How many years you've been hoarding transformers that's quite a collection you got there. That will keep you busy for the next few years. It's nice to have a hobby like that it keeps your mind from going to dark places.
Thank you for explaining how the impedance ratio of the output transformer is determined. Many folks think that the transformer has impedances that determine their operating characteristics. Actually, the impedances of the windings need to be much higher than the ones they are transforming.
Your incredible knowledge and plain speaking way of explaining things makes your videos both interesting and enjoyable. I'm going to look at Part 2 now! Thanks for making the effort to recording (and editing) these videos. Regards from the UK
Wow…your shed full of goodies is insane. So much amazing stuff, but you just tend to accumulate a lot being in this line of work and / or hobby. Still cool to see someone else’s stash. Perfect example of one man’s trash….. Good layout. I personally like the 6SN7 driver. It’s a tried and true design.
Excellent video, Its going to be a classic. I like the idea of Amorphous core transformers, as the losses are the square proportion to inductor material (lack of) thickness.. They will pack a punch with the tube output stages and also probably the input power and choke stages too. An amorphous core the size of a hockey puck can do up to 8kw. Which is great, it means low inductance, low losses, magnetic punch. So it probably does better with sound quality on a magnetic transfer basis, and is lightweight, and its cheap, and its compact. The small cores for about 100w are tiny, I would use bigger than nessesary ones for the sake of rewinding and increasing the Amount of Copper. They can be easy to wind, I wish there was a book or something with the detail details in the real world. Like wire, conductors, winds, loading for common applications, starting with 120v to desired voltage, bridge rectified and center tapped. Idk if I could ever master the equations to make real instructions. The cores can be purchased cheap even on digikey, and if you bought a bunch of magnet wire, I BET one could reliably and easily wind thier own tranformers across the board. As toroids are waaay easier to wind and keep in specifiaction over the square ones. It would Only take Real instructions and about a day of doing. COOL VIDEO THANK YOU!
Love the video. I have quite a few transformers, but not as many as you. I put all my transformers in smallish plastic tubs. Seems everything around my place gets so dusty. I do live in the country though. Have to use small containers. Weight can get pretty heavy if they are too big. Have my tubes in plastic containers also. They are a little larger. I probably have close to 10k tubes. Like to see your tube collection. Will watch part 2 now. 😊
I think a primary inductance of 45 Henries will be to low for good low freq response. at very least need 100 henries for freq response down to at least 30 hz guessing at it for output transformer. That means super large output transformer. If we could just figure out how to decrease the size of the core gap for SE. Can yo do a freq test of the transformer actually hooked up to an 8 ohm speaker? I suppose the larger you go the better. A higher primary impedance results in more inductance on the primary, higher impedance better low freq response. How do you match impedance which changes with freq for transformer and amp output impedance? damping is probably better with bigger transformer also?
The Williamson amplifier was designed by David Theodore Nelson Williamson, a Scottish electronics engineer. He published the design in a series of articles in the British magazine Wireless World in 1947. During those days they believed something like 50H was necessary in an OPT but over the years that understanding has changed. Her is a real example. Assume you have a high-end OPT that measure's 20H plate to plate on the primary. That is actually a good value for a nice high-end OPT. We know the CT goes to the PS and there is an electrolytic (or otherwise) capacitor at the output of the PS. That capacitor serves two purposes - one to clean up the PS ripple and secondly to take the CT of the OPT to ground. Here is the part that may not be obvious from the typical way circuits are drawn. We know the two tubes in push-pull operate one at a time for signal and that the tube that is supplying signal is operating from one side of the OPT to the CT - not plate to plate - that means in an OPT of 20H plate to plate, it is only 5H plate to signal ground at the CT. Indeed, the tube signal portion of the tube is operating across only 5H and that is plenty sufficient for excellent bass. We have to analyze the audio circuits from two perspectives - one is the DC perspective and the other is the signal perspective. I hope I have presented this in a way that makes sense. Lastly, if 50H or 100H were necessary for good bass response, there would be so much interwinding capacitance the high frequency response would be very attenuated and vacuum tube audio would not be what it is today.
