I'll gladly make a fool of myself saying that for me all tubescreamers and or other basic distortions sound sound lame in comparision to an Umble. Blistering highs, perfect control over the mids, bassy and sweet if you like that. Incredible. I couldn't care less about the question "does it sound like a Dumble amp?" -- this is knock out distortion for me. I've stopped lending it to guitarist friends (wanting just their judgement), they all come back begging me to build them one.
Well, they should buy a Boss Blues Driver -- it's in the same league though noticeably duller and less fliexible tone wise, cf single tone control.
Steve's music center doesn't hesitate to pull Keeley's pants...so it seems. But what I am more suprised about is that there are about 100 caps on board.
Boss BD-2 Blues Driver Mods
This is not all-inclusive in what can be done to the Blues Driver. It is meant to give an idea of where the tone can be improved or changed. All of the changes are subtle but when packaged together offer a nice improvement.
D3 Change this 1SS133 to a different (1N4002) diode for asymmetrical clipping. This adds second order harmonics. This adds to the tube type sound.
D7 D8 D9 and D10 Change 2 of of these diodes from 1SS133 to a single 1N4002. More second order harmonic distortion. Although the change is slight, it can be perceived. Keeley actually takes out one of the two pairs and replaces it with a single 1N4001.
C1, C7, C6, C12, C13, and C15 Change this electrolytic capacitor to a 10uF tantalum. Tantalum capacitors sound better than electrolytic capacitors. Keeley likes these anywhere there is signal coupling at this high a value. Tantalum capacitors are easy to find in this range.
C14 Increase input coupling capacitor value to 0.1uF for increased bass response from your guitar.
C100 Here is where Keeley can affect the tone control. He prefers a little more lower-midrange and bass frequencies through the tone section. You can increase the lower frequencies by increasing the capacitor value to 0.033uF. Install a switch to add a 0.068uF cap in parallel with this value for the Phat Mode!
Most of the ceramic caps are changed to Expensive Silver Mica (Available through Small Bear Electronics http://www.smallbearelec.com or http://www.mouser.com or http://www.digiley.com). This is what makes the Keeley mod sound so good. A noticeable reduction in noise. An increase in the smoothness and no harshness left. This type of upgrade is not found in anyone's mods. The best sound is right here.