Watching competent people fixing anything should give us a little insight into the challenges that we don't have to worry so much about. Maybe some,if they watch enough ,may work out that lots more `things' can be repaired rather than discarded
To state material does not have tensile strenght of steel is true as most likely those are made out of aluminium alloy, but tensile strenght is not what you’re looking for in that application. What you mean these metals, which may well be press&sinter manufactured from powder, are brittle. They are not ductile. Ductility would be great and would allow you to go plastic deformation without breaking. For technical discussion it’s important to use terms which are universially agreed and standardized.
Because splined shafts that have compressed together are so prone to breaking when you try to spread them apart again, I don't recommend that newbies try it; but an alternative that won't do any damage is to put a bit of cutoff rubber band that is slightly longer than the diameter of the shaft into the slot before pushing the knob back on. Or, drape a very thin piece of rubber band over the shaft and push the knob back on. If it doesn't work, at the very least it's not likely to cause any further damage or impede further repairs. Another possibility is to put a small dab of thin non-hardening putty on the splined shaft or in the knob, but the putty might be difficult to remove later (especially from the inside of the knob), and it has to be very thin and soft or it'll take so much force to push the knob on that you might break the pot. It sure beats using glue, however. Don't glue knobs on!
the guy that designed the amp was on Tone Talk. He said when he delivered the initial prototypes to Eddie, Eddie had some guy reverse engineer it and build a handwired one. I wonder where that amp is and how it sounds.
James has said that it sounded bad. Something about a handwired one didn't perform/interact as good as the Prototypes Eddie had built for him (prior to production launch).
As for what happened to the old transformer, I've got a guess. Output transformers have inductance as well as capacitance between the layers of windings. That forms a resonate "tank" circuit. If the output stage breaks into oscillation, that resonance can generate high voltages that will blow out the insulation on the windings. You've now got a shorted transformer that can take out the finals. That's theory, but what I can say for sure is that I have a few 1960's transistor amps (think small tape recorders) that have a push-pull output stage and output transformer. And they WILL oscillate if not loaded. The difference is since they're powered by 9V, the voltage doesn't get high enough to damage the transformer. The load boxes you talked about may not provide enough load to keep the power amp stable. Some models may work fine with some amps. But if they're not providing the same load as a speaker (which would make them run hot), they may not work with all amps.
I remember that Peavey manufactured in the late 70's or early 80's at least Bass combo amplifiers which were pure transistor amps but the output stage used OT. A friend of mine asked me to install send/return into it which I did (this happened in 1987 or 1988) and I remember that I was a bit surprised when I saw the OT when opening it. Perhaps because of that OT it sounded IMHO quite good as well when I tried it then with my 1972 Gibson SG. (BTW that Gibson was a totally wonderful guitar but I was stupid and I sold it, and I still regret selling it. But that's totally another story.)
Yeah - he marked the holes where he was going to drill, but then drilled them at the wrong spot, right? At 15:53 he makes marks to draw his center lines. Then at 16:45 he marks the spot for the mounting holes. But at 17:18 he uses the *centerline* marks instead of the *mounting hole* marks...
Suhr, Fryette, and Waza are where it is at. The UA Ox box, like Torpedo Captor, has a “simplified” low end impendance curve without a proper resonance spike.
@@lordgraga the two notes actually has a a generic speaker curve that is actually suited for most IR’s. The Waza fails on the speaker curve and Doesn’t dissipate the amps load properly. Puts a lot of strain of the output transformer from the info I’ve looked into Love the idea of the built in effects with the Waza. The speaker speaker is exactly the reason why I didn’t choose this. It’s discussed in one of Dave Friedman’s tone talks
I checked out Brad's channel and really liked it. I was really impressed with what he did to a couple of Roland JC-77's and would like to make those changes to my JC-77. So I sent him an email asking if he would share his notes. :o)
I have a 5150 Block that's been sitting in the garage for about 10 years. I fired it up the other day and there's something wrong with it for sure. I live in WY and I'm going to have to ship it somewhere or drive it to Denver to deliver it and then make another trip to pick it up. Would you be willing to look at it if I paid for shipping?
If you want to learn anything in the world learn from someone! I learning and you actual talk and what’s in your head helps. What I need to learn is troubleshooting electrical theory and in line path troubleshooting.
