GGG ITS8 Transistors question

Started by heavy1011, May 23, 2015, 03:49:54 PM

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heavy1011

Curious about other who have built the ITS8 LDO version from GGG,
Using MPSA18 Transistors in the GGG ITS8 I'm getting Base readings
lower than the Emitter.

Q1    C : 8.8
         B : 2.7
         E:  3.1

Q2 : Same

It's about 90% there with some splatter and warble when distorted,
everything checks out voltage wise.

Debugged and discovered volume pot was faulty so now I'm 95%
there but still have Q1 & Q2 and not quite sounding right.
All functions work with the mods I'm at a loss.

Know first thing is to get another type of transistor which I have on
order, this is my second build and both have Q reading with base
lower than emitter.

Was hoping to get the second one right and use it to debug the first
one and now they both sound the same.

Wonder if anyone has had issues using MPSA18 transistors in this
build?

Have read quite a few posts with guys coming up with defective
parts resulting in the base voltages being lower than emitter.

Frustrating is an understatement at this point, have built a few
pedals and only seem to have trouble with GGG's builds for
some reason.

http://www.generalguitargadgets.com/pdf/ggg_its8_sc.pdf

http://www.generalguitargadgets.com/pdf/ggg_its8_mods.pdf

Thanks for any help and insight, it is greatly appreciated!


heavy1011

#1
*Found dead cap C8 1 uf*

Misread with multi meter C8 good