so If I wanted to build an audio probe to work in conjunction with my signal generator how do I build one ? I want to connect my signal generator to an audio probe built into a scrap enclosure and then run out into a little practice amp I have.... problem is I'm confused on what to connect and where?.. I have a spare enclosure.. some jacks.. capacitors and an extra set of multimeter probes to use to poke around with? Can someone sketch out or explain how to build one and where to connect everything?
An old probe from a DMM is another option that's a step above using the lead end of the capacitor to probe with.
So...
SIGNAL GEN > CIRCUIT INPUT (or a looper pedal, or strum strum strum strum...)
AUDIO PROBE > AUDIO-DEVICE (headphone amp & headphones or guitar amp or radio speaker, computer speaker in etc...
Proceed to probe the circuit, poke the probe tip to component leads/solder-nibs along the audio path, you will get audio through the listening device up to the point you have a failed component / broken trace / whatever's wrong.
I like to bounce back and forth between the beginning and end of the circuit because it's a PITA to probe all the way from the beginning only to find the problem is at the very end and vice versa. Like eating a sub-sandwich by taking an alternating bite from each end until you reach the middle and it all falls apart...
Simple Audio Probe / Signal Injector (AF): In building and troubleshooting your DIY audio circuits there is often need to probe the leads or components for the signal path or / and inject signal to the audio path. The simplest way is to use aligator clips and a capacitor and hook it to an am…
So, I’m thinking as my next project which will help future projects is to build an audio probe box.
It would be a 1590a with an input, output, and 9v jack. There would be a multimeter probe with a 100nf capacitor attached to the output jack, alligator clips for the power to the board, and a separate clip from the guitar input.
I’m thinking this could work. Now I have to figure out how to keep the cables nice when not using it. Maybe installing a handle or something to wrap the cables around?
Anyone build something like this before? Does this sound reasonable? I’m sick of my workbench...
I just "build" this high end audio probe (100nf) on the tip.
I first tested on a working pedal because every article in the Universe says to use the other wire (red-then-black-alligator in my case to GROUND) and I was not sure about what is ground... (see my level? )
Got a loop going in so I don't have to touch a guitar and started using the probe on R1, C1, C2, R2,R3, C104...
Took me forever to get around to probing because it seemed ... I don't know, above my skill level or something.
It's FAR easier than you'd think. Now I usually just use my Protoboard Mini for all the connections and a long jumper wire for the probe, throw the board or pedal on/next-to the mini-breadboard and feeding it with a looper or some music from my laptop.
Ah... makes more sense now.. for some reason I thought the probe setup would be in front of the pedal... I was thinking backwards.... I think I got it now..... I built a dud this week and it's time to troubleshoot because everything looks spot on and I'm getting absolutely no signal when switched on...
So...my preferred method of doing things is to make things as difficult as possible.
So I haven't built an audio probe: I've built fifty.
Once for each time I need to troubleshoot a circuit. Jack? Check. Jumpers? Check. Signal generator? Check. Cap of random tenths of a uF value? Check. Muttering to self about pain in the ass goddamned piece of fuck...? Check.
A small added point - also you may want to set the output level of your signal generator to match that of your guitar output, which you could measure with a high-impedance ac voltmeter. Rough expected range might be 10s of mV to perhaps 100-200 mV for high output pickups. This way you will measure behavior of the circuit in accordance with how it would act when connected to your guitar. This is particularly helpful when used with an oscilloscope, to see where distortion appears within the circuit (when using sine waves) and/or where equalization occurs (by using sine waves w/ different freqs, or when using a square wave signal), etc.
I like to bounce back and forth between the beginning and end of the circuit because it's a PITA to probe all the way from the beginning only to find the problem is at the very end and vice versa. Like eating a sub-sandwich by taking an alternating bite from each end until you reach the middle and it all falls apart...
This is basically the approach I take when I’m troubleshooting at work (maintenance Electrician is my day job) -
Divide the circuit in half, figure out if the problem is in the 1st or 2nd half, then keep dividing it into half sections until you locate the fault.
For audio probing, I just record a little strumming into my trusty old EHX 2880. It’s (slightly) less annoying than listening to a continuous sine wave or whatever
Ah... makes more sense now.. for some reason I thought the probe setup would be in front of the pedal... I was thinking backwards.... I think I got it now..... I built a dud this week and it's time to troubleshoot because everything looks spot on and I'm getting absolutely no signal when switched on...
Yeah, I flooded you with info, sorry 'bout that — but you never know what "clicks" 'cause everybody learns differently.
CyberCow's post for the win. He did as you requested, showing how SIMPLE a probe could be.
However, just a pic of the apparatus doesn't show the "how" — which is why I included some vids.
The probe itself replaces the lead/cable to the amp, don't even plug anything into the output jack:
)
