Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

Reducing 48 volts Phantom Power to 5 to 8 volts for mic input

Reducing 48 volts Phantom Power to 5 to 8 volts for mic input

Reply

  #1  
Old 04-04-13, 04:42 PM
Member
Thread Starter
Join Date: Apr 2013
Location: United States
Posts: 3
Received 0 Votes on 0 Posts
Reducing 48 volts Phantom Power to 5 to 8 volts for mic input

I have a Axis P8221 network module that has a microphone input that is powered with 48 volt DC phantom power (two pins). The trouble is the condenser mic element I need to hook it to is 1 to 10 VDC max (so 5ish volts?) and 0.3mA max (two pins).

In all the hunting I've done I have seen folks recommend Zener Diodes and Resistors but these diagrams seem to be for XLR connectors (three pins). I need something small and I am guessing just sitting on the positive side of the mic input to reduce to the proper voltage/amperage. I could really use a part recommendation (from radio shack maybe?) of what to get. Any advice is greatly appreciated! I'm not an electrical engineer by any means.
 
Sponsored Links
  #2  
Old 04-04-13, 04:52 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,967
Received 3 Votes on 3 Posts
Welcome to the forums! It shows Audio 1 to use Phantom power and Audio 2 for condenser mics. Is that what you gather, too? I run a 48 channel Yamaha at our church and sometimes forget to disengage phantom power, but seldom makes a difference unless you actually need it engaged. Of course we are using XLR connections, too.
 
  #3  
Old 04-04-13, 09:04 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 522 Votes on 491 Posts
48 volt phantom power is kind of an interesting thing. It rarely is anywhere near 48 volts.

With your unit...if you are using a cartridge like shown in the pics below ..... you shouldn't need to do anything to connect the mic element. There is a polarity to the cartridge that must be followed.

Examples of supported audio equipment for your unit:

Audio 1 input (3.5 mm audio jacks)
Electret microphone, unbalanced dynamic microphone, line in.

Audio 2 (terminal connector)
Balanced microphone
 
Attached Images   
  #4  
Old 04-05-13, 07:01 AM
Member
Thread Starter
Join Date: Apr 2013
Location: United States
Posts: 3
Received 0 Votes on 0 Posts
Thanks for the replies! I appreciate it.

Using Audio 1 will be a last resort. The unpowered mics don't have much pickup and this is connecting to a PNL-CIS4 panel outside.

I talked to Digitial Acoustics support and sales department prior to purchasing and it was thought to work with the Axis. At first I was told that the mic did not need Phantom power. After I was unable to make the mic work, I was told it did need Phantom power. After I enabled Phantom power and it still didn't work, I asked about the 48V Phantom power they told me I burned out the mic and it was my fault.

I picked up another element from Radio Shack with similar specs, but I didn't want to make the same mistake and kill another mic (if Digital Acoustics even knows what they are talking about).

This should be dead simple with only two pins to connect and triple checking for correct polarity. I get a deep hum when I plug the unit together, but nothing else.
 
  #5  
Old 04-05-13, 10:30 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 54,685
Received 522 Votes on 491 Posts
Did you observe polarity like I mentioned in my previous post ?

One pin should have a bridge to the shell of the cartridge. That will be ground.

Are you trying to use that outside call station to power this device like a microphone ?
I'm trying to figure out what you are doing.
 
  #6  
Old 04-09-13, 08:35 AM
Member
Thread Starter
Join Date: Apr 2013
Location: United States
Posts: 3
Received 0 Votes on 0 Posts
I found what I needed to make this work. ETS manufacturers an inexpensive 48V phantom powered mic for a whopping $35 (compared to $500 for the Axis one).
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: