I built a rangemaster tone 2day using an AC187 Ge NPN tranny. It sounded great on both SS and a tube amp, added shining overtones and over-all buff and attitude... BUT soemthing was wierd... all of the tranny's voltages were measured at about 7.20V (8V batt.) and the trimmeres I used (50k in series with a 47k to ground Rbais & a 5k emitter res.) didn't seem to change a thing. AND at first I plugged the biasing res. wrong (i.e 470 to GND and the 47k+50k trim to v+) - although it wored just fine.... how was that possible?!?!?!?!?!?!?!?!?!?!?!?
BTW - I used a Ge diode from E to B as suggested at fuzz central and plate to plate, and I used a .0068 cap for inrut instead fo the original .005
I also wanted to say thanx to all the people here, helping to get these little basterds running, enriching (is that a word?) our tones :)
:)
Can't anyone expalin me this?
You can get them Ckt's to 'run' sometimes even with 'mistakes'.
If you measure the Q voltages with the 'miswire' compared to 'right', you'llprobably find a transistor that is not optimally biased, but enough to still amplify.