Topic: schoeps cmc4u-k powering issues

[Shawn]

who does schoeps repair in the US

[ljramsey]

who does schoeps repair in the US

Hey Shawn - you picked up some Schoeps??

[Shawn]

yep. I thought they may have been damaged, but after doing some more research I think the mics are fine. I think the problem is that the phantom circuit on the r-4 only allows for an 8ma draw and the mics need 9ma. never in my life did I consider that this could be an issue. I'm going to take them down to a local pro audio dealer today and test them on some other pre-amps to see if that is the problem.

[Brian Skalinder]

FWIW, I had no problems running MKx / KC5 / CMC6 using phantom on my R-4.

What symptoms are you experiencing?

[George2]

Are those the t-powered? Some older t-powered mikes used in film dialog had a 'red dot' mod. They will not work with standard t-powering. You need to change 2 wires around on the
connector, but I can't remember which ones. Some t-powered supplies have a switch built in to do this. Notice on the Denecke PS-T supply it has a red dot switch. Some Nagra recorders were wired differently. This could be the problem. I don't think it's a too low of current problem. I'd contact the previous owner and ask what he powered them with.

http://www.denecke.com/Products/Audio%20Accessories/audioaccessories.htm#PST

[Shawn]

FWIW, I had no problems running MKx / KC5 / CMC6 using phantom on my R-4.

What symptoms are you experiencing?

the current draw is different for the cmc6 and the cmc4. the cmc6 only draws 4ma and the cmc4 draws 9ma. The R-4 can only give 8ma thus my concern that I'm not getting enough juice.

the symptoms... no levels at all when running mic in with the gain at full bore.

[Shawn]

Are those the t-powered? Some older t-powered mikes used in film dialog had a 'red dot' mod. They will not work with standard t-powering. You need to change 2 wires around on the
connector, but I can't remember which ones. Some t-powered supplies have a switch built in to do this. Notice on the Denecke PS-T supply it has a red dot switch. Some Nagra recorders were wired differently. This could be the problem. I don't think it's a too low of current problem. I'd contact the previous owner and ask what he powered them with.

http://www.denecke.com/Products/Audio%20Accessories/audioaccessories.htm#PST

yes they are t-powered mics and they are some times referred to as the "blue dot bodies" partially because they have a blue dot which I believe signifies that they are standard t-power as opposed to red dot t-power. the previous owner powered them with a schoeps bz9 t-power supply. I felt it was unnecessary, bulky, required special cables, and would be another unit to have to power in the field. so I passed on purchasing it in favor of the psc 48v to 12v adapters because I read numerous accounts in which people were using them with the cmc4 bodies successfully.

[Shawn]

Are those the t-powered? Some older t-powered mikes used in film dialog had a 'red dot' mod. They will not work with standard t-powering. You need to change 2 wires around on the
connector, but I can't remember which ones. Some t-powered supplies have a switch built in to do this. Notice on the Denecke PS-T supply it has a red dot switch. Some Nagra recorders were wired differently. This could be the problem. I don't think it's a too low of current problem. I'd contact the previous owner and ask what he powered them with.

http://www.denecke.com/Products/Audio%20Accessories/audioaccessories.htm#PST

please allow me to eat my words a little here... I just got off the phone with the folks at redding audio and he told me the mics are red dot powered. he said open up the barrel adapters swap pins two and three and it should work.

still concerned about th 8ma limitation of the r4 and 9ma draw of the bodies, but I'll burn that bridge when I get to it

[Brian Skalinder]

the current draw is different for the cmc6 and the cmc4. the cmc6 only draws 4ma and the cmc4 draws 9ma. The R-4 can only give 8ma thus my concern that I'm not getting enough juice.

Ahhhhh...didn't know they were CMC4s.

[Shawn]

sorry should have been more specific in my post.

[George2]

They should run fine on your power. Blue dot is a mod giving the Schoeps about 5db more gain/output. You are gonna like them!

[Shawn]

So the guys at redding audio told me that the cmc4u and the cmc4u-k are powered differently. the cmc4u uses standard t-power and the cmc4u-k uses "red-dotted" t-power. Red dotted t-power basically is the same as standard t-power except the positive and negative signals are swapped. Basically all I needed to do was swap the wires for pins 2 and 3 in my power adapters and it should work fine. I did some research this afternoon, and found that hosa has an XLR barrel adapter that does that. I went down to GC and picked up a pair. I threw them in line with the power adapters and everything works fine now. No problems with the 8ma of the r4. I've learned more about mic power in the last two days than i ever thought I would.

thanks to everyone. +T to the thread.

here is a link to some useful info on t-power and the differences between red dot and standard t-power:
http://www.equipmentemporium.com/reddot.htm

and here is a link to the hosa polarity cross adapters: http://www.midi-store.com/HOSA-GXX-195-POLARITY-CROSS-REVERSE-PHASE-XLR-F-TO-XLR-M-p-16955.html