Help, my Dr. Boogey is lame!

[fpaul]

I am ready to start tinkering with this to try and increase the gain.  I read the following by dswartz on the dual rectal thread.

"In my case, i had troubles with lack of gain (believe it or not..it had a lot, but this thing is suppossed to be a gain monster) so i changed the first stage bypass resistor to 2.2K, and lowered some 470k resistors in some voltage dividers of the signal.
- test A LOT of j201 till you´re happy"

I am wondering which specific 470Ks I should lower and what value should I lower them to?  Also, is there some way test j201s to find "good" ones?  I know there is a JFET matcher but what values should I look for?  If I just try randomly plugging them in is there a systematic way to do it? Like plug into Q1 until more gain, then move to Q2 etc?

The distortion I'm getting is a good metal distortion but not much gain or sustain.  When I put an overdrive in front I start to get the sounds I was expecting.

Guess I could just use the overdrive but would rather have a stand alone pedal if possible.

[dschwartz]

Hi fpaul:
the lack of gain was specifically on that build, and never had a problem since then..

did you tweak the trimpots by ear or just let them sit at 4.5V? do that by ear searching for max gain..
Some j201´s give more gain than others..the test i do is just use a socket for fets and sit for 2 hours with a bunch of them and start trying out different j201´s, until i´m happy with it..

if you can identify a simple voltage divider, you will know where to change the resistors to get more gain (it will change freq response also), that post is too old and i don´t remember where i did those changes..

[RDV]

IIRC I had to use a smaller gain pot because there was so much gain I couldn't control the squealing.

You may have another problem causing the lowish gain.

How much noise at full gain? There should be quite a bit if it's running at full gain.

RDV

[fpaul]

Thanks for the replies.  I just re biased by ear and it is much better now.  I had a lot of fun playing with some palm muting stuff and the open chord distortion is very nice.  I'm not sure why it's better now because I fiddled with it quite a bit when I built it about a month ago, (first by ear then by voltage, then by ear again, new set of jfets, etc.) and was never close to satisfied. Now I think I'm close, probably just need to try a few more jfets.

I guess I was expecting more of a monster with this pedal.  I sweated building it without shielded cables but finally went ahead and did it.  The thing is pretty quite and I don't even have it in a box yet.