Tube Amp Archive

Hi there,
I‘m looking for a Lil‘ Devil amp from Hall Amplification or parts from Dana‘s kit, especially the PCBs to build one by myself.
If there’s anyone willing to sell or can point me in the right direction, please send me a PM.
Thanks,
Frank

Hi Phil,
Did you manage to finish your project?
I’m asking because I would be highly interested in building this Lil Devil. I already built a Trainwreck Express clone, but this amp is just too loud for frequent playing…
Thanks,
Frank

Good question. FWIW I used only SBE6PS and 416P in my build.

Colossal, thanks for you time to have a close look at the photos. Good catch with the cathode lead to V1b p3, it is punctured indeed, I will replace it. I will check and re-do the anode connection on V1_pin 6. 10k input resistor: done. C2 is hidden from C3 (huge orange drop). I was told that micas m...

Any ideas at all where the bass heavy behavior of my amp could come from? The low end is booming and really annoying then something seems wrong. recheck the wiring of the tonestack I re-checked all pots and connections: Tone stack pot values: - Vol (1MA): Alpha A1M (measured value 1,03M) but now sh...

Excessive bass can itself be a symptom of oscillation, in rare instances. Do you have an oscilloscope? Use it to watch for oscillation. I have to say, I don't like those orange drop caps in there very much. I favor MKT1813 series Vishays. They're about as close as you can get to a modern Philips Mu...

then something seems wrong. recheck the wiring of the tonestack

Will do,thank. I'll keep you posted after the check.

yeah, tried this already Thanks eddiep1966 for the hint, though.

Any ideas at all where the bass heavy behavior of my amp could come from? The low end is booming and really annoying...

I already disconnected the NFB wire (R22/100k detached) as one of the first measures. Sound and playing feel changed, but squeal was still there.
Let me re-check...

in the meantime I went closer to the original circuit (C9 back to 0.1uF, took out the cut control) and tried out some measures: twisted the wires from the phase inverter to the el34 grids bigger grid resistors 39k at the power tube sockets grid resistors 68k at v2 and v3 (pins 2 and 7) adjusting the...

Roe wrote: ↑Wed Jun 18, 2025 7:29 pm try to twist the wires from the phase invert to the el34 grids. bigger grid resistors downstream also help with oscillation and blocking distortion. try 47k at the el34s and 68k at v2 and v3

Thanks, I'll try over the weekend and report back.

Tone stack wiring is very sensitive, so try moving leads around with a chopstick and looking for any that affect the tone of the squeal. Does the bright switch affect it? I agree on the heater elevation, none needed unless there is a cathode follower that runs Vh-k near spec limit. I tried as much ...

It's a sensitive design. Use high gain preamp tubes and turn it up and it's going to squeal at some point. Hand pick preamp tubes that balance the available gain. And don't expect that this amp can ever be dimed on all controls and remain stable. This is a high performance thoroughbred racehorse of...

Just recently I finished a build of TW Express clone, which was a fun project and still challenges me with an oscillation issue :cry: I did quite some research on the Express in the trainwreck sections of this awesome forum before and after the build but now I'm kinda stuck and I would need some hel...