Grateful Dead Music Forum

An online search for the Alembic Blaster schematic reveals several schematics that all fall into one of two categories. One employs two capacitors while the other uses three caps. Anyone know the difference? Is one preferable? Knowledge and opinions appreciated.

Thanks,

Bill, tgo

As long as you're asking, also, sometimes the ones showing 3 caps describe the circuit as "improved." I'd assume this means the original version Jerry used had only 2 but is this correct? Also, I've read that replacing R2 with 27K or even 47k resistor still keeps the sound clean but offers more volume for lead boosts.

Mystery solved, I think - C3 adds power filtering, according to this pdf:

http://www.generalguitargadgets.com/pdf ... b_sc_i.pdf

Batteries don't need filtering. That capacitor will prevent voltage sag during loud transients.

sll wrote: ↑Sun May 23, 2021 8:11 am Batteries don't need filtering. That capacitor will prevent voltage sag during loud transients.

The circuit pulls very little current off the battery. The third cap was added for power filtering because that schematic and the associated kit were designed for install in a stomp box with a 9v plug option. It’s actually oversized to the point that you can pull the battery and still play off the stored energy in C3 for 10+ seconds.

R6 was added to reduce switch noises for a stomp box or guitar install with a bypass switch. Jerry’s was installed in an always on arrangement, without R6 or any switching.

The other “improvement” is lowering the value of R1 which is there to block radio frequencies.

For JG the preferable version only uses one cap. Going by this schematic you jumper R1 and omit VR1 and C1 wholly.

That is not to say it is preferable for the modern world of guitar since it is the prototype (=unfinished) that was in Alligator (and early wolf?). Can't be all that bad tho since waldo can sell it to happy customers.

But yeah if you want a like production Stratoblaster just use this schematic. The "improvements" are so that it can work in a stompbox with a DC plug but this has been said before.

Make all three and find out for real what's good