Not that this is the topic of the video exactly but the UA OX (and an awful lot of others including two notes) have a very skewed impedance curve, specifically in the low frequency area of the graph. It has been a point of moderate interest amongst some tech savvy folks. These curves do not match your typical speaker curve but rather resemble a bathtub shape. This can present some dangerously high resistance to the transformer at dangerously low frequencies which could lead to frying the transformer. John Suhr has talked about this on a tone talk video with dave friedman a long time ago. Suffice to say the Suhr loadboxes have been graphed and do present a correctly shaped curve to the amplifier. The fractal loadbox is another one that does it right as well. With regards to just plain attenuators there are only 2 on the market that I'm aware of as of right now that are presenting proper curves to the amplifier (scary). Aracom's unit and a unit called the a2xr from a small one man operation in sweden called masterplant (who revealed these flawed curves in most attenuators on the market and which is where i first learned of them.)
@@nikonmikon8915 So is the OX dangerous then? Will it blow my transformers? I would really love a clear answer on this. The Suhr is great but it isn't an attenuator. Which attenuators are safe? Does the Ironman II provide a proper curve?
@@dwaynedelario No the Ironman is another one that's barely "reactive", the masterplant guy posted some PDF's of his curve tracing of different products and they're abysmal. Aracom supposedly does it right, and the masterplant attenuator (obviously) does it properly as well. UA's response to people on their forums questioning this has been "how does it sound to you". I feel like this is a BS answer and avoids the issue. I know someone who was using a two notes with their Mesa Mark V and I told them about this and they switched to the Suhr and their tone changed. He said that he just accepted the awful low end, thought it was how the amp was supposed to sound... So how does it sound? probably bad. Does UA care? Not one bit. Every big name TH-camr has one in the fucking background of their videos reinforcing the false notion that their unit is good. It's not and it's expensive. Go figure....
@@nikonmikon8915 Well this is a massive bummer. I actually like the sounds I get from the app, but the attenuated signal is fairly lacking. My biggest concern is that the Ox causes one of my bias modulated tremolo amps to thump. I am guessing the bathtub curve is involved. I can't risk any transformers going down or being slowly destroyed. Guess it's time to sell the Ox. I really did NOT want to get involved with IRs. Do you have a favorite IR loader?
Four 6L6s, about the same primary impedance, “100W” rating (5150 is marketed as 120W but that’s selective measurement). And as there are no 5150 replacements from PV…
@@PsionicAudio and there it is, the wattage difference, I figured 5150's were too high... what do you mean by "selective"? And yes it's a shame what has become of Peavey.
A 100W Marshall can put out 120W+ spikes. But its output at the onset of distortion is 100W. Which do you put in the sales literature? The 5150 voltages are close to a Twin’s. And none of the overdrive is really coming from the power section in this amp.
how do I know if the power transformer is bad? my amp just has a loud hum, that's it. Something went out on it. It just hums a loud constant hum, no guitar signal.
Hey Lyle, what solder and wire do you use in tube amps? I trust your recommendation over Amazon reviews. 22 AWG? Kester? Thank you I love your channel.
Thanks very much. I mostly use Kester 60/40 .03whatever. I use different wire for different amps and different parts of circuit. You have to know the current. In general 18AWG for octal heaters, then 20AWG to preamp heaters. Almost everything else in most amps can be 22AWG. I prefer teflon coated stranded.
@@PsionicAudio I found the solder thank you 🍻. Is there a preferable brand of wire you like? Is there a maximum voltage? You are the man! Look forward to your tone talk 👍🏻
I can't wait to spam the hell out of your live-stream with witty limericks. I'll probably have just woken up and slammed 6-8 shots of espresso if you do it in the evening.
This scares me because I use a load box with my 5150 fairly often. Is there a set of specifications to look at that would indicate more safety? I use the Suhr which I have heard is totally safe and have never had an issue.
I wonder what the people who have problems are using. I'm not about to trust a cranked amp to the cheapest possible attenuator. (Full disclosure-I have a Fryette PS-2, and I have full confidence in that thing.) I also wonder when people blow up their amp with an attenuator, if they realized how hard the amp is actually working. For just about anything that's not new, I'd have a tech look over anything I intended to ride hard, just to tag any weak spots. One of the things I've learned from these kinds of videos is that if you do certain things wrong, other things can fail in an impressive (and potentially expensive) way.
