bsiabII units vary pretty wildly... why? matching fets?

[nag hammadi]

i have built a bunch of the bsiabII's, and it is my favorite overdrive to date.

thing is, the tone varies quite a bit from unit to unit. 

one thing i noticed is that the "greenie" caps seems more shrill than the "browninsh red" caps.

i have pretty much stopped using the greenies.

now i think about the fets.  how important is it to match them REALLY?  i have read several different opinions here and at byoc.

thoughts?

[MartyMart]

You could build 5 of them, from the same "batch" of resistors/caps/Jfets and they will all
sound slightly different !!
Cap value tolerence is +/- 20%
Your resistors, unless 1% metal film, will be +/- 10%
Jfet matching isnt required for the BSIAB, but may help across multiple BSIAB's ...
.... so, using "quite similar" parts wont do it, then using different cap types ....... 

YUP, they are going to sound different UNLESS 100% of the parts/wire/pots/layout is EXACT

MM.

[nag hammadi]

i realize they won't be identical, but i was getting results that varied A LOT.

i do use 1% tol resistors, and usually 5% on the caps iirc.

the most difference i noticed was between those caps, believe it or not.  steve at small bear seems to think the grreenies are inferior as well, so i don't think i am a total lune there...

so no matching eh?  sweet!

[John Lyons]

There will always be small differences in caps and resistors but I would think that the FETs vary the most.
Is the tone varying a lot or the gain?
I wouldn't think that the caps would make a ton of difference (between polyester, mylar, polyprop or polysterene) maybe if you use all ceramic caps compared to all film caps...
If you want a higher consitancy with FETs you can build up a little FET tester and sort out your stock before building with them.

John