Question about passing phantom through splitter

clarocque · 27th January 2010

Hello,

I have a 48 channel CBI splitter with two fans. One with direct out and the other with transformers and ground lifts. My questions is this....

Lets say the FOH does not have phantom or does not have enough channels to power two audience mics that I add to the live recording. I was thinking I could take the direct outs for those 2 mics to my presonus pre-amp (for recording) vs. the iso feed.

What I am curious about it is what happens if I add phantom power to 2 channels that are in the iso fan? Will it damage the transformer or simply just get ignored? I do not need it to work but I do not want to cause any damage.

BTW... My preamps power 4 phantoms at a time.

Another option would be to add a 2 channel phantom supply separate.

Thoughts?

Chris

mixedupsteve · 27th January 2010

Quote:

Originally Posted by clarocque

Hello,

I have a 48 channel CBI splitter with two fans. One with direct out and the other with transformers and ground lifts. My questions is this....

Lets say the FOH does not have phantom or does not have enough channels to power two audience mics that I add to the live recording. I was thinking I could take the direct outs for those 2 mics to my presonus pre-amp (for recording) vs. the iso feed.

What I am curious about it is what happens if I add phantom power to 2 channels that are in the iso fan? Will it damage the transformer or simply just get ignored? I do not need it to work but I do not want to cause any damage.

BTW... My preamps power 4 phantoms at a time.

Another option would be to add a 2 channel phantom supply separate.

Thoughts?

Chris

The transformers will only pass ac and phantom is dc so it will be blocked. No problem with that. Use the direct to power your phantom mics.

clarocque · 27th January 2010

Quote:

Originally Posted by mixedupsteve

The transformers will only pass ac and phantom is dc so it will be blocked. No problem with that. Use the direct to power your phantom mics.

OK thanks Steve. So if I hook up 4 mics to to the phantom powered pre-amp and run 2 via direct split and 2 via iso split, the 2 channels will just be blocked (with no damage to splitter or mics?) and the 2 on the direct side will send power to the mics as designed?

I guess I just want to verify that sending phantom power to the splitter via the isolated split will NOT damage the transformer.

Thanks

mixedupsteve · 27th January 2010

Quote:

Originally Posted by clarocque

OK thanks Steve. So if I hook up 4 mics to to the phantom powered pre-amp and run 2 via direct split and 2 via iso split, the 2 channels will just be blocked (with no damage to splitter or mics?) and the 2 on the direct side will send power to the mics as designed?

I guess I just want to verify that sending phantom power to the splitter via the isolated split will NOT damage the transformer.

Thanks

No it wont hurt the transformers. Why don't you just take all the directs and give the FOH the iso side?

clarocque · 28th January 2010

Ideally that would be the best way Steve... but from what I have read I will run in to an Engineer who wants the directs so I wanted to be prepared.

Thanks for the advise.

Chris

**Remoteness** · 6th February 2010

The simple phantom power mindset should be as follows...
Whoever provides the phantom power gets the direct output of the splitter.

If FOH gets the direct and cannot power your extra audience mics, you could simply provide an inline power supply for those mics or you could have a separate snake just for the those mics.

Just like Steve stated, XFMRs only pass ac, so 48V DC will be blocked by the XFMR.
Using the direct out to power your extra phantom mics should not be a problem just as long as all the grounds (pin one) are individually grounded and not bussed together like some older systems were. You don't want to be tied into the FOH system ground in anyway for the obvious reasons.

clarocque · 7th February 2010

Thanks Steve,

I did put ground lifts on each channel and had it changed so I can pick and choose where the directs go.

So I can send some directs to FOH and some Directs to recording as needed.

Thanks for the information.

Chris

Maur Bighley · 21st February 2010

Glad I did a search! Just the answer I needed for my question I was about to post.

Thanks guys!

27th January 2010	#1
clarocque Gear nut Joined: Apr 2009 Location: Vermont Posts: 120 Thread Starter	Question about passing phantom through splitter Hello, I have a 48 channel CBI splitter with two fans. One with direct out and the other with transformers and ground lifts. My questions is this.... Lets say the FOH does not have phantom or does not have enough channels to power two audience mics that I add to the live recording. I was thinking I could take the direct outs for those 2 mics to my presonus pre-amp (for recording) vs. the iso feed. What I am curious about it is what happens if I add phantom power to 2 channels that are in the iso fan? Will it damage the transformer or simply just get ignored? I do not need it to work but I do not want to cause any damage. BTW... My preamps power 4 phantoms at a time. Another option would be to add a 2 channel phantom supply separate. Thoughts? Chris

6th February 2010	#6
Remoteness Super Moderator Joined: Aug 2002 Location: NYC Posts: 7,405	The simple phantom power mindset should be as follows... Whoever provides the phantom power gets the direct output of the splitter. If FOH gets the direct and cannot power your extra audience mics, you could simply provide an inline power supply for those mics or you could have a separate snake just for the those mics. Just like Steve stated, XFMRs only pass ac, so 48V DC will be blocked by the XFMR. Using the direct out to power your extra phantom mics should not be a problem just as long as all the grounds (pin one) are individually grounded and not bussed together like some older systems were. You don't want to be tied into the FOH system ground in anyway for the obvious reasons. __________________ Steve Remote AuraSonicLtd.com the home of ASL Mobile & Location Production Remoteness on the Linkedin Network What about my Facebook Profile? Remoteness on Myspace

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread starter	Forum	Replies	Last Post
Mic splitter ground lift kills phantom 48V... Why?	XLR2XLR	Remote Possibilities in Acoustic Music & Location Recording	8	14th June 2010 01:57 AM
Question on Mic Splitter	sissybum	Remote Possibilities in Acoustic Music & Location Recording	11	12th May 2009 04:24 PM
Signal Splitter Question	tubeman	So much gear, so little time!	0	10th August 2006 12:44 AM
Splitter question	OScope	Remote Possibilities in Acoustic Music & Location Recording	3	10th December 2005 06:51 PM
Splitter Snake Question	Tone Laborer	Remote Possibilities in Acoustic Music & Location Recording	38	23rd June 2005 05:40 PM

28th January 2010	#5
clarocque Gear nut Joined: Apr 2009 Location: Vermont Posts: 120 Thread Starter	Ideally that would be the best way Steve... but from what I have read I will run in to an Engineer who wants the directs so I wanted to be prepared. Thanks for the advise. Chris

7th February 2010	#7
clarocque Gear nut Joined: Apr 2009 Location: Vermont Posts: 120 Thread Starter	Thanks Steve, I did put ground lifts on each channel and had it changed so I can pick and choose where the directs go. So I can send some directs to FOH and some Directs to recording as needed. Thanks for the information. Chris

21st February 2010	#8
Maur Bighley Gear nut Joined: Oct 2008 Location: Central, NJ Posts: 90	Glad I did a search! Just the answer I needed for my question I was about to post. Thanks guys!