Making an audio probe

[killerkev]

Can I make a audio probe by plugging in a guitar cable to a mono jack and solder a wire to the sleeve for ground connection and solder the 0.1 uf capacitor to the tip? Looking to make one up quick. Thanks!

[bancika]

yeah, why not. you can solder two wires and on one going from tip solder cap. other cap lead can be your probe and solder alligator clip on ground (believe me you'll need it)
cheers

[R.G.]

Oddly enough, there's a picture of just that at GEO. I think it's linked through the FAQ here.

[brett]

Use a 630V cap and you'll be able to de-bug valve amps, and be safe around mains voltages.

[zjokka]

I instinctively made my probe, remembering the idea vaguely, by just wiring it all up hooking up guitar and miniamp and using an additional alligator clip to the output jack's positive tab.

I remembered the idea vaguely, like I said, and forgot about the cap. Is it necessary for safety reasons in such low voltage application, or what is the real purpose?

thanks
ZJ

[Arno van der Heijden]

DC blocking...

[brett]

Hi
Depending on the amp, you might be able to get away without the cap.
But to be sure, use one.  It's only 20c. 
While you're at it, build a ruby amp and get an old speaker and you won't have to use a good amp.  Best $5-10 you'll ever spend.
cheers

[zjokka]

Hi
Depending on the amp, you might be able to get away without the cap.
But to be sure, use one.  It's only 20c. 

So is my amp! Tis a real cheapo jap beast, have to post some pic someday, is a tiny solidstate practice amp, treble/bass is one knob, vol is one, and then three knobs for vibrato setting. Weird.

Anyway, the audioprobe is the only way to debug a system, and a great way to learn.

While you're at it, build a ruby amp and get an old speaker and you won't have to use a good amp.  Best $5-10 you'll ever spend.
cheers

OT:
Ever since my Ikea eureka moment, I'm whacking them out daily. Piggy NPN Fuzz face completed, Piggy NPN Rangemaster working great, boxing and lettering tonight. Want some new stuff, and was really thinking about that Ruby amp. Now it's Ruby for sure...

Brett, don't understand how you belittle your piggyresearch in some other thread like you did. Does anybody still make a si fuzz without pb-ing. I'm thinking about throwing all my si transistors in one big bin and only sort on gain and type, then when making a fuzz just take out two of almost the same gain and finetune with resistor.

As fun and attempt at demystification of the GE transistor myth, I would want to document a project where i build a great fuzz out of garbage. One radio would do, if it's got enough transistors. $0 Fuzz... 


thanks still
zj