Hello,
I have a strange problem: after i have built a couple of 3 knobs ToneBender using GGG layout (and all sounded very good after i modify a little the 10K resistor of Q3 and i used trannies having the gains like Q1=50-70, Q2=70-90, Q3=90-110), i tried to build a 3 knobs ToneBender using Tonepad layout i have a big trouble: the TB sounded like crap...gated...horrible!!
I tried to bias Q3 but i couldn't...i changed over 20 trannies and no effect...i can't obtain more than 3V on the Q3's collector (from a 9V supply).
Does anyone know if the layout have some mistakes?
Link? The layout should be simple enough. My guess is Q1 isn't biased right, 3V on Q3 shouldn't sound too bad.
what is the bias voltage on the junction of 10k and 18k resistors?
thx a lot...my voltages are (without biasing - 10K resistor on Q3's collector):
Power supply: 9.15V
Q1: E=1.43 B=1.44 C=3.50
Q2: E=1.32 B=1.42 C=3.52
Q3: E=0.00 B=0.05 C=2.60
The bias voltage at the junction of 10K and 18K resistors: 4.60
All voltages are negative, of course!
http://www.diystompboxes.com/smfforum/index.php?topic=64677.0
mac
Quote from: gigimarga on February 21, 2008, 01:23:36 AM
I have a strange problem:
...
Does anyone know if the layout have some mistakes?
Whenever something that you don't understand happens in an effect, Mother Nature is trying to tell you something.
It's nearly always something about your having made a mistake, or not understanding something about what you're doing.
It's rarely someone else's mistake, although that does happen sometimes, and it's almost never a bad-new component.
;)
:o
Q1 is super wrong, take a look there.
Which must to be the right voltages?
First item:
http://www.google.ca/search?q=%223+knob+tonebender%22+voltages
Thx!