The Amp Garage

Hello -- That filament spec of 2.35 Amps is short of the 2.42+ Amps this el84 power tubes push, but it's a small delta and trust you'll be OK despite that. The Hammond and Amp Direct have same basic HV spec so a bit puzzled? Old school isn't always the best. .. For some reason this thread isn't sen...

For what it's worth, I actually ended up going with this one: https://shop.amppartsdirect.com/products/fender-champ-princeton-bronco-style-5w-15w-laydown-power-transformer-apd-8027h-by-heyboer-transformer-replaced-40-18027?_pos=4&_sid=b61923a03&_ss=r I chose it after reading that the Heyboer's were ...

Thanks everyone! I'll go with the one I found. The Hammond doesn't have enough voltage on the high voltage secondary and I'd rather be a little over than a little under. Plus, as sluckey asked, it also does physically fit, it's actually a perfect fit to the original holes.

Helmholtz wrote: ↑Sat May 30, 2026 10:55 pm Do you rather mean EL84s?

Oops, typo. I absolutely do, thanks.

I recently bought an old Harmony 415 in great shape. It's almost all original except for the power transformer and the 5Y3 tube was replaced with diodes. The transformer that is in it doesn't have a 5V output for the 5y3 heater and I am hoping to put the 5Y3 back in it, so I'm looking for a replacem...

You may find this helpful: https://roef.folk.ntnu.no/JTM100.html Your amp looks like it lines up with version "7B." A truly useful site, btw, Roe! Indeed, but it's even better with photos and working links http://www.amparchives.com/2019/10/12/the-evolution-of-the-100w-circuit-from-jtms-to-jmp-supe...

And thanks to everyone for all the help, I hope everybody here in the USA is having a fantastic Thanksgiving!!!

Thanks cdemike, I also noticed the V1 820R cathode capacitor is not on mine. And both channels have an 820R resistor there, not an 820 and a 2.7k like in the diagram. The other capacitor has been replaced with a 220uf instead of the 250uf. I wonder if I should find a better capacitor and replace it ...

Here are the two schematics I've found, for what it's worth. I think mine is in between these two. It would be great to find a the correct schematic if it exists.

@cdemike Wow, thanks for all the very useful info!! I've read everything you said once, but I'll have to read again carefully and understand the specifics. I was actually planning to solder the ground to the chassis. I just stuck in on the post to be able to turn the amp on and test it. It was sold ...

This should be a fun and rewarding project if you take the time to evaluate every component for proper specs and other operational integrity. I’m focusing on the trannies first. I see a choke by Classic Tone… What are the others? What’s your experience with working on amps? There’s quite a few extr...

Hello all! This is my first post here. I just got an early/mid 1969 Super Lead, at least I think, and I’d like to do the right things to make this one true to the original spirit of the amps. So, hoping I can ask some questions and learn. The amp has had some things done right, and some things done ...