Tube Amp Archive

The amp is working again. Someone had moved the NFB to the wrong tap and correcting that fix the problem.

if you post the transformer model number I can probably give you the color code for the Ohm Taps. so you can test continuity and know which contacts are what on the impedance selector. While the amp is discharged it might be a good idea to clean and tighten the tube socket pins. I'm guessing it's a...

Thanks for the tips. There are no letters visible on the selector for the impedance but the plug is connected between center to hole at 12 o clock. I forgot to tell you guys that I changed the rectifier diodes to MUR ultra fast diodes. I will compare all connections with the pictures I took before s...

I have got a Marshall JMP Super Bass 100 1969 on my bench. The amp was working but needed new filter caps and tubes. And now after that has been completed the amp is making squeeling noises when either volume knob is turned up but volume 1 sounds worse. You can turn the volume up more on the second ...

ampdoc1 wrote:If any pots are getting hot, you've got a worse problem than you think.

Typical pots in a guitar amp are handling very little power. Dirt, and old age are completely another problem!

The pots are getting hot from the all the heat rising up from the tubes.

Hello guys, I got on my bench today a reissue Marshall Bluesbreaker. When it came to me it was losing all power after it had been running for 10-20 minutes. First thing I checked was all electrolytic caps. All elytic caps tested OK. Next I replaced 3 potentiometers volume 1 and 2 and bass. The old o...

Hello Ampgarage

I am planning my next build. It is going to be a vibro king clean channel with ODS overdrive section and 3 tube fender reverb.

I don't have my ODS on hand to measure it myself. How many volts is the average B+4 in an ODS??

Hello I am overhaulin my first amp. It is a Vibroverb clone and it has a GZ34 rectifier and one of the changes I am going to do is replacing it with a solid state rectifier. The PT puts out 355-0-355 and with GZ34 it puts out a 465V B+. If I replace it with a solid state one the B+ will be 500V acco...

Here is a video of the amp in action. I am a graduating as a electronic technician in may and this amp was my final project in one class. In the video Omar Gudjonsson plays handmade guitars made by Gunnar Orn a local luthier here in Reykjavik. He is using the clean channel and some pedals but I will...

Thanks for the comments Nice looking amp! Are you running 6L6? I am running winged c 6L6. The amp is currently biased at 38mA and plates are close to 430V. Thanks for the link. What OT you have in it? OT is a Heyboer Showman/Twin. The PT is Heyboer with only 230V primary and a extra 6.3V tap to run ...

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And more...

Here are some pictures!

How hot are you guys running the power tubes. What cathode current range is recommended?

I finally finished my first ODS clone. Fired it up and everything works as it should. I need some advise from other builders on how to tune the internal trimmers for the OD entrance and phase inverter? What is the best way to get these settings right? I went for 100k plates and 1500/10uF cathodes an...

My ODS clone is finally coming together. I will post pictures when it's finished.

What tubes should I buy both for the power and preamp?

I play mostly John Mayerish type of music. The amp has 100k plates and 10uF/1500.