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High-Gain Mic Amplifier - Hard-Wired Input - Anyone SEEN These ?

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  High-Gain Mic Amplifier - Hard-Wired Input - Anyone SEEN These ? c186282 <c186282@nnada.net> - 2026-09-14 02:30 -0400
    Re: High-Gain Mic Amplifier - Hard-Wired Input - Anyone SEEN These ? "Carlos E. R." <robin_listas@es.invalid> - 2026-09-14 09:44 +0200

#91414 — High-Gain Mic Amplifier - Hard-Wired Input - Anyone SEEN These ?

Radio Shack/Realistic USED to sell these ... a small box
with a speaker and really high-gain mic input jack. I'd
put a MAGNETIC pickup on 'em ... used 'em to find noisy
circuits for embedded devices on vehicles. You could
just HEAR the static. Very useful !

Have a newer unit, LOW-gain alas. Can BARELY hear a
thing even on ultra-noisy wiring.

CANNOT find anything quite like the old RS unit.
A lot of 'speaker' things, but mostly intended
for a wireless mic and ridiculously high output.

My damned hardwire PHONE doesn't RING anymore.
They MAY be replacing it with some kind of weird
VOIP device in a few weeks - HOPE it uses my
existing WiFi - have a shitload of 'devices'
that'd have to be re-done otherwise. One or
two might require LADDERS - NOT good for me at
my age and condition !

However MEANWHILE ... my phone DOES know when
the line goes hot, just doesn't RING. It comes
all alive, lights, CID, all the good stuff.

My IDEA was to put on one of those magnetic sensors,
DO have one, on the phone. For sure it'll make
special noises when the electronics come on.
Then I can HEAR a call, even if there's no ring.

The one little amp I have is, alas, NOT very
sensitive. You can hear a LITTLE noise if you
like put it right over a rotating fan or the
like. The old RS unit was MUCH better.

BUT, going pages down on Amazon, doesn't seem to
BE an equiv of the RS unit. Some alts are cheap,
ordered a couple to try, but I have doubts.

Note, IF you remember, the RS unit was a simple
grey box with a little speaker and a mic jack.
Ran on a 9v battery. MAY have been a 9v power
jack too, don't remember. If not, SOLDER !
A 9v Ard power supply should work perfectly.

The big trick is "high gain".

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#91417

On 2026-09-14 08:30, c186282 wrote:
> Radio Shack/Realistic USED to sell these ... a small box
> with a speaker and really high-gain mic input jack. I'd
> put a MAGNETIC pickup on 'em ... used 'em to find noisy
> circuits for embedded devices on vehicles. You could
> just HEAR the static. Very useful !
> 
> Have a newer unit, LOW-gain alas. Can BARELY hear a
> thing even on ultra-noisy wiring.
> 
> CANNOT find anything quite like the old RS unit.
> A lot of 'speaker' things, but mostly intended
> for a wireless mic and ridiculously high output.
> 
> My damned hardwire PHONE doesn't RING anymore.
> They MAY be replacing it with some kind of weird
> VOIP device in a few weeks - HOPE it uses my
> existing WiFi - have a shitload of 'devices'
> that'd have to be re-done otherwise. One or
> two might require LADDERS - NOT good for me at
> my age and condition !
> 
> However MEANWHILE ... my phone DOES know when
> the line goes hot, just doesn't RING. It comes
> all alive, lights, CID, all the good stuff.

My guess is that your phone has a broken bell. Or the equivalent 
circuit. Try to plug another unit.

> 
> My IDEA was to put on one of those magnetic sensors,
> DO have one, on the phone. For sure it'll make
> special noises when the electronics come on.
> Then I can HEAR a call, even if there's no ring.
> 
> The one little amp I have is, alas, NOT very
> sensitive. You can hear a LITTLE noise if you
> like put it right over a rotating fan or the
> like. The old RS unit was MUCH better.
> 
> BUT, going pages down on Amazon, doesn't seem to
> BE an equiv of the RS unit. Some alts are cheap,
> ordered a couple to try, but I have doubts.
> 
> Note, IF you remember, the RS unit was a simple
> grey box with a little speaker and a mic jack.
> Ran on a 9v battery. MAY have been a 9v power
> jack too, don't remember. If not, SOLDER !
> A 9v Ard power supply should work perfectly.
> 
> The big trick is "high gain".
> 


-- 
Cheers,
        Carlos E.R.
        ES🇪🇸, EU🇪🇺.

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