Topic: CMC4U Blue Dot

[frogger]

A friend of mine has a pair of these, not matched but consecutive serial numbers with consecutive MK41's.  I realize these use the 12V power but he also has a battery box that provides a line level signal (RCA's out).  Are there any negatives to these mics or this setup?  He's lending them to me to use at Greyfox next weekend with the possibility of me purchasing them at some point in the future.  I'd appreciate any thoughts anybody has on these.  These will be run into my D50.  Any suggestions on what a fair price for both of us would be or is this part better asked in the Yard Sale?  Thanks.

Chuck

[0vu]

From the Schoeps catalogue:

CMC “+5dB”

(Formerly marked with a blue dot.)
The sensitivity of a microphone using this type of microphone amplifier is 5 dB higher. The signal-to-noise ratio of the microphone itself remains nearly unchanged. The maximum sound pressure level the microphone can then accept is reduced by 5 dB.
The risk of overloading the input of the following device when high sound pressure levels are encountered is also increased.
This version might be chosen in order to raise the microphone's signals above the noise level of the equipment to which it will be connected, and/or for working with sounds that occur mainly at low levels.

So if you think that the higher output and reduced max SPL handling might be a problem with your gear, or the kind of use to which you'll put them, then you might want to look elsewhere, otherwise, they're fine. The capsules are probably unmodified (?) and you could always change the bodies out later if they prove to be a problem. You've got the chance to check them out before committing to buy them so you should be ok.

[frogger]

So if you think that the higher output and reduced max SPL handling might be a problem with your gear, or the kind of use to which you'll put them, then you might want to look elsewhere, otherwise, they're fine. The capsules are probably unmodified (?) and you could always change the bodies out later if they prove to be a problem. You've got the chance to check them out before committing to buy them so you should be ok.

Thanks for your research.  I will predominately be recording bluegrass and the chance to check them out lasts pretty much until I make a decision as my friend doesn't use them anymore.  The capsules are not modified, everything was bought new by my buddy back in the late 80's.  Not sure who built the battery box but these were used with a D5 cassette recorder and then he moved on to the PCM/Betamax setup before DATs had been invented or at least made available to the general public.  I waited for the DATs before I moved from the D5.  We did a lot of taping in those days.  Ok, now I'm moving into the ancient history of us old guys. 

[Matt Quinn]

I run these bodies. FWIW, they can be run off any 48v phantom source with an adapter like this:

http://www.bhphotovideo.com/c/product/275819-REG/PSC_FPSC0010A_A4812_48V_to_12T.html

I actually put mine up for sale recently, was looking for $850 for the pair along with the 48>12 adapters.

I've run them in plenty of very loud situations with no noticeable distortion.

[NOLAfishwater]

if you are primarily taping bluegrass, you might want to pick up a pair of cards or omnis as well.

[frogger]

if you are primarily taping bluegrass, you might want to pick up a pair of cards or omnis as well.

The cards will come later.  Just gotta start with what I've got readily available now.

[frogger]

I run these bodies. FWIW, they can be run off any 48v phantom source with an adapter like this:

http://www.bhphotovideo.com/c/product/275819-REG/PSC_FPSC0010A_A4812_48V_to_12T.html

I actually put mine up for sale recently, was looking for $850 for the pair along with the 48>12 adapters.

I've run them in plenty of very loud situations with no noticeable distortion.

Thanks for the info.  When my buddy gave me the mics he gave me some short cables that he said needed to be run inline in order for the mics to work.  Don't know the output of the battery box he gave me but I guess I'll have to look into that.  Perhaps those short cables do the same job as the converters on B&H.  Glad to hear you never had any problems with distortion at higher levels.

[StuStu]

I run these bodies. FWIW, they can be run off any 48v phantom source with an adapter like this:

http://www.bhphotovideo.com/c/product/275819-REG/PSC_FPSC0010A_A4812_48V_to_12T.html

I actually put mine up for sale recently, was looking for $850 for the pair along with the 48>12 adapters.

I've run them in plenty of very loud situations with no noticeable distortion.

Thanks for the info.  When my buddy gave me the mics he gave me some short cables that he said needed to be run inline in order for the mics to work.  Don't know the output of the battery box he gave me but I guess I'll have to look into that.  Perhaps those short cables do the same job as the converters on B&H.  Glad to hear you never had any problems with distortion at higher levels.

What brand/model of battery box do you have to power the Schoeps? The more info...the better.    

[frogger]

What brand/model of battery box do you have to power the Schoeps? The more info...the better.    

All I know is it was custom built for my buddy.  Possibly by Doug and/or Jim Oade.  We had a lot of contact with them back then.  They came up to tape the Philly Folk Fest with us one year and I think they may have come up for one of the Jorma Kaukonen shows we put on.  The only info on it is a date, 4/20/90.  I'll have to check with my friend to see if he can tell me any more about the box.

[lino]

I run these bodies. FWIW, they can be run off any 48v phantom source with an adapter like this:

http://www.bhphotovideo.com/c/product/275819-REG/PSC_FPSC0010A_A4812_48V_to_12T.html

a warning about these PSC adapters
I`ve got 2 of them and to my surprise they put out +48V,You can check that your self with a DMM,
they DO convert Phantom to T-parallel power but they DO NOT step down the voltage down to 12V
this might not be an instant threat to new microphones but is VERY risky with older sennheisers and neumanns (dont know about schoeps) cause those mikes use 10V tantal caps in their power section and those tantals are very very sensitive

[frogger]

Thanks for the warning about the converters.  The setup from my friend includes some "special" cables (foot-long XLRs) that need to be inline between the mics and box.  We are now trying to get more details.  Doesn't look like Oades built it but they may have provided the design.

[DSatz]

Schoeps microphone amplifiers (bodies) don't come in matched pairs; Schoeps only matches capsules, not microphones or bodies. As long as two CMC amplifiers are of the same type, in good working order and both set up the same way (e.g. both +5 dB, or else both not), they should match within a fraction of a dB.

CMC 4-- amplifiers were designed for parallel powering, not phantom powering. The two systems are incompatible, and hardly anyone buys this type of equipment new any more. 30-35 years ago, though, parallel powering used to be widespread among film and video sound recordists; it was available from Nagra portable tape recorders, and Sennheiser shotgun microphones (actually, all Sennheiser condenser microphones for a long time) used that powering method. But by around 1970 Nagra and, some years later, Sennheiser gave in to the reality that the pro audio market had decisively chosen phantom powering.

Unfortunately there is no legitimate way to convert a CMC 4 amplifier to, say, a CMC 3 or CMC 5 for phantom powering. You either need to use an actual power supply designed for parallel powering (the standard voltage is in the range of 10 -12 Volts DC) or one of those adapters, if it's a good one. If it throws 48 Volts at the microphone, though, something is wrong; don't use it.

Also, the stock CMC 4-- amplifier follows DIN standard powering polarity while Nagra and Sennheiser chose the opposite polarity; for compatibility with Nagra recorders, Schoeps made a special version of the CMC 4-- amplifier called the CMC 4k (or CMC 4Uk with an XLR connector). If there is an adapter cable that's needed between the mike and the power supply, and if it has XLRs on both ends, you may find that it is inverting polarity for that reason. Or not; you'll have to check somewhat carefully.

--best regards