skyripper getting no sound

Started by mantella, January 09, 2010, 01:55:15 PM

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mantella

Hi all, I just finished wiring up a skyripper. I plugged it in and got no sound. Double-checked wiring, solder connections, etc. Then plugged in an audio probe and a keyboard playing a loop, and there was sound going all the way through from input to output. It didn't sound "fuzzed" at all, but it was clear and loud. So, I plugged the guitar back in, and no sound again. I get a "whoomf" sound as I turn the volume pot on the guitar all the way up. But no guitar signal seems to be getting through.
There's got to be some ridiculously simple thing I'm missing here...

John Lyons

There are a lot of connections and switches. Take a deep breath, a cold drink, a clean schematic and layout with a colored
amrker and run down the lust of connections. Something is either not connected in the right place or turned the wrong way.
Remember that the circuit is Positive ground so the black battery wire goes to power not ground. PNP transistors and
make sure you follow the schematic notes on biasing with the rip switch etc.

John
Basic Audio Pedals
www.basicaudio.net/

mantella

okay, I think the cold drink idea helped  :icon_cool:
Thanks man, I forgot it was positive ground. Also, I had a weird connection on the input jack that was messing things up. Now I get sound all the way through (with guitar). Just need to bias and see if I can get it to all come together.

Ry

Have you tuned in the transistor voltages with the trimmer pots?  Did you use a layout for it?  I rebuilt mine last month using a vero layout in the gallery.

mantella

argh, okay I thought I was making progress with this thing. I haven't been able to work on it all week, but am back at it now.
I can't seem to get any real voltage across the Q2 or Q4. Measuring collector to ground I get:
Q2: -75mV
Q4: -0.3mV (switch 4 open or closed)
The trimmers don't seem to affect anything, and I don't get any real fuzz tone yet.
I got these AC128's from ebay, and I'm wondering if they might be suspect.

John Lyons

If you have other 128s to try I would put in a socket for those and try a few.
You should be able to get some voltage though. At least a few volts.
Are you sure you have them in the right way around?
Basic Audio Pedals
www.basicaudio.net/