Tube Amp Archive

Yes, it affects the tone for all pickups. The neck pickup is less harsh at high volume just due to it's tonal nature. I have both bridge and neck pickups fairly low (on a les paul) as it is since I prefer the tone of it this way. I have played around with this some though. I may try a single-ended o...

I would have to say it's at least partially related to pick attack. At low volume the pick attack is quite percussive and pick harmonics are easier to come by. Some of this is lost at higher volume and the highs become a little harsh.

I can see on a scope that the PI and output tubes are not compressing. The master on 3 or 4 is pretty loud and unpleasant sounding. This could just be the reaction of my ear to higher volume. Perhaps in a larger room, it would be less noticeable. I was just wondering if anyone else had encountered t...

When I encounter the unpleasant sound at higher volume, I don't have the master volume set so loud that I am driving either the pi or output tubes into saturation.

I have attached the schematics if you want a deeper look.

Both amps have basically a Marshall JCM 800 type of circuit with some variations in the preamp. Both have effects loops and master volume. I have tried a number of things with the output stages (EL34s, 6l6GCs, 2 pentode 50W config, 4 pentode 100W config, cathode and fixed bias, inter-stage transform...

Thanks for the tip. I'll take a look at the waveform offset between the two volume levels and see if that's what's going on.

I have built/modded a couple high gain amps that both exhibit an issue where, when turned up via the master volume to the output section, the tone changes in an unpleasing way. At low volumes, these amps sound very much like I want them to (heavily over-driven). When I turn them up, the tone becomes...