$6 Preamp Kit as Overdrive?

[GreenEye]

I noticed that Circuit Specialists carries a "general preamplifier" kit with 40dB of boost (Cat No. KIT 98 ).  It's $5.95.  Does anyone think it would make a good "booster" in front of a tube amp?  

I don't have a schematic, and there's not even a picture of what it is.  Perhaps it could be modded to turn it into a good overdrive?  I'll likely give it a shot down the road to see what it does.

[Mark Hammer]

40db boost is probably a little heavy-handed for a booster front end.  I stick a gain-of 4 preamp after a fairly normal output humbucker and it drives the bejeezus out of my amps.  40db is a lot more than that, and is really intended for bringing things like a voice microphone up to line level.

[petemoore]

Yes true, and yes, my buddy bought one and did this, sounded interesting going through the Boogie MkIV..just for cheep thrills.

[Paul Marossy]

I tried goofing around with a preamp circuit like that, but anytime I adjusted a pot on my guitar, it made loud, bad scratching noises which aren't audible normally. They really are meant for a microphone or something like a Martin Thin-Line style pickup.

[casey]

you could use it to push a passive eq circuit!

[Hal]

put in a volume pot :-D

[Paul Marossy]

The volume pot may not work without it making loud scratching noises...

[aron]

Not knowing anything about it, I'd still bet you could turn it into an overdrive. As for pot scratchy noises, simply put a blocking capacitor before the pot and it will stop the scratchiness from occuring.

[Paul Marossy]

A blocking cap, huh? Now, why didn't I think of that?!  :oops:
Hmm... maybe I can use mine for something after all.
What size should I try first, a 0.01uF?

[petemoore]

.01uf would probably roll off some bass...
 something like that or a .1uf .22uf etc.

[Paul Marossy]

Doh!   :oops:
I think I meant to say 0.1uF...

[GreenEye]

Found the pic of the board online at their site (click on the image to enlarge):

http://www.circuitspecialists.com/prod.itml/icOid/6039

PDF file has the schematic!

[Paul Marossy]

That is the exact same thing that I have, except that it was manufactured for an outfit called "KitsRUs.com". Maybe it's the same place with a new name... Anyhow, that PCB is exactly like the one I have. Check out this page: http://kitsrus.com/kits.html#k98

[aron]

I would start with a 1uF and work down from there - but it all depends on where the pot is in the circuit.

[casey]

That is the exact same thing that I have, except that it was manufactured for an outfit called "KitsRUs.com". Maybe it's the same place with a new name... Anyhow, that PCB is exactly like the one I have. Check out this page: http://kitsrus.com/kits.html#k98

if you look at their pdf of the circuit.....on the right hand side
it mentions kitsrus.com.

[Paul Marossy]

Aron-

A 1uF cap? I assume that would be an electrolytic?

Casey-

That's interesting...