The Amp Garage

It is plugged in now. I also reconnected the reverb pan. I unplugged the pedal and everything is working properly now. It is a non Fender replacement pedal. Everything works with a shorted rca plug in the Tremolo jack and nothing in the reverb pedal jack. There is motorboating in the tremolo when t...

I had an issue with that one SF amp a few months ago and got a high pitched noise when adding Reverb, spend a lot of time trying to find the issue and it was the footswitch that was not properly connected, trem on reverb and reverb on trem and by doing so it create an antenna for the signal path. Fr...

I would only replace all electrolytics on the amp (filter caps, bypass caps and bias cap) then put new tubes in after a good checkup (especially power tube and PI tubes) and go from there. The stock caps you would like to replace by 150m should all be ok and great sounding so I would leave them as i...

6V6 power amp ?

Interesting how it has no extra knobs in the back to adjust the Overdrive and the separate clean mix knob like the #60 has. This looks like it would have a different preamp circuit than the #60 Cheers Guy I think most of them are unique regarding circuit topology (from the start and with tweaking f...

I think that ceramic cap is the MOV.

Trim should be in serie with a resistor acting as a variable feedback R as seen on those early ODS 4th Gen.

Screen resistors looked a little toasted too.

Looks like three of the four cathode caps have been replaced. Trimpot in the Presence/Accent circuit as well. Aaron Yes, I can see all bypass capacitors, supply capacitors, bias and relays capacitors changed, the trimpot on the OD, the .1uF 6PS on the LTPI changed to a yellow cap. There is an odd c...

A 100W with an old EV12L is a good match (quite cheap for what it is but look for a good condition one).

If you like some speaker “crunch” a Classic 80 might be an option.
I found the EV more smooth in the mids.

From my personnal experience you can use an Xacto knife and carefully remove some carbon on the inner or outer part of the track (or both) to change resistor value but it will increase doing so, not decrease. It might mess the taper, I don’t know but I usually scrap some CTS for a higher value Volum...

Now that PAB relay still makes me wonder what the point of the trimmer/1n combo is. It is permanently connected to the bass pot middle lug. It does seem to shave of high end and some (lower) mids, but especially when PAB is engaged. Anyone ever tried such circuit? Drawn as you schem I see it connec...

Guy77 wrote: ↑Fri Jun 18, 2021 4:47 pm

rootz wrote: ↑Fri Jun 18, 2021 3:53 pm Cap size over the 220k resistor on the rca connector would be another thing I’d like to know.

The cap on the 220k resistor on rca connector reads BC 222 so I imagine this is a Visay 222pf cap

I would say 2n2 for 222 and that’s a common value at that node.

Yes, Silverface amps got a 2n2 across the 220k. It does smooth out the reverb wet signal. Do you like that amp more than a JM (clean side) ? They seemed quite similar. What about the OD with pre Reverb ? You wrote about building that amp without the OD so I guess the OD is not so good. Same tonestac...

Layout looks somewhat incomplete What are you missing? I'd be very happy to hear about any issues with the layout in case there are errors in the build/circuit. Except for a few missing or wrongly placed wires, this should be the amp as it is. I tried my best to trace the whole circuit but I guess ...

Thanks for the update !

So this is a pre OD Reverb, interesting !

Hello Guy ! Voltage is quite low at that point so no worries running a 50V rated cap (there is a 4k7 resistor between the output Jack where the feedback is tapped and that point with 390R and 1uF to ground). Most Fenders didn’t use a cap and presence pot across the 47r/100r resistor. If some use a h...