far as I know.
Hi Roger, thanks for your comment! Since making this video I've switched to masking tape and Kapton tape. Masking tape is used to hold the windings together and it's easier to wind a new layer of thicker wire over it. Aluminium tape has no practical disadvantage, it can be used as a static shield as long as you don't make a full turn (short winding). The sticky aluminium tape is not conductive from the sticky side and even if would make a short it would still make no difference in the transformer. The modern enameled wire has two coats of enamel and can withstand 200 degrees C. So, if there would be any short in the transformer it would come from two copper wires or two turns which are one next to the other since there is no insulation between them. However, in practice I've never had a transformer that shorted. Decently designed transformers are very unlikely to fail in a well designed circuit. They behave like a very slow fuse that can withstand extreme overloading for couple of seconds at least.
Using aluminum foil tape is not a good idea to secure the windings, there are many types of good non conductive insulation tapes for this purpose, aluminum is a conductive material, so, may result a unwanted interference inside the coils of your transformer.
I've switched to a regular masking tape since, simply because it's thinner and cheaper. There is absolutely no interference or any other issue that can occur from using aluminum tape inside of transformer as long as you don't make a full turn and cause a short circuit.
I fear you are not getting a proper center tap. You said 2800 turns, 1400 center tap. This is incorrect. The diameter and wire length is different for the second half of the primary.
I guess you mean it will not be fully balanced and symmetrical because of the difference in voltage drop due to the wire being longer. That is correct, but it's not too much of problem in this case. Ideally you could solve it by using a split bobbin where you would have a pretty matched and balanced windings or by another a bit more complicated interleave winding arrangement with four windings where you would connect 1-4 and 2-3. That way you get almost the same resistance in windings. In most vintage amplifiers you never have balanced and matched push pull taps, capacitors and espically resistors. And just because the system is perfectly balanced doesn't mean it will sound better than the unbalanced one. Theory and practice are the same in theory but in practice they're not.
Video ok, please no sound.
This Transformer winding formula call me
Not really sure what you mean, but there is a link in the description of this video where you can purchase the output transformer calculator spreadsheet along with the tutorial on how to wind output and power transformers.
Please....the music is higher then your voice. !!!! turn it off .
ты что брателло мотаешь всё внавал?