Testing methods?

Started by greenacarina, November 16, 2006, 05:02:38 PM

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greenacarina

As I get into the testing phase of building a pedal I have to wonder what other guys do to create some kind of input sound when poking around with an audio probe? I'm working alone so I don't have someone there to strum a guitar while I poke and listen. I thought about using a delay pedal with a sound loop. What do you guys do?
Thanks.
Chris

puretube

when I don`t have a signal-generator (function-generator) at hand,
i wire the line-out of a radio, record- or cassette-player, CD-player,
or whatever can send continuous signals to the device to be tested.
(a second wire connects the grounds...).

MikeH

I lay my guitar flat and put my ebow on it.  Way up by the nut so that it just gently vibrates the string, instead of sending it into psycho-buzzing fury.
"Sounds like a Fab Metal to me." -DougH

R.G.

Have you read about the "Quick and Dirty Oscillator" at GEO?

One transistor and a few parts - instant oscillator.

http://www.geofex.com
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

Pushtone

Quote from: R.G. on November 16, 2006, 07:16:04 PM
Have you read about the "Quick and Dirty Oscillator" at GEO?

One transistor and a few parts - instant oscillator.

http://www.geofex.com

Although I didn't build R.G.'s oscillator,
I got a tone generator kit for $12.00 and put it on my testing/breadboard rig.
I use an old active computer speaker on the bench to listen to a circuit before I take it over to the amps.
It's time to buy a gun. That's what I've been thinking.
Maybe I can afford one, if I do a little less drinking. - Fred Eaglesmith

RaceDriver205

lol, those are the exact same jumper leads, breadboard and jumper kit that I have.

rogeryu_ph

Guys, I'm interested to build an audio probe as part of my tool, but how? Is there a ready pcb pattern and how to use the probe. Technically i'm not but I could try. I saw the quick and dirty osc by RG but don't understand the schematic works but I done several  project at tonepad as long there is a pcb pattern. Thanks guys in advance!!! 

greenacarina

Quote from: rogeryu_ph on November 16, 2006, 09:35:50 PM
Guys, I'm interested to build an audio probe as part of my tool, but how? Is there a ready pcb pattern and how to use the probe. Technically i'm not but I could try. I saw the quick and dirty osc by RG but don't understand the schematic works but I done several  project at tonepad as long there is a pcb pattern. Thanks guys in advance!!! 

I just put one together and it's a great, simple tool to have!
http://www.geofex.com/FX_images/audioprb.gif
The capacitor is .1 uf (kinda hard to see in the picture). Basically you turn on your project pedal, provide some sort of input (strum you guitar, etc..), and the audio probe is your output lead. The ground clip goes to the "sleeve" terminal of the jack, and you can probe around the circuit point-to-point starting from the input and see where you get sound and where you don't.
Good luck!
Chris

GibsonGM

I recorded like 5 minutes each of a sine wave at 220, 440 and 1000 hertz onto a CD.  Got the sine wave from Visual Analyser 8, free oscilloscope software, and cut/past in Cakewalk to make it longer.   I run the CD line out from the player, turn volume up to get a reasonable voltage on it (like 100mV), and insert that into my effect.  Then I kill the speakers so I don't go nuts  ;)  This is the same effect as a guitar note, really helps when using the audio probe...
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rogeryu_ph

Greenacarina, thanks. I just need to clarify this. The picture shows the output mono socket... and the one leg of the 0.1uf mylar cap is solder to the tip of the ouput socket ... and the other leg is use to as the test probe... the blue wire soldered to the sleeve of the socket and connected to where?  Also, when using I'll just power on the pedal and put signal on input socket with guitar then strum to make signal... and the output is connected to a small speaker? Correct me if wrong.... But I'll thank you again for the greaaat  adddiitionalll knowledgeeeee.

greenacarina

Quote from: rogeryu_ph on November 17, 2006, 12:36:26 AM
Greenacarina, thanks. I just need to clarify this. The picture shows the output mono socket... and the one leg of the 0.1uf mylar cap is solder to the tip of the ouput socket ... and the other leg is use to as the test probe... the blue wire soldered to the sleeve of the socket and connected to where?  Also, when using I'll just power on the pedal and put signal on input socket with guitar then strum to make signal... and the output is connected to a small speaker? Correct me if wrong.... But I'll thank you again for the greaaat  adddiitionalll knowledgeeeee.


OK, one leg of the cap is soldered to the tip of the socket and the other leg is your test probe. The wire soldered to the sleeve will have an alligator clip (it's not a roach clip, I swear!) attached so you can clip it to the ground portion of the circuit (I use the sleeve lug of either of the 1/4" jacks)
Hope this helps!
Chris


rogeryu_ph