fulldrive not working

Started by blackbirdneo, May 31, 2006, 12:02:54 AM

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blackbirdneo

i built a fooltone fooldrive.
i used the layout from this site: http://members.surfeu.fi/jouni.tukiainen/schem_frame.html
i couldnt find any dp3t so i used a 3p4t rotary switch. a also added a dpdt switch so that i can fat boost the fulldrive
U1:(jrc4558d)
p1=4v
p2=4v
p3=4v
p4=0v
p5=9.2v
p6=4v
p7=4v
p8=4v

Q1:(2sc828)
E=9.2v
C=1V
B=1V

Q2:(2sc828)
E=9.2v
C=1V
B=1V

D1(the one connected to the ground:
A=9.2v
K=0V

D2(1n4005)clipping diode:
A=4.1v
K=4.1V

D3(1n4148)
A=4.1v
K=4.1v


i used my power supply: 9.2V

R.G.

QuoteQ1:(2sc828)
E=9.2v
C=1V
B=1V

Q2:(2sc828)
E=9.2v
C=1V
B=1V
This is at least one problem. The transistors are either wired incorrectly, or you are using the wrong pinout, or there's a hook up error. The schematic shows that C should be connected to 9.2V, not E.

Also, with B and C at the same voltage, the transistor cannot amplify. Even if the C and E voltages were reversed, the base must be 0.5 to 0.7V positive with respect to the emitter for it to act as a linear amplifier.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

blackbirdneo

my bad. i really need to wear my glasses when checking pinouts
q1&q2:
c=9.2
e=1v
b=1v

R.G.

Quotec=9.2
e=1v
b=1v
OK. That means that either the B and E are shorted together, or that there is no bias being applied, or something like that. A bipolar transistor cannot pass signal with its base and emitter at the same voltage.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.