bias trimmer question

[squidsquad]

On my differential distortion....I have a 100k trimmer on Q 1's collector...as suggested.  Problem= VERY tiny *sweet spot*.  Should I try a 48k resistor w/a 50k trimmer to get a *wider window*?

[toneman]

ohm out the 100K 2 C what it's dialed 2...
say it's bout 30K---so it's on the low-side-of-middle.
put a 50K trimmer in with 2 24Ks on either side.
MayB move the trimmer from the middle to one of the ends.
usually halfing a value, or doubling it, is a good way to experiment.
experiment...play....tweek....listen....test....eat...sleep...occasionally...
T

[squidsquad]

Might add.  I shorted out the 6k2 on Q 1's emitter....so....maybe that's why the bias is touchy?

One more question:  would that resistor be the one to replace w/a pot for gain control?  For I believe when I accidentally shorted it...the thing got super loud....so I soldered it...HA!

Dunno how to post pics....but this shows you the schem w/my *short* drawn in:   http://www.freewebs.com/squidsquad/mistake.jpg

Still tryin to grasp basics!  (and write without screwing up)
In the first post...the trimmer goes to Q 1's BASE...not C....duh.

[squidsquad]

Thanks...hadn't thought of that way.  This thing is SO close to bein great.  An input cap switch....and some gain control...and I'll be in fuzz heaven.  PS...I added a Fetzer valve circuit after to boost output.  It goes (w/cap switch) from a nice treble booster to super fat-compressed sustain for days.  Now, if I can just get it to clean up a bit more via ax volume...WOOF!

[petemoore]

Say I find that around 33k is the sweet spot, and I want a surface mount adjust instead of a board trimmer.
 I'll start with a 10k or 20k pot [depending on how much past the sweet spot I want to get and how much usable potrange I want to waste] in series with a stop resistor of say 27k. Starting with a '20k pot/22k stop resistor', that gives me between 22k and 42k adjustment, adding a 22k resistor across the pots outer lugs makes for R range between 22k and 32k///
 Use of a second pot to find the resistances you want them set at, then picking the fixed stop and taper resistors, you can get just past the range you might want, with fine tuning over a large amount of the potrange, or finer tuning with less range.