@@cpfs936 all good points. I appreciate how hard my amp is working when using a load box because the fans in the load box are going nuts and the box is still getting hot despite all that airflow 😂
aliexpress molex tools are cheap like 3 dollars . Having said that the Molex connector are not a good choose when voltage is much more than 100volts to be honest off the top of my head maybe rated on a very good day to 300vdc. Ok for lite duty heaters less than 5 amps .
@@PsionicAudio Well given it a tube with a handle not so much in this case . That said there are a large number of very poor quality item on that site buyer beware. The point about that molex connector being a poor choose for the voltage in question does stand.
Is the situation today that you cannot get an OT as a spare part for a fairly new amp or is it just so that those original spare part transformers would be as poor quality as the blown original, and better option is just to upgrade to a OT made by Hammond or some other well known manufacturer? BTW, even in case of valuable vintage amps, if a transformer blows, almost nobody seems to consider trying to get the blown transformer repaired. Is it too difficult or even impossible to open the laminated core without damaging it etc.? Of course, if possible to repair it, it surely doesn't make sense economically but it would keep the amp's appearance more original. Same thing as restuffing electrolytic caps.
Like with guitar pickups, transformer rewinds are usually only economically viable if you want to preserve the originality of an amp. Think of it like making one, but needing to take the time to break one carefully, first. The latter often takes longer than the former (no pun intended).
Peavey’s parts department is just about gone. I looked for OEM replacements, all out of stock. Rewinding a transformer is a pretty big expense so the Hammond made sense. And dollars.
@@PsionicAudio Yes, in this case Hammond OT was probably a very good choise. (Except that you had to drill some extra holes. Drilling holes to chassis is something I personally love to hate.) I just quite recently tested one Hammond OT I purchased some time ago. Voltage ratio was perfectly spot on and it exceeded promised frequency response. Seems that they know what they are doing.
I'm getting ready to start ordering parts to build a Fender Champ like amplifier. Actually I intend to build the "robrob deluxe" version. I'm curious which transformers you would go with if you were doing the same?
The Champ chassis is really cramped so if that's the style of build you're going for, I would avoid transformers with extra taps you won't use because those are just extra wires you have to tape off and tuck out of the way. For example, a 'generic' Champ power transformers (like the Hammond 291AEX) will have 100V, 110V, 120V and 240V taps on the primary. Also, you don't necessarily need a PT with an HV center tap. You can make an artificial center tap with a pair of 100 Ohm resistors (this doesn't make a big difference in terms of lead dress, but there are some other advantages to the resistor method that are worth researching). Same principle applies with output transformers. Some will have taps for 4, 8, and 16 Ohm speaker loads so if you're just building the 1x8 combo, you don't need those extra wires. The point being you can order a Champ-spec transformer with all the taps you need and none of the taps you don't, and that will make your build a little easier and cleaner if such things matter to you. I really like Rob Robinette's Champ layout. Also worth looking into Doug Hoffman's layout (he's an excellent guy to buy materials and eyelet boards from as well). That said if I were going to recommend a Champ-style build to someone today, I'd recommend the 5F2 Princeton since it's 98% the same as a Champ but the larger chassis makes for an easier, cleaner looking build.
@@testing1two547 I have been in contact with Doug too. Having a heck of a time uploading the board I want. As far as chassis. This build is going into a old radio chassis and cab. There's plenty of room.
I had a speaker cable fail open to one of my cabinets. The amp was set to 8ohms and the working speakers were 16. Sounded thin and no bass response. Also was way down on volume. Luckily I stopped and didn’t burn up the transformer.
I'm starting to think this guy uses subliminal messaging to suck me in...even got me to subscribe, especially considering that I'm a modeling guy these days. Technically I still use real amps as I send my Helix (speaker modeling bypassed of course) into the power section-only of my Bad Cats. If I ever DO go back to a full-blown conventional amp rig, at least I know what to be leery of.
Michael Soldano in an interview said Peavey 5150 designer James Brown essentially ripped off his SLO-100 circuit design. Wondering how much truth there is to that statement?
Brown added a couple of non cathode bypassed gain stages instead of the fifth stage cathode follower and directly drives the tone stack like a mesa mark series. At least he had the decency to tweak the design unlike Randall Smith who just literally copied Mike's work for the dual rec.
