voilà ce que je cerchais...
Citation:
Not sure if anyone likes to get geeky about things, but if so here's some information about your BBs so you know what's running under the hood.
The BB preamp is a modified TS-808. No joke, and also realize this doesn't make it any less of a pedal. A JTM45 is a modified Bassman, but they're both great amps. Anyway, the BB's extra gain (comparatively) is from the 1MA gain pot in the first opamp stage's feedback loop. The TS-808 uses a 500kA stock.
The second opamp stage is just like the TS-808's tone control, but instead of a 20k or 25k poteniometer, it uses a 19k fixed resistor to set the RC filter at a preset value.
From that point, the BB (and AC, and RC) adds a second IC chip (a second JRC4558 or correlative variant) to push the signal through the secret to the Xotic's tone - a Baxandall tone stack (ie - the Bass and Treble control). If you've played a THD Univalve or Bivalve, you've played with a Baxandall. Its a very sweet and natural sounding tone stack. Play with it on Duncan's TSC and see how much it differs than other stacks.
Its voltage divider is also constructed slightly differently than the TS-808.
By the way, the AC and RC are essentially the same story. The AC uses a 500kA gain pot just like a Tube Screamer, and the same parallel clipping diodes (1N4148 or 1N914) as a TS-808. The RC is exactly the same as the AC, but it uses a total of 6 diodes in the "clipping" section (ie - first stage's feedback loop). 3 in series parallel to another 3 in series. This increases the collective voltage threshold of the diodes. As a result, you get MUCH less clipping and MUCH less compression. I think the BB might have a different RC filter right after the output buffer to slightly bring the midrange down.
il sait decidemment bien des choses cet homme...
