which 6V6 puch pull, tube rectified circuit?

[Giordano]

Hello,
I would need some help. I do build audio amps for 30 years, using tubes in the last 10. These are all for listening music at home.
Now, my daughter learns to play guitar and I want to build a good combo for her. I want something which is far better than the solid state combo, the best I can make.
I know it is different than home amp, but I would copy a few things, like
- no PCBA, use point to point wiring with component leads and pure copper wires. I have a small cnc machine to mill out Al or textile-phenol base
- I would use a copper U shaped base and textile-phenol based rail for the small components
- sure I want tube rectifier. Not solid state rectifier.
- I use single ended A at home, but with this I want push-pull.

As far as base circuit, I only know that I want 6V6 (maybe 6L6, but not EL34) based pus pull stage at the end, but that is all. I'm looking for a design I can get output transformer for.
I've looked at Fender AB763, but that is where I'm lost. On this forum and in other places, tons of circuit examples. From another thread here I found this excellent : https://robrobinette.com/Fender_Deluxe_Models.htm it helped me a lot, but still, I do not know which one to build. Sould this be a Fender replica, or something else, I do not know.

At least for now, she do not like reverb and vibrato effects at all. The more clean she likes more. I will not make much efforts to realize them inside. SHe could add pedals later if she wants to.

Can you please recommend designs with push pull 6V6/6L6 output and available output transformer? I appreciate if you comment also why.

I would have also some practical question. First I want to make the amp, play with it, than choose driver and build cabinet. But, it would be good to make the amp base chassis to fit the outer wood frame. I guess I need to select driver for that first, but on the other hand, I guess there are some usual size. Like, what is the Fender box inside diameters?
Also, do I need shielding on the input tubes? I was looking at pics and I see on some amps, and do not see on others. I guess it is parameter of different things, but in general, do you use shield on input tubes?

Can you help? I have good experience in home audio, but quite lost here.

Thanks a lot,
JG

[nickb]

I suggest the 55 5E3 Fender Deluxe for simpliticy. Use the same readily available transformers as the Reverb Deluxe.

55_(5E3)_Deluxe_Schematic.pdf

[Giordano]

Thanks, that looks really simple.
Which transformer would you recommend for this? Like Hammond 1750E ?

The only thing I'm missing is tone control, but I'm not sure how much is it needed. Maybe I will look at circuits with it, but could be I end up with this one :-)
Thanks,
JG

EDIT* oops, I just realize there is tone control. I'm looking at videos how that works.

[copperheadroads]

Hammond 290bx Power transformer & the Hammond 1760h output transformer for the 20 watt deluxe reverb type build
Hammond 290ax power transformer & hammond 1760e or 1750e output transformer for a tweed 5e3 build

[nickb]

Thanks, that looks really simple.
Which transformer would you recommend for this? Like Hammond 1750E ?

The only thing I'm missing is tone control, but I'm not sure how much is it needed. Maybe I will look at circuits with it, but could be I end up with this one :-)
Thanks,
JG

EDIT* oops, I just realize there is tone control. I'm looking at videos how that works.

The answer to that depends in part on what part of the world you live in. Update your profile with your location.

[mozz]

I would also say, 5E3. But, it is not the cleanest amp when turned up. For use in a house, it will be loud enough and still clean.

[nickb]

Hammond 290bx Power transformer & the Hammond 1760h output transformer for the 20 watt deluxe reverb type build
Hammond 290ax power transformer & hammond 1760e or 1750e output transformer for a tweed 5e3 build

For Hungary you can get these Hammond parts from https://hu.mouser.com

If you spend enough, and you will, the shipping is free.

I'd go for the deluxe reverb transformers. These will be a big expense so can reuse at a later date into a deluxe reverb or something else. The tone controls are a bit limited in the 5e3 but you can modify at a later date if need be.

[Chuck H]

There hasn't yet been any reference as to what musical genre your daughter is pursuing. The 5e3 is a good amp for many tones, but not a generic amp that could be considered useful for all genres even at a practice level. Something to understand is that guitar amps either are, or are not signal processors. Far removed from any hi fi reproduction type amplifiers. Or not, depending... My point is, knowing what sort of music your daughter wishes to play could influence any suggestions.

