Author Topic: Audio probe  (Read 5000 times)

philmurr

  • Jr. Member
  • *
  • Posts: 31
    • View Profile
Audio probe
« on: December 10, 2016, 09:48:12 PM »
I've been doing some work lately on some faulty sound boards and old drum machines, and found it quite tricky to work out exactly what part of a circuit was faulty.  You can't really use a logic probe to help, and a 'scope can give difficult to understand readings.

I had a look around for an audio probe (which is used to probe parts of a circuit and hear what's going on), but couldn't find one at a reasonable price, so armed with the LM386 amp datasheet I set out to build my own.  A PCB was designed, plus around £7 of components later and I've a working audio probe.

The probe connects to the power supply of the circuit under test (usually the 0V & +12V of the sound section), you just need to plug in a pair of headphones as it doesn't have a built-in speaker.  The sensitivity and volume are adjustable, and you just touch the probe tip to the part of the circuit you want to "listen to".

It helps answer the "is the power amp or some other part of the sound circuit faulty" predicament as it can prove the working bits of a circuit to narrow down to where a fault actually is.

Photos of the one built unit are attached (the probe tip is a nail, until the proper tips I've ordered arrive from China!)

Bare PCBs are available if anyone is interested, £2 each plus postage



Ramakers

  • Jr. Member
  • *
  • Posts: 25
    • View Profile
Re: Audio probe
« Reply #1 on: December 27, 2016, 08:50:03 PM »
Nice job. Looks clean and simple.
Why buy something if you can make it yourself. Thanks for sharing.

Etienne MacGyver

  • ArcadeLifeStyler'
  • ***
  • Posts: 7611
  • The Netherlands
    • View Profile
Re: Audio probe
« Reply #2 on: December 28, 2016, 09:55:33 AM »
Why buy something if you can make it yourself.

Because its awesome that there are people who want to share theyre knowledge at little to no cost.

If i misunderstand your comment (which is possible as you perhaps mean it in a way that he created it himself instead of buying it commercially) i apologize, but it sounded like why buy it from this guy if you can make it yourself.

Ramakers

  • Jr. Member
  • *
  • Posts: 25
    • View Profile
Re: Audio probe
« Reply #3 on: December 28, 2016, 02:53:11 PM »
Why buy something if you can make it yourself.

Because its awesome that there are people who want to share theyre knowledge at little to no cost.

If i misunderstand your comment (which is possible as you perhaps mean it in a way that he created it himself instead of buying it commercially) i apologize, but it sounded like why buy it from this guy if you can make it yourself.
I wasn't being assaulting and when I read it again I see the misunderstanding, I didn't mean making the PCB yourself instead of buying one from the post starter for only £2. I was talking about stuff in general. I highly appreciate people sharing things with those with less means of building things from scratch or want a professional looking tool. And in the £2 aren't any profits I believe.

Etienne MacGyver

  • ArcadeLifeStyler'
  • ***
  • Posts: 7611
  • The Netherlands
    • View Profile
Re: Audio probe
« Reply #4 on: December 28, 2016, 04:01:43 PM »
Ok understood  ;)  ;D 8)

I interpreted your comment wrong  :-X

Ramakers

  • Jr. Member
  • *
  • Posts: 25
    • View Profile
Re: Audio probe
« Reply #5 on: December 28, 2016, 04:53:14 PM »
Ok understood  ;)  ;D 8)

I interpreted your comment wrong  :-X
of topic:
Engels is dan ook niet mijn moedertaal, de jouwe ook niet denk ik. (English is not my native language, and it isn't yours, I think.)

smarty

  • Jr. Member
  • *
  • Posts: 99
  • Hampshire, UK.
    • View Profile
    • Jumpnfire.com
Re: Audio probe
« Reply #6 on: December 28, 2016, 08:50:08 PM »
I recently made up one of these boards from Phil, I used parts I already had spare.

I still need to case it up, but it does work well as is.

www.jumpnfire.com

MOST WANTED CABS:

Etienne MacGyver

  • ArcadeLifeStyler'
  • ***
  • Posts: 7611
  • The Netherlands
    • View Profile
Re: Audio probe
« Reply #7 on: December 30, 2016, 11:56:36 AM »
Ok understood  ;)  ;D 8)

I interpreted your comment wrong  :-X
of topic:
Engels is dan ook niet mijn moedertaal, de jouwe ook niet denk ik. (English is not my native language, and it isn't yours, I think.)

Inderdaad  ;D ;D