The Amp Garage

That extra 3 is probably just a typo.

Usually people would be asking “.003 vs .0003” (big difference) not “.003 vs .0033” (no difference).

I have some vintage Tektronix oscilloscopes that look amazing inside with all the point-to-point wiring and cable lacing. A lot of labor for sure.

What about Soldano? How the heaters are wired on an SLO flies in the face of everything posted here. So I think heater wires are not as critical as some make it out to be.

Oh trust me he’s definitely paying for my time. But this is his first tube amp ever so I’ve managed to dissuade him from the majority of the mods that he’s read about because I told him that the Princeton Reverb is a very famous and popular amplifier for a reason and I said play it and get to know i...

Yeah I’m really eager to get the amp back to check out the power supply nodes inside but once I confirm everything is correct there I shouldn’t have to deal with him anymore. I didn’t object to the 5Y3 when he told me because off the top of my head I thought well the tweed Deluxe has a 5Y3 so it sho...

I’ll run that by him when I get the amp back. I’ll report what I find once I have it in my hands again. Thanks for the help.

I agree, I wanted to be closer to the schematic voltages with the same rectifier called for on the tube chart and schematic, the 5AR4/GZ34. Trying to keep this amp ‘stock’.

Yeah I offered a GE 5U4GB I have on hand here but the owner has gone off the deep end reading comments on Reddit and YT for ideas and that’s how he decided on the 5Y3 himself.

Yeah I’ll be getting the amp back soon as the owner wants to do another mod (tone stack lift/raw switch) so I’ll have a chance to go through it again and check where all the power supply node wires are going.

The rectifier is a JJ GZ34 that came with the reissue amp. The customer has some kind of NOS or ANOS 5Y3 coming in the mail to drop the voltages.

So these are the voltages with tubes in the amp, Variac set to 120.0v. Exactly 6.3v on heater winding. V1: Pin 1: 310v Pin 3: 1.5v Pin 6: 310v Pin 8: 1.5v V2: Pin 1/6: 465v Pin 3/8: 9v V3: Pin 1: 200v Pin 3: 1.6v Pin 6: 208v Pin 8: (didn’t write this one down apparently?) V4: Pin 1: 292v Pin 3: 2.9v...

Thanks for the kind words.

The more eyes the better:

Those are very plausible explanations guys, thank you.

I’ll look through the rest of my hi-res potato pics to figure out what power supply nodes are feeding what. I took pics of the front and back of the board after wiring before installing for my records.

Interesting because I did in fact test all resistor values and check them off the list before installing as part of my QC process for every build. But you never know, I am human after all. Voltages were higher to much-higher than the schematic all across the amp, I can provide them if it would paint...

Hello, everyone. Like the title says. I handwired a ‘68 Custom Princeton Reverb reissue for a customer and they are complaining non-stop that the new handwired amp breaks up much later than the stock reissue amp did. I even gave them a NFB on-off switch. The only thing that was odd about the complet...