Problem with 3Knob Tonebender

solderboy · Post by **solderboy** » 08 Nov 2007, 13:08

Hi All,

i build a Tonebender 3Knob Circuit (FuzzCentral)..
For lack of Ge Trannies i build it with Transistor Sockets
and used PNP Silicon for Q1 and Q2
At Q3 i used an AC188k

running it at full throttel it sounds pretty good.. fine Distortion..
but... i cant drive it at lower gain or turning the Guitar Volume down..

when the Tone dies away at one point the Distortion crackles away and the Tonebender mutes the sound (like a noisegate)...
Playing at lower Gain or with Guitar Volume down it sounds like a fart that is made into a trumpet (but a wet one.. LOL )

can anybody give some suggestions where i should search the error?
i checked it several times, but found no missing junktion or something like that...
is there a way to measure the voltages ?
As i measured the Collector Voltages Q1 = 2.25v / Q2 = 2.25v / Q3 =8.49v (if i done it right)

Thanx for Your Help !!!!

Greets
Solderboy

analogguru · Post by **analogguru** » 08 Nov 2007, 13:31

Add a 50k or 100k trimmer in series to the resistor from base to gnd of Q1. Adjust it to obtain approx. 5,5 - 6V at the collector of Q1/Q2

analogguru

solderboy · Post by **solderboy** » 08 Nov 2007, 14:07

Hi Analogguru,

Thanx for Your Help... i'll try that at home this evening...

Cheers
Solderboy

frank.clarke · Post by **frank.clarke** » 08 Nov 2007, 14:59

Q3 is way off, I get about 4.3V there.

solderboy · Post by **solderboy** » 08 Nov 2007, 15:33

Hi,

than all Trannies should have Collector Voltage around 4.5 Volts?

i'll check that too.../ play a bit around with some Pots adding to the Circuit temporarily..

THANX
Solderboy

solderboy · Post by **solderboy** » 09 Nov 2007, 11:50

HI,

DAMNED !!!!... i killed my TB Circuit yesterday... now it sounds nothing... DEAD... LOL...

i have to build a new one...

laughing on

Solderboy