A couple of possible tube option suggestions could be 6HJ5, 6LR6, 6LW6, 6B4G or 6DQ6/6GW6. I like the compactron or sweep tubes or the lesser used tubes personally compared to the commonly used tubes, I find it more challenging and I tend to learn a lot more from the experience trying to get them to work efficiently or in some cases at all. 🙂
The 6B4G is one of my favorite tubes. I have already settled on the 807 as was suggested earlier because I have never built a SE amplifier with a beam power tube, only the 300B.
@@ElPasoTubeAmps Cool I like the 807 and 6SN7 (FU-7 and 6n8p) and have built several of those chinese SE stereo amplifiers in the past and they have always sounded nice to my ears once they had a chance to burn in a little. I can send you the schematic and see how it compares to your design? One thing has always baffled me with playing with non audio tubes for audio purposes was trying to calculate the output tube load resistance for the output transformer. DO you have a quick and easy method to calculate this?
@@TheHayruss That is a good question about plate load for tubes like horizontal output tubes and similar. I think I would just assume... that they could be compared to a close equivalent tube like a EL34, 6L6GC, KT88, etc. for plate voltage, current and bias and the load resistance would be the same (?) not sure that is true though.
I have used several line matching transformers, but I only use them for 2 to 3 watt output amplifiers. They respond well at the low power levels. I still get good bass response even at 25 milliamps idle current. also I use larger coupling capacitors than needed. That helps with bass response also. I don't build the nice amps you build. I use junk and experiment to see what I can get from it. Many of my amps use TV horizontal output tubes as finals. And I have used industrial power transformers as output transformers.
That is what makes it fun and rewarding - to use what we have. It sounds like you are making good amplifiers. I have some of those industrial transformers and they powerful and the TV horizontal output tubes are serious level tubes also and were widely used years ago in CB linear amplifiers. Thanks for your comments.
As much as I enjoy your amateur radio videos I will always be an audio guy first. Looking forward to this! Please give us the Polish transformer guy's contact info.
Re layout, IP as near as poss to the IP valve, OP as near as poss to the OPT. IP valve as far away as poss from the mains/PSU. Smoothing = CLCRC. If your using 1 6SN7 then that means no NFB, not enough gain I think. Some designs use SSRP or similar for the front end, a friend of mine has built a few SE amps & used cascaded gain stages with good results. Lastly I'd ditch the rectifier valve, horrible things, same goes for the ceramic Chinese UX5 socket, I use NOS ceramic or bakelite UX5/UX7 bases, better quality, easier to mount but a tad more expensive. Looking good so far. BTW I use Shotcut, it's free & simple to use.
Really good thoughts - Thank you - I can always plug in a SS rectifier in the tube socket but lots of people like vacuum tube rectifiers so I will go with it for now. I totally agree with the separation of the PS components as far away as possible from the signal portion of the amplifier. Thanks for your comments.
whats max power can be had with any SE tube amp? can you get 7 watts with triode SE? Doesnt it make more sense to use two smaller triodes in push - pull to get same output power? Im asking because everything is a tradeoff with amps. I found an advantage with small tube triode push pull amp where i can oversize output transformer for better sound.
I agree with all that you say. An oversized OPT will sound better - that is one of the things we have in this amplifier. Push-pull is going to give much more power than just twice the power of one tube running SE and the distortion levels (with proper NFB) are going to be much better than a SE amplifier. Going to the high-power end of tubes, assume an 833A. People claim to get 50 watts in SE configuration but the 833A in push-pull modulators at 4KV on the plate and 2700 watts of audio in class-B. Hard to compare the two. Running big tubes in SE is pretty out-there, but some try it. The OPT is the component that stops most projects. Lastly, yes, a decent 7 watts in SE can be had from a tube like the 300B and maybe something close to that with a 6550/KT88 or EL34 ? Just have to try it and find out. Thanks for your comments.