@@Swodie_Jeetin I've read that Mike copied Randall's design & that Randall copied Mike's design. Anyone know for fact which is true? Who came up with the original design?
I don't consider it weird watching a competent tech fix things.
Watching competent people fixing anything should give us a little insight into the challenges that we don't have to worry so much about. Maybe some,if they watch enough ,may work out that lots more `things' can be repaired rather than discarded
I appreciate your commitment to the sanctity of lunch.
To state material does not have tensile strenght of steel is true as most likely those are made out of aluminium alloy, but tensile strenght is not what you’re looking for in that application. What you mean these metals, which may well be press&sinter manufactured from powder, are brittle. They are not ductile. Ductility would be great and would allow you to go plastic deformation without breaking. For technical discussion it’s important to use terms which are universially agreed and standardized.
I enjoy watching your videos for three reasons. First, the education, secondly, your professionalism, and lastly, your sense of humor. Thank you Sir.
Peavey fan here. Love yours and Brad's videos. 2 of my favorite channels.
Because splined shafts that have compressed together are so prone to breaking when you try to spread them apart again, I don't recommend that newbies try it; but an alternative that won't do any damage is to put a bit of cutoff rubber band that is slightly longer than the diameter of the shaft into the slot before pushing the knob back on. Or, drape a very thin piece of rubber band over the shaft and push the knob back on. If it doesn't work, at the very least it's not likely to cause any further damage or impede further repairs. Another possibility is to put a small dab of thin non-hardening putty on the splined shaft or in the knob, but the putty might be difficult to remove later (especially from the inside of the knob), and it has to be very thin and soft or it'll take so much force to push the knob on that you might break the pot. It sure beats using glue, however. Don't glue knobs on!
You can also make spacers out of thin plastic to hold the splines apart. It's a bit fiddly, but it works.
Never try to bend back pot-metal shafts.
Generally, aluminium and to a lesser degree, brass, are malleable enough to have success if done carefully.
the guy that designed the amp was on Tone Talk. He said when he delivered the initial prototypes to Eddie, Eddie had some guy reverse engineer it and build a handwired one. I wonder where that amp is and how it sounds.
James brown. Nice man and has made a ton of great amps and pedals. Good interview on tone talk
@@alanmcdonald6551 for sure!
I think he may have said it sounded the same.
James has said that it sounded bad. Something about a handwired one didn't perform/interact as good as the Prototypes Eddie had built for him (prior to production launch).
"Behind the knobs, a lot of loose nuts."
I am a child and laughed.
You must be British.
@@Jaggedknife11 nah, I live in new england
@@davidfuller581 huh funny. I guess i always associated knob=dick with British slang.
As for what happened to the old transformer, I've got a guess. Output transformers have inductance as well as capacitance between the layers of windings. That forms a resonate "tank" circuit. If the output stage breaks into oscillation, that resonance can generate high voltages that will blow out the insulation on the windings. You've now got a shorted transformer that can take out the finals. That's theory, but what I can say for sure is that I have a few 1960's transistor amps (think small tape recorders) that have a push-pull output stage and output transformer. And they WILL oscillate if not loaded. The difference is since they're powered by 9V, the voltage doesn't get high enough to damage the transformer. The load boxes you talked about may not provide enough load to keep the power amp stable. Some models may work fine with some amps. But if they're not providing the same load as a speaker (which would make them run hot), they may not work with all amps.
I remember that Peavey manufactured in the late 70's or early 80's at least Bass combo amplifiers which were pure transistor amps but the output stage used OT. A friend of mine asked me to install send/return into it which I did (this happened in 1987 or 1988) and I remember that I was a bit surprised when I saw the OT when opening it. Perhaps because of that OT it sounded IMHO quite good as well when I tried it then with my 1972 Gibson SG. (BTW that Gibson was a totally wonderful guitar but I was stupid and I sold it, and I still regret selling it. But that's totally another story.)
Personally enjoy learning something new...which happens everytime you post a video... Thanks for this😎👍
😎👍❤🖖
I was shouting "no!" at 17:23. Hoped you would spot it before you used the punch.
Yeah - he marked the holes where he was going to drill, but then drilled them at the wrong spot, right? At 15:53 he makes marks to draw his center lines. Then at 16:45 he marks the spot for the mounting holes. But at 17:18 he uses the *centerline* marks instead of the *mounting hole* marks...
