48V phantom supply for mic - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 6th August 2012, 07:20 PM   #1
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Default 48V phantom supply for mic

48V Phantom Feed Supply for Microphones

Is it appropriate to connect the grounds from Figures 1 and 2? In figure 2, however, the ground would also be connected to "pin 1" on the XLR connections, which will eventually be connected to chassis/earth.

I guess what I'm asking is if it's safe to directly connect earth to the ground on the voltage doubler supply without any adverse effects.
  Reply With Quote
Old 6th August 2012, 07:25 PM   #2
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Moved to Instruments and Amplifiers - hopefully you are more likely to get a good answer here. (Some of these guys are certainly using phantom powered mics, that's my theory at least.)
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 6th August 2012, 07:26 PM   #3
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Second question - on Figure 4 on this datasheet, http://www.ti.com/lit/ds/symlink/ina217.pdf, regular diodes to the supply rails are used, whereas on the westhost article, zeners are used. Which is preferable, or should both be used?
  Reply With Quote
Old 6th August 2012, 07:30 PM   #4
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Third question - Figure 8 on Elliott Sound Products - Linear Power Supply Design shows a voltage doubler rectifier. If I put 24VAC into this I should get around 65VDC?
  Reply With Quote
Old 6th August 2012, 07:38 PM   #5
Tajzmaj is offline Tajzmaj  Slovenia
diyAudio Member
 
Join Date: Mar 2011
Location: Ljubljana
As long as you have separate winding on transformer just for phantom power.
I checked link and it's Rod Elloiott's project which means it's 100% fully functional. If you want you can replace voltage doubler only by gretz and capacitor and than optionally some 47-100E resistor and one more capacitor. Transformer voltage should be than some 50VAC and capacitors should be 100V types. And please it is very important to make the whole circuit not just power supply. Phantom powering circuit (fig.2) is essential especially those 2 6K8 resistors. Without it you will burn something.
Cheers, Taj
  Reply With Quote
Old 6th August 2012, 07:41 PM   #6
Tajzmaj is offline Tajzmaj  Slovenia
diyAudio Member
 
Join Date: Mar 2011
Location: Ljubljana
Diodes. It is different connection. Check again.
  Reply With Quote
Old 6th August 2012, 07:43 PM   #7
Tajzmaj is offline Tajzmaj  Slovenia
diyAudio Member
 
Join Date: Mar 2011
Location: Ljubljana
You should get transformer voltage x2 and that value x1.41..
At least in theory and of course without any load.
Cheers
  Reply With Quote
Old 6th August 2012, 07:46 PM   #8
Tajzmaj is offline Tajzmaj  Slovenia
diyAudio Member
 
Join Date: Mar 2011
Location: Ljubljana
About diodes. One question. Which mic preamp you want to use? If you want to build that TI thing than stick to schematic from datasheet.
  Reply With Quote
Old 7th August 2012, 12:35 AM   #9
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Yes, for the preamp I would like to use the suggested schematic for the INA217.
  Reply With Quote
Old 7th August 2012, 12:44 AM   #10
Tajzmaj is offline Tajzmaj  Slovenia
diyAudio Member
 
Join Date: Mar 2011
Location: Ljubljana
If you think that it is ok than stick to original schematic.
there are also other good ,,on chip,, solutions from THAT corporation. And of course some nice all discrete SS vintage things. It depends what's the purpose.
Cheers
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Diy Mic preamp with 48v phantom power cheeseburgerjoe Parts 12 16th September 2010 11:33 PM
xlr and 48v phantom power to pc oublie PC Based 7 14th November 2009 03:40 PM
+/-15V from +48V Phantom Pilbromatic Parts 4 9th August 2009 05:46 AM
sounds silly .. but do i need a 48v phantom power ? Ahmad_tbp Solid State 8 3rd February 2007 10:36 AM
48v phantom / resistor is way hot ! redrabbit Solid State 12 15th February 2006 08:14 AM


New To Site? Need Help?

All times are GMT. The time now is 08:26 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2