Thanks for reply. I doubt I ever will have the stuff you do. How did you come accross so much stuff? Im currently working on a 3 stage luhndal interstage coupled 300B pushpull with 6c45p 1st stage, phase splitter transformer (25 hz), to ecc 99 Push Pull to interstage driving 300B pushpull. trying to get more voltage above 350 on 300 Bs to at least 370, but a little difficult idling at 170 ma for both tubes increasing to whatever at mA at 370- 375 vdc on plates. Should be okay max plate is 100mA and 400 vdc. looking for 20-25 wattts.
@@kevinhamming4514 I have had the hobby of electronics from a kid. I got my General class amateur radio license in 1963 when I was 13 and never slowed down. I was an SWL before that and it is just something that I can completely immerse myself in. RF is a bit more challenging and also astronomy including visual and radio telescope is another passion. I sometimes joke if I am obsessed or possessed by my hobbies. Amateur radio hamfests is where I have gotten much of my radio equipment and Ebay is where I have gotten most of my audio equipment. Your 300B sounds interesting. I agree that getting the B+ up to 400 or more is a good thing. I comment often about running the quiescent current in audio amplifiers so that plate dissipation is 70-80 percent of the maximum plate dissipation and like to say that running them hot - just before they blow out of the socket - 🙂 is where we get the best performance just as you are doing. Just my thoughts but to get 20-25 watts out a pair of 300B you are going to need 450 or more for B+. You are going to have to push them really hard. Best of success.
hi, id like to know if is it normal to have clipping on positive part before negative part with a single ended amp or they are supposed comes equal in the same time on the scope.thanks
Who makes the chassis? I like the inputs on the left near the driver tube. Maybe the power switch and the light on the right hand side of the front to keep the line away from that driver. Maybe it doesn't matter on a power amp? Definitely speaker outputs on the rear to simplify wiring when you are ready to make it part of a system.
Good thoughts. I have already moved the components around putting the power transformer on the right-rear corner far away from the input. There are serious currents flowing in the chassis around the CT of the power transformer and the PS capacitors. Maybe the gain control close to the 6SN7 then the pilot light and then the AC switch on the RH side keeping everything as far away from the input as possible. With the OPT on the left rear the speaker terminals on the rear right behind it. Thanks 🙂
I buy the chassis from www.mouser.com. Here are a couple of part numbers for chassis that will get you in the ball park. Mouser search engine is not friendly in my opinion Try part numbers: 1444-24 and 1444-14103 These are reasonable sized chassis for amplifiers. They have every size so you just have to keep searching if you want something smaller or larger.
I agree push-pull would be a much better amplifier for power and low distortion but this one is too far along to change now and I am interested in how it will turn out and sound as a SE amplifier. I might be able to change one of my existing amplifiers to an 807 Williamson design. Many years ago a fellow brought me an old Heathkit (I have that model now) that ran 807 and an Acrosound transformer and I tested it. I was absolutely amazed at the frequency response of the amplifier all the way down to 20 Hz. The Acrosound TO-300 family of transformers are the very best, in my opinion.
How many years you've been hoarding transformers that's quite a collection you got there. That will keep you busy for the next few years. It's nice to have a hobby like that it keeps your mind from going to dark places.
Thanks David, I'm looking forward to this build. I like the 807 tube, so many NOS & JAN tubes floating around at bargain prices.
Get you a Camera Gimbal my friend . .. Excellent content always exciting when your videos come out
What a wonderful build, David! It is such a thrill to watch you do your magic with the transformers I wound for you.
Yes! Love that you take suggestions seriously. Thank you.
