Tube Amp Archive

help us here and add the schematic you are using to your post. The schematic has all the answers in a more readable form.

Hi, help us by posting the schematic you are using. If the schematic looks like what I could find https://el34world.com/Forum/index.php?action=dlattach;topic=23362.0;attach=71353;image , the problem might be the additional two triode stages that are added to the circuit in the OD mode. When the swit...

maxkracht wrote: ↑Thu Jul 25, 2024 8:22 pm https://www.valvewizard.co.uk/Triodes_a ... encowe.pdf

That is a nice article about using tubes at low voltages. To think that the valvecaster did something like this so long ago.

nice one! where do you got that chassis from?

About the tremolo could be a missing ground on a capacitor or resistor in the tremolo circuit.
My guess is that It works while charging and then stops unable to discharge the capacitor to continue oscillating.

Hi, finished my last build inspired in the schematic of Doug over http://www.dougcircuits.com/neon.html It also has a tremolo, but opamp based. The neon lamp wasn't working properly. I'm using a greenback 10" speaker in this small cab, which used to have a transistor amp with two 6" speakers. The sc...

Very Nice RJ, haven't seen it, but I had a similar problem, but it was due to blocking distortion.
That's why I added the last 100k leak resistor before the PCL82.
This small amps are too sensitive for gainy preamps. With the extra triode of the PCF802 there is even more gain on tap.

Hi, just finished a new small amplifier with some TV tubes I had laying around. Both the PCL82 and the PCF802 have odd filament voltages, 16v and 9v respectively, but as they require the same current I'm using them in series from a 24-0-24v transformer. This way I could also use the 48v in a simple ...

there is a long thread about the 1w marshall amps, someone just added some mods.

there are some layouts, but that looks like an exact copy of the original pcb

The graphics I printed on a transparency, and glued it on the chassis. After some layers of clear coat everything came together.

Solidworks has some extra settings for perspective view, I guess I need to learn more how about rendering to improve that.

Hi, I finished my last build, of a mini amplifier, but this time with a proper guitar speaker. Since I was going small the jensen 6" was my choice. On the way I added a meter on the front just to add some nice vintage measurement instrument look. Made some solidworks experiments and ended up with th...

New videos!

http://www.youtube.com/watch?v=NmjubycCV6E


http://www.youtube.com/watch?v=ONoiUrY8fWA

cheers

Here is another project that I finished... A small subminiature tube head: [img:1024:683]http://i1303.photobucket.com/albums/ag159/Thomas_Eduardt_Hafemann/DSC_0383_zpsn1zpl0zd.jpg[/img] [img:1024:683]http://i1303.photobucket.com/albums/ag159/Thomas_Eduardt_Hafemann/DSC_0378_zpsfyxqnkn8.jpg[/img] [im...

Hi, after some months, here it is: I made a solidworks version of it: [img:737:681]http://i1303.photobucket.com/albums/ag159/Thomas_Eduardt_Hafemann/renderCAB_zpspnzsjxq8.jpg[/img] the final version: [img:1024:683]http://i1303.photobucket.com/albums/ag159/Thomas_Eduardt_Hafemann/DSC_0951_zpszeoyodst...

Hi,
some voltages look strange to me, but I didn't build this amp yet.

The first grid shouldn't have dc on it , is it really 8,7V?

The second cathode and the power tubes cathode shouldn't be 0V, unless they're grounded.

And the heater voltages?

This thread keeps getting better...

You managed to squeeze one more tube in that tiny little amp!

If you can, please make a video. I would love to hear it. It looks awesome.

Cheers,
Thomas