Anyone seen the Seymour Duncan SFX-01 schematic?

[O]

I'm attempting to fix one up for a friend of mine, but I'm having a really hard time...
*shakes fist in the air*
(CURSE YOU SMD PARTS!!!)

Anyway, does anyone have a copy of the schem? The pedal basically does not pass the boosted signal, just the bypassed signal. The LED stays on whether the effect is engaged or not. From what I can see, there might be a couple of transistors flip-flopping the led on and off and they might be bad. The pedal doesn't have a diode protecting it from reverse polarity, so I'm thinking it either got too much juice, or the wrong polarity. Either way, I can't really do much without having the schematic...

If anyone can help, I sure would appreciate it!

[O]

Ok, searching through another forum, I found this pic. Since I can't read German, does someone know if it's correct? Kusi?

[kusi]

hi O,

the sfx-01 is a normal, discrete op-amp-booster, not very special (transistor-tripple). the only special thing is the resonance-switch at the input, you can use this before any booster ;-)
this is the same as in your sheet form JHS.


best greetings form switzerland,
kusi

[JHS]

To copy the SFX-01 (even w the schem) is mission impossible 'cos the trannies are unknown. You can use common trannies but they must be correct biased to get proper "class-A" action, so you have to re-calculate all R-values for the 3 trannies.

I don't think it's worth to spend any time on the original circuit, most SFX are noisy and pick up radio stations (maybe that's while he named it Pick-Up Booster).

Nearly any linear IC-type booster or other class-A booster like Jack's Mini-Booster can be used as the basic circuit. Alter the I/O caps and add a switch for the resonance mod and soundwise your booster will act like a SFX, w/o the noise and radio gaga.

JHS

[O]

Thanks for the replies, y'all... Maybe a call to Seymour Duncan is in order.