Jump to content


Photo
- - - - -

Western Electric electret mic?


  • Please log in to reply
4 replies to this topic

#1 ThoughtPhreaker

ThoughtPhreaker

    BinRev veteran

  • Members
  • 1,213 posts
  • Gender:Male

Posted 09 March 2014 - 07:12 PM

So I had a bit of a curiosity I was hoping someone could answer - is there a feasible way to retrofit a 2500 set or something like it with an electret mic? I know a lot of the drug store phones have them right out of the box, but is there a simple way to insert a preamp into the phone? As much as I like the carbon microphone sound, every so often, it'd be nice to have something smoother sounding.



#2 systems_glitch

systems_glitch

    Dangerous free thinker

  • Moderating Team
  • 1,636 posts
  • Gender:Male

Posted 09 March 2014 - 09:09 PM

Probably, should have talk battery on the mic lines when it's off-hook. IIRC, electrets sink current to ground using a FET through a source resistor and you pass the AC through a coupling cap, pretty much just like an AC coupled triode tube stage. You may be able to just slap one in there with the right rating and polarity.



#3 JmanA9

JmanA9

    SUPR3M3 31337 Mack Daddy P1MP

  • Members
  • 434 posts
  • Location:NPA 724

Posted 10 March 2014 - 09:54 AM

There is a British website that sells electret button cartridges that fit WE phones.  I can't seem to find it though.

 

I've found that the newer WE carbon transmitters perform much better than the old ones.  Have you tried one from the '80s?

 

Edit: Looks like Mike Sandman sells an electret microphone that fits 2500 sets through a modified cup.  It doesn't mention anything aobut additional equipment.

 

http://www.sandman.com/parts.html

EMS-94 Electronic Carbon Replacement with High Quality Sound:  $14.95.


Edited by JmanA9, 10 March 2014 - 10:07 AM.


#4 ThoughtPhreaker

ThoughtPhreaker

    BinRev veteran

  • Members
  • 1,213 posts
  • Gender:Male

Posted 10 March 2014 - 08:14 PM

You may be able to just slap one in there with the right rating and polarity.

 

I dunno what it's rated at, but this didn't work with the handset from a Nortel Millennium desk set.

 

Edit: Looks like Mike Sandman sells an electret microphone that fits 2500 sets through a modified cup.  It doesn't mention anything aobut additional equipment.

 

Interesting! I might wind up getting one to take a look. Maybe there's something extra in the cup? It seems like it'd be cheaper to make something that would just work with the current cup. For whatever it's worth, the "take the varistor out of an earpiece and get a dynamic transmitter" idea didn't work for me either. I just ended up with an extra transmitter with really loud battery drops.

 

Can't say I've tried a more recent carbon mic. I ended up unscrewing the transmitter cap to take a look at the date of manufacture on mine. 7/11/1963! It doesn't sound too bad actually, but a change of pace would be nice.

 

For what it's worth, I did find this; http://www.vmarsmanu...Replacement.pdf . Kinda overkill - particularly with pass filters in it, but no reason why the basic idea won't work.



#5 dmine45

dmine45

    Mack Daddy 31337

  • Members
  • 225 posts

Posted 11 March 2014 - 06:38 PM

Wow! I need to get a new transmitter. I have a 2-line COMDIAL phone from the 80s with an F-style (square earpiece/mouthpiece) but it uses a carbon mic. I use it quite a bit but people say the volume is too low. That may solve my problem!






BinRev is hosted by the great people at Lunarpages!