[frus]

You can also buy them here, maybe get a better price for some components

https://www.tube-town.net/ttstore/Tr...5_530_542.html

[Justin Thomas]

I'm with Chuck, and I'd almost argue a later version of the Deluxe might be a better option. Just because a Deluxe Reverb comes with Reverb & Tremolo doesn't mean she has to use them. There was also the Plain Old Dleluxe, that didn't come with Reverb. Or, since it's a build, you can just leave the effects out of the amp and just build either channel. If she likes clean as was indicated, well, how many threads do we read about using to get more headroom out of a 5E3?

Justin

[Giordano]

Thanks a lot for your help!

The amount of 5E3 is excellent and helps, but I do not say I can not it is must have. TO have a good quality, readable schematics is a must have for me, I can not design tube electronics. To have one with DC voltages on is very good, especially on the push pull stage because I always did before single ended class A outputs. To have a layout is good too, but not a must. It was long time ago when I built oscillators (the intention was amp :-), but I could do again, the layout reduce the risk for sure.

With all that, a very simple circuit like 5E3 is good, but not a must, if there is reason to go for something else.

She learns classical guitar, but a friend plays electric and I see here eyes that it is coming. We were on a show a few weeks ago, she was able to try different electric guitars with headphone (by the way, headphone output might be very interesting) and we were just stuck there.

So, I want to build something good, what can be used for different things. Practicing at home mainly, but to be able to use it on the stage is not useless. The main point now is to enjoy the sould of it and tasting.
If we would not deal with transformers, the best would be for now to make it in the style like my last headphone amp :


I mill out this textile phenol base for specific design, point to point wiring under it. It would be a cheap way to try out, but the problem is the transformers, output and power and the fact is that it is not for me, so it has to be boxed well. (do not worry, I never give out an unboxed proto like this headphone amp, only boxed, protected).
On the power transformer I just learned from your comments that it is available also ready made. That is excellent, because I usually specify it and get it made on toroid or EI core. Much better if I can get that too.
On the other end, I do not want to complicate it that much that a PCB would be needed. I just do not like PCBAs in tube circuits.

So, bottom line is, I like the 5E3, but I do not mind to do something more complex if I get more universal combo. I might leave out the reverb, but I might cut out the place for it.

When you speak about later version, which one? When you say later versions would give more headroom, is that because of the negative feedback?

If I choose the 1760H, does that determine to use the later version and can not the best for the 5E3 type no negative feedback amp? I see the primary impedance is different, but I do not know what difference it makes in the push pull circuit. FOr sure if possible I would choose the 1760H and make the feedback switchable. I might be biased here with hifi amps, where I prefer no feedback and I know guitar amp is different...

Regards,
JG

[Giordano]

Hello,
I made a new schematic how I would imagine an AB763 clone with no reverb.
Can you please look at that?

I realize, if this circuit is a right choice, than this thread can be redundant because there is a AB763 no reverb thread also. I might join that if I do not disturb that.

Please comment if you think it is a proper choice.

Thanks a lot,
JG

[nickb]

Hello,
I made a new schematic how I would imagine an AB763 clone with no reverb.[ATTACH=CONFIG]45397[/ATTACH]
Can you please look at that?

I realize, if this circuit is a right choice, than this thread can be redundant because there is a AB763 no reverb thread also. I might join that if I do not disturb that.

Please comment if you think it is a proper choice.

Thanks a lot,
JG

Mostly fine but you have the plates and cathodes of the 6V6's swapped

If you step away from your desire not to use silicon rectifiers, you could get pretty much the same performance at much lower cost, i.e no tube rectifier and no inductor both big $ items, if you did.

[Justin Thomas]

Yes, it really is shorted with no speaker plugged in. I don't understand all the electronic reasons why, but what I <DO> know is that it is much better than leaving it completely open circuit when no speaker is plugged in. And the purpose of those shorting or switching Jack's is to prevent that open circuit.

There are other more complex ways to protect the output transformer in case you forget plug in, but this way has worked for Fender for decades, and they don't have a reputation for blowing transformers, so... the first thing I check now, even before the Volume knob, when there's no sound from my amp is the speaker cables.

Justin

[Dave H]

I made a new schematic how I would imagine an AB763 clone with no reverb.[ATTACH=CONFIG]45397[/ATTACH]
Can you please look at that?

If you want the gain to be similar to the original you need to add the other 220k mixing resistor from the R13/C3 junction to ground. If the resistor isn't fitted the gain will be higher and C5 is redundant.

The "death" cap and switch are not need with a three prong power cord.

The bias supply is negative, C16 is the wrong polarity. I'd add a couple of 1 ohm 1% resistors in series with the power tube cathodes for setting the bias current.

There's a smoothing cap missing after R29.

Jack wiring looks OK.