Calrec CM654a Mystery

[nsureit]

I just acquired this vintage (60s-70s era) microphone from a friend. It is presenting a mystery of sorts.

It seems to work well, but needs a lot of gain. I've been doing research, and I can find a bunch of info on the CM654d, but NOTHING about the CM654a! A condenser mic should not work at all without phantom power, but the 654a provides a signal unpowered. If I add phantom power, it gives it just a tiny boost, not much. To get a good signal, I have to max out the gain on my interface. It sounds fine. I have not connected it yet to my Trident 80B preamp.

I read where these Calrecs are unbalanced, and require a proprietary power supply or a custom built adapter cable in order to use phantom power. This 654a works just fine with a standard XLR. I'm emailing anybody I can find that posted anything about CM654s in the last 40 years!

Any expert here know anything about the Calrec CM654a?

 

[witzendoz]

Not quite, but you might find this interesting

alan.

PS, the technical sheet mentions batteries, I did wonder if you had an almost flat internal battery?

PSS, Just found this.

 

[nsureit]

Not quite, but you might find this interesting

alan.

PS, the technical sheet mentions batteries, I did wonder if you had an almost flat internal battery?

PSS, Just found this.

Thank you for the reply. I found those articles/posts, and they provided a good background for the Calrec 600 series. However, I think the key right now is to find out the difference between a CM654D and my 654A.

I sent emails to Saturn Sound and Hebden Sound (successor to Calrec microphones), and hope to get a response.

Will keep this thread updated.

 

[nsureit]

Received a reply from David Anderson at Hebden Sound in the UK. They will inspect and analyze my 654A. They will repair or modify it to work with standard phantom power via XLR.

Thanks for the help! It did not take long to find the right source for getting this mic to work properly. Will probably cost me a bloody fortune, but, what the hell!