Tonepad Rat no sound

[justinsane]

1.What does it do, not do, and sound like= No audio
2.Name of the circuit = La Rata
3.Source of the circuit (URL of schematic or project) = tonepad
4.Any modifications to the circuit? = 2N5457 instead of 2N5458
5.Any parts substitutions= LM386N instead of LM308

[justinsane]

1.What does it do, not do, and sound like= No audio
2.Name of the circuit = La Rata
3.Source of the circuit (URL of schematic or project) = tonepad
4.Any modifications to the circuit? = 2N5457 instead of 2N5458
5.Any parts substitutions=
2N5457 instead of 2N5458
LM386N instead of LM308
Q1 =2N5457
D =9.20
G =1.39
S =0



IC1 LM386N
P1 2.10
P2 3.95
P3 0.43
P4 0.00
P5 7.73
P6 8.32
P7 9.21
P8 3.03

D1
A (anode, the non-band end) = 0.00
K (cathode, the banded end) = 0.14

D2
A = 0.14
K = 0.00

D3
A = 9.21
K = 0.00

[Seljer]

I'm noit going too far into the voltage measurments and such, but an LM386 is not a suitable replacement for the LM308! The pinouts aren't even compatible.

The Rat's sound is partly due the the 308 chip, but try any other single opamp if you can't get it (TL071, uA741/LM741)

[justinsane]

My apologies the gate on the transistor is 0.00 and the source at 1.39.

[Seljer]

My apologies the gate on the transistor is 0.00 and the source at 1.39.

The voltages on the FET sound about right, you're going to have to change the IC

[justinsane]

will a TL072 work?

[Pyr0]

will a TL072 work?

No, you need a pin compatible single op-amp, so use something like the TL071, LM741, NE5534

[GGBB]

An OP07 will also work - that is what's been used in RATs for the last 10 years or so.  The TL070 is reportedly a great substitute if you can find one - but you may need to change the 30pF cap to 100pF or so to get the slew rate down to LM308 levels.  It's probably easier to find an LM308 than a TL070 though.  As for the TL071, LM741, NE5534 - they will functionally work, but probably won't sound RAT-like although you might or might not like it.