Thank you for explaining how the impedance ratio of the output transformer is determined. Many folks think that the transformer has impedances that determine their operating characteristics. Actually, the impedances of the windings need to be much higher than the ones they are transforming.
Thanks for the great video have a great day
Your incredible knowledge and plain speaking way of explaining things makes your videos both interesting and enjoyable. I'm going to look at Part 2 now! Thanks for making the effort to recording (and editing) these videos. Regards from the UK
I made an SE 807 guitar amp. I like it a great deal. Design goals for hi-fi are obviously different.
Wow…your shed full of goodies is insane. So much amazing stuff, but you just tend to accumulate a lot being in this line of work and / or hobby. Still cool to see someone else’s stash. Perfect example of one man’s trash…..
Good layout. I personally like the 6SN7 driver. It’s a tried and true design.
I am definitely a fan of the 6SN7. I also like to see other's stash and workshop on TH-cam videos. Thanks for your comments.
Excellent video, Its going to be a classic.
I like the idea of Amorphous core transformers, as the losses are the square proportion to inductor material (lack of) thickness.. They will pack a punch with the tube output stages and also probably the input power and choke stages too.
An amorphous core the size of a hockey puck can do up to 8kw. Which is great, it means low inductance, low losses, magnetic punch.
So it probably does better with sound quality on a magnetic transfer basis, and is lightweight, and its cheap, and its compact. The small cores for about 100w are tiny, I would use bigger than nessesary ones for the sake of rewinding and increasing the Amount of Copper.
They can be easy to wind, I wish there was a book or something with the detail details in the real world. Like wire, conductors, winds, loading for common applications, starting with 120v to desired voltage, bridge rectified and center tapped. Idk if I could ever master the equations to make real instructions.
The cores can be purchased cheap even on digikey, and if you bought a bunch of magnet wire, I BET one could reliably and easily wind thier own tranformers across the board. As toroids are waaay easier to wind and keep in specifiaction over the square ones. It would Only take Real instructions and about a day of doing.
COOL VIDEO THANK YOU!
Love the video. I have quite a few transformers, but not as many as you. I put all my transformers in smallish plastic tubs. Seems everything around my place gets so dusty. I do live in the country though. Have to use small containers. Weight can get pretty heavy if they are too big. Have my tubes in plastic containers also. They are a little larger. I probably have close to 10k tubes. Like to see your tube collection. Will watch part 2 now. 😊
I think a primary inductance of 45 Henries will be to low for good low freq response. at very least need 100 henries for freq response down to at least 30 hz guessing at it for output transformer. That means super large output transformer. If we could just figure out how to decrease the size of the core gap for SE. Can yo do a freq test of the transformer actually hooked up to an 8 ohm speaker? I suppose the larger you go the better. A higher primary impedance results in more inductance on the primary, higher impedance better low freq response. How do you match impedance which changes with freq for transformer and amp output impedance? damping is probably better with bigger transformer also?
The Williamson amplifier was designed by David Theodore Nelson Williamson, a Scottish electronics engineer. He published the design in a series of articles in the British magazine Wireless World in 1947. During those days they believed something like 50H was necessary in an OPT but over the years that understanding has changed. Her is a real example. Assume you have a high-end OPT that measure's 20H plate to plate on the primary. That is actually a good value for a nice high-end OPT. We know the CT goes to the PS and there is an electrolytic (or otherwise) capacitor at the output of the PS. That capacitor serves two purposes - one to clean up the PS ripple and secondly to take the CT of the OPT to ground. Here is the part that may not be obvious from the typical way circuits are drawn. We know the two tubes in push-pull operate one at a time for signal and that the tube that is supplying signal is operating from one side of the OPT to the CT - not plate to plate - that means in an OPT of 20H plate to plate, it is only 5H plate to signal ground at the CT. Indeed, the tube signal portion of the tube is operating across only 5H and that is plenty sufficient for excellent bass. We have to analyze the audio circuits from two perspectives - one is the DC perspective and the other is the signal perspective. I hope I have presented this in a way that makes sense. Lastly, if 50H or 100H were necessary for good bass response, there would be so much interwinding capacitance the high frequency response would be very attenuated and vacuum tube audio would not be what it is today.
