I'm selling a Peavey Valveking 112 50w tube combo amp and need to let a prospective buyer know how I got my tone.

For the past few years I have been running it through

Guitar-->Amp-->MXR Eq and an effects processor through Fx loop

The amp is LOUD - cant take it over 2 without being moaned at.
What I did was to run the amp signal through the fx loop into an M-Audio black-box fx processor, with the guitar input turned down really low so there was no clipping.

I could then turn the volume up to about 7 on the amp and drive the tubes real hard (i think?) without being massively loud, as I could control a 'master' volume on the fx box. The amp definately sounded so much better and became way more touch responsive when I did this, and the tubes got far hotter.

What was this actually doing to the signal? I guess it came back to the amp digitised? Was increasing the volume on the amp actually driving the tubes?

TL;DR - Sent amp signal through fx box in the fx loop - set volume high on amp, controlled actual volume on fx box - what did this do?
Sorry to say, mate, but that technique doesn't give you that 'power amp tubes being pushed hard' tone because they are not being pushed hard. All that fx box does is limit the signal going to the power amp tubes. In order to get that 'pushed power amp tubes' tone, you need to actually push your power amp tubes by hitting them with a lot of signal. The way to do this and manage the volume is with a proper attenuator; a device that goes between the power amp tubes and the speaker.

And in answer to your question, you might have caused wear to your power amp tubes unnecessarily.
Last edited by NakedInTheRain at Jun 7, 2011,
On any all valve amp you have a preamp section and a power amp section, each with its own tubes/valves. The gain knob on your amp (if it has one) drives the preamp section, while the volume knob drive the power amp section.

Generally, you'll get the basis of your sound out of your preamp tubes (nice and clean/crunchy/High gain/whatever) and your poweramp tubes will round out the sound and add warmth/sweetness/shimmer, depending on what valves it has and how the amp is voiced. Thats why tubes amps sound better turned way up.

EDIT: ^ thats pretty much it. You had your power amp section driving, but with low signal going into it you're just going to stress you valves. They're meant to be used hard, but when you do they get worn out, and by using a weak signal you're wearing them out unnecessarily.
Last edited by guy_tebache at Jun 7, 2011,