Big Muff Ram's Head debugging - no sound.

[jimladladlooklike]

Hey all. Just finished putting together a Ram's Head clone using TagBoardEffects layout and I have no sound... Just a slight hiss when the pedal is engaged.

Here is the schematic:



And here is the layout with tone cap switch added:




I've recorded the voltages and they are as follows:

Q1:
E - 0V
B - 0.4
C - 7.6

Q2:
E - 0
B - 0.4
C - 7.6

Q3:
E - 0
B - 0.4
C - 7.2

Q4:
E - 0.1
B - 0.6
C - 7.7

D1:
A - 7.2
K - 7.6

D2:
A - 7.6
K - 7.2

D3:
A - 7.2
K - 6.8

D4:
A - 6.8
K - 7.2

DX:
A - 8.3
K - 8.1

Do these readings sound right or no? Any pointers would be appreciated.

Thanks in advance!

[jimladladlooklike]

To add to this, having used an audio probe, I have no signal at the base of Q1...

There is signal before and after R2 (33K) although it's quieter after - there's also signal before C1 (100nf) but not after. Is this the problem?

Thanks guys.

[thermionix]

When you say Q1, you mean Q4 in the schematic?  Are you sure your R14 is 100K and not 100R (or less)?  With vero, it could be almost anything, missing cut, solder blob, you name it.  Can you post pics of your board, front and back?

[jimladladlooklike]

When you say Q1, you mean Q4 in the schematic?  Are you sure your R14 is 100K and not 100R (or less)?  With vero, it could be almost anything, missing cut, solder blob, you name it.  Can you post pics of your board, front and back?

The resistor is the right value. Yes, sorry, it's Q4 in the schematic. Here are a few pics. Excuse the mess!

[jimladladlooklike]

Never mind.... I had the transistors in the wrong way. Read the pinout wrong... Thanks for suffering my stupidity anyways!

[thermionix]

Glad you figured it out!  Nice clean cuts, and shiny solder too.  Carry on.

[jimladladlooklike]

Thanks!