I am looking for audio probe info I went to the GEO site but the picture was unreadable.Anyone got a clear well explained drawing for a simpleton like me?
Here is a link on Paul Marossy's page - a very clearly drawn, and well explained drawing of the DIY audio probe (I'm assuming that'swhat you're looking for):
http://www.diyguitarist.com/PDF_Files/DIY-AudioTester.pdf
Once you get it set up you will be thrilled at the amount of time it will save you while troubleshooting.
Here's what I did.
Take a standard guitar lead (maybe buy a very cheap one?)
Cut one end off. Plug the other end into your amp.
At the cut end, attach a wire and small alligator clip to the outer, shielding wire (this is your earth connection)
Attach one leg of a 0.1uF cap to the centre wire.
The other leg of the 0.1uF cap is now your audio probe.
good luck
I used an old tester lead, attached to the 0.1 cap, the cap to the tip sleeve of a 1/4" female jack, the ring of the jack to a long cable with an alligator clip. This way i can use a standard guitar cord plugged to an amp.
I find much easier to poke the circuit with a tester lead than with a bare cap lead (bends, cracks...).
Hope it helps
Quote from: Greg MossHere is a link on Paul Marossy's page - a very clearly drawn, and well explained drawing of the DIY audio probe (I'm assuming that'swhat you're looking for):
http://www.diyguitarist.com/PDF_Files/DIY-AudioTester.pdf
Once you get it set up you will be thrilled at the amount of time it will save you while troubleshooting.
One point, don't use a 50V cap. Might as well use a 630V cap - it's cheap and the leads are stronger.
Thanks for the replies I had this info but as usual put off doing anything with it.I realise now it is a must have tool.
Another thing to consider with an audio probe, if you connect two back-to-back 5.1V zeners from ground to the amplifier side of the 630V cap, you'll protect your speaker (& ears) a little more. The zeners should point in the opposite direction from each other, but they're in series. That stops the signal being injected into your amp from ever going over 12 volts peak to peak. It's more useful for tube amps than pedals, but why not have a universal tool?
YOu could limit things even more with a pair of parallel green LEDs just like a regular diode to ground clipper. That puts things at about 5 volts peak to peak.
Nice drawing Paul!
Take care,
-Peter
:oops: I once used a cheap piezo earphone as audio probe substitute, not really good one but I had nothin else available, :oops:
Quote from: aronOne point, don't use a 50V cap. Might as well use a 630V cap - it's cheap and the leads are stronger.
What's wrong with a 50V cap? Would it cause the audio probe not to function well?
Quote from: zenerQuote from: aronOne point, don't use a 50V cap. Might as well use a 630V cap - it's cheap and the leads are stronger.
What's wrong with a 50V cap? Would it cause the audio probe not to function well?
Nothing's wrong with a 50V cap, but with a 630V cap just a few cents more and being a lot more rugged, I'd go with that.