A couple of possible tube option suggestions could be 6HJ5, 6LR6, 6LW6, 6B4G or 6DQ6/6GW6. I like the compactron or sweep tubes or the lesser used tubes personally compared to the commonly used tubes, I find it more challenging and I tend to learn a lot more from the experience trying to get them to work efficiently or in some cases at all. 🙂
The 6B4G is one of my favorite tubes. I have already settled on the 807 as was suggested earlier because I have never built a SE amplifier with a beam power tube, only the 300B.
@@ElPasoTubeAmps Cool I like the 807 and 6SN7 (FU-7 and 6n8p) and have built several of those chinese SE stereo amplifiers in the past and they have always sounded nice to my ears once they had a chance to burn in a little. I can send you the schematic and see how it compares to your design? One thing has always baffled me with playing with non audio tubes for audio purposes was trying to calculate the output tube load resistance for the output transformer. DO you have a quick and easy method to calculate this?
@@TheHayruss That is a good question about plate load for tubes like horizontal output tubes and similar. I think I would just assume... that they could be compared to a close equivalent tube like a EL34, 6L6GC, KT88, etc. for plate voltage, current and bias and the load resistance would be the same (?) not sure that is true though.
I have used several line matching transformers, but I only use them for 2 to 3 watt output amplifiers. They respond well at the low power levels. I still get good bass response even at 25 milliamps idle current. also I use larger coupling capacitors than needed. That helps with bass response also. I don't build the nice amps you build. I use junk and experiment to see what I can get from it. Many of my amps use TV horizontal output tubes as finals. And I have used industrial power transformers as output transformers.
That is what makes it fun and rewarding - to use what we have. It sounds like you are making good amplifiers. I have some of those industrial transformers and they powerful and the TV horizontal output tubes are serious level tubes also and were widely used years ago in CB linear amplifiers. Thanks for your comments.
As much as I enjoy your amateur radio videos I will always be an audio guy first. Looking forward to this!
Please give us the Polish transformer guy's contact info.
I got his permission and posted his web address and TH-cam channel in my header.
Re layout, IP as near as poss to the IP valve, OP as near as poss to the OPT. IP valve as far away as poss from the mains/PSU. Smoothing = CLCRC. If your using 1 6SN7 then that means no NFB, not enough gain I think. Some designs use SSRP or similar for the front end, a friend of mine has built a few SE amps & used cascaded gain stages with good results. Lastly I'd ditch the rectifier valve, horrible things, same goes for the ceramic Chinese UX5 socket, I use NOS ceramic or bakelite UX5/UX7 bases, better quality, easier to mount but a tad more expensive. Looking good so far. BTW I use Shotcut, it's free & simple to use.
Really good thoughts - Thank you - I can always plug in a SS rectifier in the tube socket but lots of people like vacuum tube rectifiers so I will go with it for now. I totally agree with the separation of the PS components as far away as possible from the signal portion of the amplifier. Thanks for your comments.
Thanks for pin to pin HV arc comment. Looking forward to your next video.
whats max power can be had with any SE tube amp? can you get 7 watts with triode SE? Doesnt it make more sense to use two smaller triodes in push - pull to get same output power? Im asking because everything is a tradeoff with amps. I found an advantage with small tube triode push pull amp where i can oversize output transformer for better sound.
I agree with all that you say. An oversized OPT will sound better - that is one of the things we have in this amplifier. Push-pull is going to give much more power than just twice the power of one tube running SE and the distortion levels (with proper NFB) are going to be much better than a SE amplifier.