People used to glue TV knobs on too. When glue was used for that it held on better than it did on anything else.
Suhr, Fryette, and Waza are where it is at. The UA Ox box, like Torpedo Captor, has a “simplified” low end impendance curve without a proper resonance spike.
The Waza is actually the worst. Suhr, two notes and fryette are better options!
@@evh1eddie1rocks what’s with Waza? Also, two notes fails on the impedance curve.
@@lordgraga the two notes actually has a a generic speaker curve that is actually suited for most IR’s.
The Waza fails on the speaker curve and Doesn’t dissipate the amps load properly. Puts a lot of strain of the output transformer from the info I’ve looked into
Love the idea of the built in effects with the Waza. The speaker speaker is exactly the reason why I didn’t choose this. It’s discussed in one of Dave Friedman’s tone talks
There is little more informative or entertaining than watchimg a learned craftsman ply his trade.
I checked out Brad's channel and really liked it. I was really impressed with what he did to a couple of Roland JC-77's and would like to make those changes to my JC-77. So I sent him an email asking if he would share his notes. :o)
I'm just here to learn best practices, and thankful for the good example to follow
“Behind the knobs are a lot of loose nuts” sounds like the British aristocracy!
More like the Trump family
@@gingercat777 Brainwashed.
I have a 5150 Block that's been sitting in the garage for about 10 years. I fired it up the other day and there's something wrong with it for sure. I live in WY and I'm going to have to ship it somewhere or drive it to Denver to deliver it and then make another trip to pick it up. Would you be willing to look at it if I paid for shipping?
Thank you for your videos! Do you think the 5150's benefit from a choke instead of the dropping resistor in the power supply?
Oooh a livestream, nice! a Q&A livestream in the future would be a good idea, if you could manage.
If you want to learn anything in the world learn from someone! I learning and you actual talk and what’s in your head helps. What I need to learn is troubleshooting electrical theory and in line path troubleshooting.
Well heck,,, I love watching other people work.
Not that this is the topic of the video exactly but the UA OX (and an awful lot of others including two notes) have a very skewed impedance curve, specifically in the low frequency area of the graph. It has been a point of moderate interest amongst some tech savvy folks. These curves do not match your typical speaker curve but rather resemble a bathtub shape. This can present some dangerously high resistance to the transformer at dangerously low frequencies which could lead to frying the transformer. John Suhr has talked about this on a tone talk video with dave friedman a long time ago. Suffice to say the Suhr loadboxes have been graphed and do present a correctly shaped curve to the amplifier. The fractal loadbox is another one that does it right as well. With regards to just plain attenuators there are only 2 on the market that I'm aware of as of right now that are presenting proper curves to the amplifier (scary). Aracom's unit and a unit called the a2xr from a small one man operation in sweden called masterplant (who revealed these flawed curves in most attenuators on the market and which is where i first learned of them.)
If I were to get one I’d get the Suhr.
@@PsionicAudio A competent choice indeed
@@nikonmikon8915 So is the OX dangerous then? Will it blow my transformers? I would really love a clear answer on this. The Suhr is great but it isn't an attenuator. Which attenuators are safe? Does the Ironman II provide a proper curve?
@@dwaynedelario No the Ironman is another one that's barely "reactive", the masterplant guy posted some PDF's of his curve tracing of different products and they're abysmal. Aracom supposedly does it right, and the masterplant attenuator (obviously) does it properly as well. UA's response to people on their forums questioning this has been "how does it sound to you". I feel like this is a BS answer and avoids the issue. I know someone who was using a two notes with their Mesa Mark V and I told them about this and they switched to the Suhr and their tone changed. He said that he just accepted the awful low end, thought it was how the amp was supposed to sound... So how does it sound? probably bad. Does UA care? Not one bit. Every big name TH-camr has one in the fucking background of their videos reinforcing the false notion that their unit is good. It's not and it's expensive. Go figure....
@@nikonmikon8915 Well this is a massive bummer. I actually like the sounds I get from the app, but the attenuated signal is fairly lacking. My biggest concern is that the Ox causes one of my bias modulated tremolo amps to thump. I am guessing the bathtub curve is involved. I can't risk any transformers going down or being slowly destroyed. Guess it's time to sell the Ox. I really did NOT want to get involved with IRs. Do you have a favorite IR loader?
