The Amp Garage

Bob-I wrote: ↑Tue Sep 22, 2026 1:19 am

martin manning wrote: ↑Mon Sep 21, 2026 10:34 pm Put them in the freezer for a bit and then see if anything shows up with the condensation when you take them out. I've had some luck doing that, but not always.

Interesting…they’re in the freezer now.

The freezer trick didn’t work. No biggie.

martin manning wrote: ↑Mon Sep 21, 2026 10:34 pm Put them in the freezer for a bit and then see if anything shows up with the condensation when you take them out. I've had some luck doing that, but not always.

Interesting…they’re in the freezer now.

From what I can tell from my RCA tube book the tubes who’s heater looks to be 1 and 4 would not be a guitar amp tube. The one with 7 and 8 could be a 6sl7 or a 6sn7 I could use a 6SC7, which also has heaters on 7-8, I have a 5B4 Super on my bench now. I could compare a NOS to the existing tubes, wh...

Great suggestion…


The Westinghouse has 4 ohms between pins 1 and 4.

The Raytheon has 4 ohms between pins 7 and 8.

These tubes are most likely worthless for guitar amps. I just hate to throw anything out that might be useful.

Over the years I’ve collected random tubes. I have 2 that have no identifier other than manufacture and date code, This Raytheon looks to be a dual triode with an octal base. IMG_5261.jpeg IMG_5262.jpeg This Westinghouse may be a pentode, or not, I have no idea IMG_5263.jpeg IMG_5264.jpeg IMG_5265.j...

Stare at it long enough and you’ll see things. The jazz/rock switch was wired wrong. It’s late so I can’t test it, but I’m hoping that’s the issue.

Another frustrating couple of hours.

1) I reworked the lead dress following HADs pictures.
2) I modified coupling cap values to see if I could remove some of the muddy lows.
3) played around with bright caps on the OD, Ratio and master

I simply can’t get the OD to sound as expected.

As usual, you guys are great. I got back to work on the amp today and made a few changes. 1) I swapped the single layer cap on the mid switch for a multi layer vishay. It was a surprising improvement, but I felt it could be a tad brighter so I went from a 390pF to a 250pF and I’m very pleased with t...

Richard1001 wrote: ↑Thu Sep 10, 2026 10:53 pm Tube amp doctor sells CTS pots with true vintage audio taper. I used them in one of my amps and they work very well

Yes, I bought a few but they have the dead spot on the first few degrees of rotation. The vintage amps I’ve worked on don’t have that and the response is far better.

The ones with solid 1/4" shafts are typically used for Fender treble pots and should be fine. Thx Martin, that’s exactly what I’ve been doing up till now. Recently I refurbished 2 amps for friends, a 61 Tremolux and a 62 Bandmaster. Both had 30% taper pots (yes I measured) and really liked the way ...

martin manning wrote: ↑Mon Sep 07, 2026 7:01 pm Search for J taper. Amplified Parts and Mojo have them.

Amplified parts only has CTS…I don’t see Amy on mojo’s site.

I can only find CTS and they have a dead spot from 0 to 2. I heard that it’s because they use the same resistive strip with the switched pots.

Any leads?

Thx

What type of cap is on your mid switch? I can't tell if it is multilayer ceramic or traditional construction. The new production vishay caps sound nice and clear to me, while the blue TDK ones give a bit of pleasing distortion to the sound. YMMV You may also play with your lead dress to get closer ...

Hello everyone! I'm planning to have a new version of the boards produced soon, and I'd love your feedback. What are some things you would like changed in the boards? Are there some errors you found that I can correct in the next revision? Any comments regarding the documentation? I saw some of you...

Well, I’m delayed, I came down with pneumonia so I’m sitting in the hospital. But that gives me time to give this some more analysis. My issues with the OD tone are 2 fold. 1j the low end is thin and raspy, not fat and smooth as I expected and 2) the highs are lacking. I was thinking I was pushing t...