Going to the high-power end of tubes, assume an 833A. People claim to get 50 watts in SE configuration but the 833A in push-pull modulators at 4KV on the plate and 2700 watts of audio in class-B. Hard to compare the two. Running big tubes in SE is pretty out-there, but some try it. The OPT is the component that stops most projects. Lastly, yes, a decent 7 watts in SE can be had from a tube like the 300B and maybe something close to that with a 6550/KT88 or EL34 ? Just have to try it and find out. Thanks for your comments.
Thanks for reply. I doubt I ever will have the stuff you do. How did you come accross so much stuff? Im currently working on a 3 stage luhndal interstage coupled 300B pushpull with 6c45p 1st stage, phase splitter transformer (25 hz), to ecc 99 Push Pull to interstage driving 300B pushpull. trying to get more voltage above 350 on 300 Bs to at least 370, but a little difficult idling at 170 ma for both tubes increasing to whatever at mA at 370- 375 vdc on plates. Should be okay max plate is 100mA and 400 vdc. looking for 20-25 wattts.
Sorry, just let you know the amp im working on is on a couple of posts on community section on my channel which is : Kevin Hamming.
@@kevinhamming4514 I have had the hobby of electronics from a kid. I got my General class amateur radio license in 1963 when I was 13 and never slowed down. I was an SWL before that and it is just something that I can completely immerse myself in. RF is a bit more challenging and also astronomy including visual and radio telescope is another passion. I sometimes joke if I am obsessed or possessed by my hobbies. Amateur radio hamfests is where I have gotten much of my radio equipment and Ebay is where I have gotten most of my audio equipment. Your 300B sounds interesting. I agree that getting the B+ up to 400 or more is a good thing. I comment often about running the quiescent current in audio amplifiers so that plate dissipation is 70-80 percent of the maximum plate dissipation and like to say that running them hot - just before they blow out of the socket - 🙂 is where we get the best performance just as you are doing. Just my thoughts but to get 20-25 watts out a pair of 300B you are going to need 450 or more for B+. You are going to have to push them really hard. Best of success.
hi, id like to know if is it normal to have clipping on positive part before negative part with a single ended amp or they are supposed comes equal in the same time on the scope.thanks
It will only clip on the top or the bottom . It can't clip the top and bottom of a sine wave like a push-pull amplifier.
ok thanks@@ElPasoTubeAmps
Who makes the chassis? I like the inputs on the left near the driver tube. Maybe the power switch and the light on the right hand side of the front to keep the line away from that driver. Maybe it doesn't matter on a power amp? Definitely speaker outputs on the rear to simplify wiring when you are ready to make it part of a system.
Good thoughts. I have already moved the components around putting the power transformer on the right-rear corner far away from the input. There are serious currents flowing in the chassis around the CT of the power transformer and the PS capacitors. Maybe the gain control close to the 6SN7 then the pilot light and then the AC switch on the RH side keeping everything as far away from the input as possible. With the OPT on the left rear the speaker terminals on the rear right behind it. Thanks 🙂
I buy the chassis from www.mouser.com. Here are a couple of part numbers for chassis that will get you in the ball park. Mouser search engine is not friendly in my opinion
Try part numbers: 1444-24 and 1444-14103 These are reasonable sized chassis for amplifiers. They have every size so you just have to keep searching if you want something smaller or larger.
@@ElPasoTubeAmps Thanks for that.
Hi David, will you build it be in push pull configuration? I think it would perform way better. BR from Germany. Torsten
I agree push-pull would be a much better amplifier for power and low distortion but this one is too far along to change now and I am interested in how it will turn out and sound as a SE amplifier. I might be able to change one of my existing amplifiers to an 807 Williamson design. Many years ago a fellow brought me an old Heathkit (I have that model now) that ran 807 and an Acrosound transformer and I tested it. I was absolutely amazed at the frequency response of the amplifier all the way down to 20 Hz. The Acrosound TO-300 family of transformers are the very best, in my opinion.