It’s not weird at all…. Regular tv … that s*** is weird lol. Thanks for these videos. Love’em!
Love your channel, Lyle. Not at all doubting you here, but I had no idea that Twin Reverb iron would work with a 5150.
Four 6L6s, about the same primary impedance, “100W” rating (5150 is marketed as 120W but that’s selective measurement). And as there are no 5150 replacements from PV…
@@PsionicAudio and there it is, the wattage difference, I figured 5150's were too high... what do you mean by "selective"? And yes it's a shame what has become of Peavey.
A 100W Marshall can put out 120W+ spikes. But its output at the onset of distortion is 100W. Which do you put in the sales literature?
The 5150 voltages are close to a Twin’s. And none of the overdrive is really coming from the power section in this amp.
@@PsionicAudio Got it, thanks much. I was thinking maybe Peavey based it on that
I emailed them a few months back and asked them about this exact transformer for a 6505+ and they recommended not to use this one. 🤷♂️
any experience with the evh fender built amps? supposedly better build quality?
Could you not make new brackets that support the new transformer but attach through the old holes?
Yes, at a high cost to the owner.
Really informative. Thanks for sharing!
how do I know if the power transformer is bad? my amp just has a loud hum, that's it. Something went out on it. It just hums a loud constant hum, no guitar signal.
Yeah BOI!
You were jealous of me needing to clean grease from & retention every ribbon connector?
That part was a drag. Just jealous of how the connectors easily slid off.
Hey Lyle, what solder and wire do you use in tube amps? I trust your recommendation over Amazon reviews. 22 AWG? Kester? Thank you I love your channel.
Thanks very much. I mostly use Kester 60/40 .03whatever. I use different wire for different amps and different parts of circuit. You have to know the current. In general 18AWG for octal heaters, then 20AWG to preamp heaters. Almost everything else in most amps can be 22AWG. I prefer teflon coated stranded.
@@PsionicAudio I found the solder thank you 🍻. Is there a preferable brand of wire you like? Is there a maximum voltage? You are the man! Look forward to your tone talk 👍🏻
Thanks. If you’re just starting out, tubedepot.com has a good selection of teflon coated wire.
@@PsionicAudio It's great stuff, but a little slick to cut for newbs.
I can't wait to spam the hell out of your live-stream with witty limericks.
I'll probably have just woken up and slammed 6-8 shots of espresso if you do it in the evening.
Your witty or actual witty?
@@PsionicAudio There once was a man with angina.....
This scares me because I use a load box with my 5150 fairly often. Is there a set of specifications to look at that would indicate more safety? I use the Suhr which I have heard is totally safe and have never had an issue.
I trust John.
I wonder what the people who have problems are using. I'm not about to trust a cranked amp to the cheapest possible attenuator. (Full disclosure-I have a Fryette PS-2, and I have full confidence in that thing.) I also wonder when people blow up their amp with an attenuator, if they realized how hard the amp is actually working. For just about anything that's not new, I'd have a tech look over anything I intended to ride hard, just to tag any weak spots. One of the things I've learned from these kinds of videos is that if you do certain things wrong, other things can fail in an impressive (and potentially expensive) way.
@@cpfs936 all good points. I appreciate how hard my amp is working when using a load box because the fans in the load box are going nuts and the box is still getting hot despite all that airflow 😂
aliexpress molex tools are cheap like 3 dollars . Having said that the Molex connector are not a good choose when voltage is much more than 100volts to be honest off the top of my head maybe rated on a very good day to 300vdc. Ok for lite duty heaters less than 5 amps .
Well, ones worth having are expensive. I don’t buy anything from that site.
@@PsionicAudio Well given it a tube with a handle not so much in this case . That said there are a large number of very poor quality item on that site buyer beware. The point about that molex connector being a poor choose for the voltage in question does stand.
Is there much need to isolate the the power transformer from the chassis? Like using rubber grommets to isolate it from vibration?
The title should have been " 5150 $$$$$$ transformer replacement
Is the situation today that you cannot get an OT as a spare part for a fairly new amp or is it just so that those original spare part transformers would be as poor quality as the blown original, and better option is just to upgrade to a OT made by Hammond or some other well known manufacturer?
