[quote author="jarlehal"]
insideout: you mean trimmers on R4 and R9 right? And you got them down to 12v? What's the voltage over R5 and R10 then (FETs out) ? Please report back when you have done your "signal-thru".[/quote]
ok, have done some more on this. So i had set the 4v across r5/10 with the 100k bias trimmers, then got 12v at c2/c4 by using 5k trimmers in place of r3/8.
revisiting the voltages with all components in, across r5/10 they are both down about 0.4v. ie they now read about 3.6v.
volts at c2=12v (ie hasn't changed), but volts at c4=13.4 (ie up 1.4v).
THe audio through the mic input is not flash.
With fetboy gain on full, acoustic guitar strummed with pick, studio projects b3 about 10 inches away, going into a motu828 balanced line in, I get about -30 to -25db in my DAW and it sounds like a fuzz box! (I knew it was supposed to be a funky design, but....).
By comparison, if I plug that same mic into the motu mic pre and trim it down as far as I can, I get a similar level but much nicer sound. So I'm guessing that the gain stages in the fetboy are somewhat off, as indicated by the voltages I have? (tho other threads seem to indicate they are near enough)
audio through the DI sounds really good, though a little low in level? A P-bass with EMG's, with fetboy gain on full, going into the same moto balanced line in, comes up in the DAW at about -15db. But it sounds good, unlike the mic input! Which I find a bit odd, seeing as there's only the transformer and a couple of bits difference in signal paths? (I used 100k for RL).
would the next step be to tweak the trims to get the volatges back to 4 & 12, or is that just barking up the wrong tree and I need to find those fets that give 12v? Or, seeing as the DI sounds ok if a little low, do I need to examine the components in the mic input path?
- Mike
