The Tubescreamer Hiss Generator! (Need Help)

[Ortiz]

I've made a Tubescreamer from General Guitar Gadgets (my first pedal)  and to my dissappointment, it isn't working.

When I turn it on, all I get is hiss. The volume affects the volume of the hiss, the tone affects the tone of the hiss, and the gain affacts the intensity of the hiss! But no sound is actually coming from the guitar. I checked with an ohmmeter and the signal is getting to the board.

Parts are per the layout except a 47pF cap in place of the 51pF cap and a 2N4401 for Q1. (I was told the capacitor wouldn't matter.)

Voltages:
IC
1 - 4.05
2 - 4.15
3 - 4.06
4 - 0
5 - 8.12
6 - 4.06
7 - 4.05
8 - 4.06

Q1
E - 7.5
B - 8.1
C - 8.12

Q2
E - 2.573
B - 3.087
C - 8.1

Any help is appreciated - Thanks!

[R.G.]

Q1
E - 7.5
B - 8.1
C - 8.12

This is at least one of your problems. The base of Q1 seems to be shorted to the collector or to the power supply. This effectively prevents the transistor from passing any signal at all. You likely have a flaw on the PCB or a solder short, but there are other flaws. The base of Q1 should be about the same voltage level as the base of Q2.

[Ortiz]

Thanks for the reply.

The base and the collector are in fact shorted. But for the life of me I can't figure out where. 

I guess I'll keep looking.

[Ortiz]

It works!

Apparently there was a very tiny flaw in the PCB which was remedied with a hobby knife.

Thanks for the help! 

[R.G.]

Hey, congratulations! It's great when it starts up and flies, isn't it.

Good work with the hobby knife.