BTW, even in case of valuable vintage amps, if a transformer blows, almost nobody seems to consider trying to get the blown transformer repaired. Is it too difficult or even impossible to open the laminated core without damaging it etc.? Of course, if possible to repair it, it surely doesn't make sense economically but it would keep the amp's appearance more original. Same thing as restuffing electrolytic caps.
I think you can get transformers rewound, but I'll bet it ain't cheap to have it done right!
Like with guitar pickups, transformer rewinds are usually only economically viable if you want to preserve the originality of an amp.
Think of it like making one, but needing to take the time to break one carefully, first.
The latter often takes longer than the former (no pun intended).
Peavey’s parts department is just about gone. I looked for OEM replacements, all out of stock. Rewinding a transformer is a pretty big expense so the Hammond made sense. And dollars.
@@PsionicAudio Yes, in this case Hammond OT was probably a very good choise. (Except that you had to drill some extra holes. Drilling holes to chassis is something I personally love to hate.) I just quite recently tested one Hammond OT I purchased some time ago. Voltage ratio was perfectly spot on and it exceeded promised frequency response. Seems that they know what they are doing.
I'm getting ready to start ordering parts to build a Fender Champ like amplifier. Actually I intend to build the "robrob deluxe" version. I'm curious which transformers you would go with if you were doing the same?
fwiw, i just built the deluxe micro off there, used hammond stuff from mouser.
The Champ chassis is really cramped so if that's the style of build you're going for, I would avoid transformers with extra taps you won't use because those are just extra wires you have to tape off and tuck out of the way. For example, a 'generic' Champ power transformers (like the Hammond 291AEX) will have 100V, 110V, 120V and 240V taps on the primary. Also, you don't necessarily need a PT with an HV center tap. You can make an artificial center tap with a pair of 100 Ohm resistors (this doesn't make a big difference in terms of lead dress, but there are some other advantages to the resistor method that are worth researching). Same principle applies with output transformers. Some will have taps for 4, 8, and 16 Ohm speaker loads so if you're just building the 1x8 combo, you don't need those extra wires. The point being you can order a Champ-spec transformer with all the taps you need and none of the taps you don't, and that will make your build a little easier and cleaner if such things matter to you.
I really like Rob Robinette's Champ layout. Also worth looking into Doug Hoffman's layout (he's an excellent guy to buy materials and eyelet boards from as well). That said if I were going to recommend a Champ-style build to someone today, I'd recommend the 5F2 Princeton since it's 98% the same as a Champ but the larger chassis makes for an easier, cleaner looking build.
@@testing1two547 I have been in contact with Doug too. Having a heck of a time uploading the board I want.
As far as chassis. This build is going into a old radio chassis and cab. There's plenty of room.
Are there any 'signs' to check when using improper load boxes or impedance mismatches?
Thanx in advance master Lyle
I had a speaker cable fail open to one of my cabinets. The amp was set to 8ohms and the working speakers were 16. Sounded thin and no bass response. Also was way down on volume. Luckily I stopped and didn’t burn up the transformer.
Do the live stream after 6pm ET if possible please.
Any other requests? Want us to order you some UberEats? You allergic to peanuts or anything?
@@BradsGuitarGarage lol cunny funt Brad
It's not weird at all for me. It feels like I'm in a classroom
Uncle Doug was the first of these channels I discovered. It's not surprising that he used to be a teacher. I'll bet he was a good one!
@@cpfs936 yes I subbed that channel years ago. Uncle Doug is fantastic
I'm starting to think this guy uses subliminal messaging to suck me in...even got me to subscribe, especially considering that I'm a modeling guy these days. Technically I still use real amps as I send my Helix (speaker modeling bypassed of course) into the power section-only of my Bad Cats. If I ever DO go back to a full-blown conventional amp rig, at least I know what to be leery of.
Michael Soldano in an interview said Peavey 5150 designer James Brown essentially ripped off his SLO-100 circuit design. Wondering how much truth there is to that statement?
Brown added a couple of non cathode bypassed gain stages instead of the fifth stage cathode follower and directly drives the tone stack like a mesa mark series. At least he had the decency to tweak the design unlike Randall Smith who just literally copied Mike's work for the dual rec.
@@Swodie_Jeetin I've read that Mike copied Randall's design & that Randall copied Mike's design. Anyone know for fact which is true? Who came up with the original design?
@@scotthowe1972 Neither of those amps sound the same.