Hello Hello--
O.K., I've settled on two 2N3906's in piggyback mode with a 10K pot wired between the emitters. Nice variations of "gain" ! There is a dramatic difference in the sound from one end of the pot to the other.......pretty good when changing from a Strat to something with humbuckers.
Brian.
If you like, you or I could write up a little diagram about using the 8PIN IC for piggybacking, and put that near Miss Piggy...It's the best way I know of to do the Pigging out of Q's [well the 10k V/R ain't badd].
Anyway some people have tried it, and seem to like it, it's a PDG method, might be helpful to Miss Piggy builders, just like Miss Piggy is helpful to FF builders.
Quote from: brian wenzO.K., I've settled on two 2N3906's in piggyback mode with a 10K pot wired between the emitters. Nice variations of "gain" !
If you mean, a 10K pot between the 2 emitters & the wiper goes to where the emitter of the "combined" transistor would be, then what happens when the wiper is in the middle, is that there is a lot of negative feedback to each transistor.
Hello Hello Paul--
The 10K pot is wired as a variable res. [Middle lug goes to one of the outside lugs.] I wired it in to see what value res. I wanted in the circuit and decided to leave it in there!
Brian.
Hello Hello--
After messing with the pedal, it seems to sound better [to me] with NO res. between the emitters. When the pot was set to 10K things got "flubby" and the noise factor increased dramatically.
Wotta you think, Brett?? Paul??
Brian.
Hi.
Yeah, I've noticed that "flubby" thing up at the 10k mark. I *think* I've tracked it down to low input impedance (about 8k - my humbuckers sound very muddy and my single coil not much better). Increasing the resistor to 22k (and the inpedance to about 16k) cleaned up the flub, but the tone was much less "low hFE germanium".
It's very cool that a pot works in the BossTone. In trying different piggyback resistors in the Miss Piggy, I find that more than a couple of kohms change requires re-setting the bias on Q2. It doesn't just sound bad, it doesn't give any sound at all! Tho a limited range would work ok (maybe 2.5k or 5k?).
Just 10 minutes ago I soldered a 10k resistor input resistor into a "flubby" Miss Piggy. But the Mrs is asleep, so I'll have to wait a while to try it out. (I got the idea from the "boutique" fuzzface, which uses a 50k pot wired as a variable input resistor. They call it the "bias" pot, but it is obviously there to vary the input impedance from low to high. I've not built one of these, but I'm fairly sure that it is there to control the "flub" and maybe other tonal components.)
cheers
Hello Brett--
Have you found that increasing the emit. re. value also increased noise??
Thanks-
Brian.
Hello Brett Again--
Actually, have you found that a circuit using piggybacked trannys is a bit noisier than it's single-tranny counterpart??
Brian.
Hi. Piggybacked trannies seem quiet compared to Ge, but noisey for Si (which seems odd considering they make for low gain). RG or someone with detailed knowledge would have a better idea than me.