freestompboxes.org

Krinkle wrote:

soulsonic wrote:Honestly, you could probably build this with nearly any chip and get pretty much the same sound.

+1

I agree it's nit-picking but I was just wondering if the designer had some preference...I'm guessing the op amp does not come in a single package or else it would have been used instead.

old thread revival...

the schematic for this is a bit different then other opamp buffers i've seen, such as the amz opamp buffer, or the one in the klon. is the bs2 an improvement, or just different? also the charge pump circuit is different than madbean's or others i've seen (including the spec sheet for the maxx1044), so same question: is there an advantage to the bs2 design? or is it just a different take?

thanks

I have one and opened it up when I got it to check out the circuit and here are my thoughts:

1. The 20 pF capacitor on the input is for R.F. rejection, not for stability. I use one on my discrete Szlaki pair JFET buffer for just the same purpose.

2. I question the use of the 5532/5534 in this circuit as the input impedance of this family of op-amps is too low; the input bias resistors would attenuate the signal too much. Something JFET-based would probably work better. People "in the know" still don't have any idea what op-amps Mario Marino put in these things. Incidentally, Dave Friedman of Rack Systems, Ltd. designed the BS-2 and is similar to the Tone Freak "Buff Puff."

3. Yes, that MAX1044 voltage doubler circuit is correct and I believe I saw the original circuit at GEOFEX or somewhere like that. I could have sworn it was in the application notes, too.

4. Always use a transformer to split signals.