R/E/P Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 [2]  All   Go Down

Author Topic: Phantom Power Inline Blocker?  (Read 12815 times)

Martin Kantola

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 362
Re: Phantom Power Inline Blocker?
« Reply #15 on: August 21, 2007, 12:39:53 PM »

Yes, Jon is right, another transformer with the same bandwidth as the one already in the mike won't help much.

Thanks for explaining what the sine wave test was for, makes perfect sense now Smile

Still stuck on analyzing the cause of danger without even a patch bay here...

The 6k8 phantom resistors (with a 48V source between them) won't help the fact that if we somehow get a DC voltage differential on the pre-amp side of the capacitors, it would also turn up on the mike side of the caps. And still thinking, no voltage difference equals no harm.  

Martin
Logged

ssltech

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 4780
Re: Phantom Power Inline Blocker?
« Reply #16 on: August 22, 2007, 06:11:37 PM »

You can use two pretty large caps in an inline-blocker, and two bleed-to-ground resistors on the microphone side of the caps.

OR...

An alternative inline blocker, with a transformer in it.

Plug the blocker in and wait a minute or two if it's the cap/resistor variety. Then plug in the mic.

Doing this, I cannot conceive of a single circumstance or situation where it is AT ALL POSSIBLE for phatom power to damage the microphone, assuming that the phantom power remains constantly-present.

If you can't reasonably rely on the phantom being constant, (easily-nudged phantom switches, power cuts etc) then all bets are off, and you are risking your ribbons just by being in that room! Wink

That's my take on it, anyhow!

keith
Logged
MDM (maxdimario) wrote on Fri, 16 November 2007 21:36

I have the feeling that I have more experience in my little finger than you do in your whole body about audio electronics..

mshilarious

  • Jr. Member
  • **
  • Offline Offline
  • Posts: 70
Re: Phantom Power Inline Blocker?
« Reply #17 on: August 22, 2007, 10:06:12 PM »

That will work, but you did assume phantom power was constantly present.  In a controlled environment (that is, the engineer doesn't do anything stupid), that's fine.  But then a similarly diligent engineer doesn't need phantom blocking in the first place.  I agree the best solution is paying attention to what you are doing!

From the mic manufacturer's point of view, you have to assume the customers are going to do all sorts of crazy things with patchbays and jiggling cable connectors or simply tripping over them and dislodging a cable.  That removes the constant phantom assumption.  If you can't protect against those mishaps, there is little point in adding circuitry to your microphone.
Logged
Pages: 1 [2]  All   Go Up
 

Site Hosted By Ashdown Technologies, Inc.

Page created in 0.088 seconds with 20 queries.