Poor man's USM69?

[RuudNL]

For years I have been planning to build a stereo microphone with a rotatable microphone capsule.
The main reason I never realized this were the mechanical difficulties in doing this properly.
By coincidence I found a microphone that already meets most of my requirements:

- Affordable (Requirement number one!)
- Two double sided edge terminated microphone capsules
- Separate pattern selection per microphone system (Omni, figure-8, cardioid)
- 10 dB pad + low cut filter per microphone system
- Top capsule rotatable from 0 to 90 degrees

This microphone could be used for X-Y, M-S and Blumlein recordings.
The microphone uses a modified Schoeps circuit and a DC converter for the polarisation voltage.
Although I thought about modifying, the quality is adequate for my needs.
There are a few things that I have changed:
- The capsule polarisation voltage was about 40 volts, I have raised that to 50 volts.
- The wiring of the 5-pin XLR connector was a bit strange. (Is there even a standard for stereo microphones?)
The original connection was: Pin 1+2 microphone 1, pin 3 shield/'ground', pin 4+5 microphone 2.
Since another stereo microphone that I own has a different connection, I have changed this to: Pin 1 shield/'ground', pin 2+3 microphone 1, pin 4+5 microphone 2.
The only obvious improvement are the headbaskets.
These headbaskets are single layer mesh, but do not provide enough shielding for electrical fields.
I have added a second layer of mesh and now the hum and electrical interference is no longer a problem.
Maybe this microphone could be interesting for other members who are looking for something similar.

 

[rock soderstrom]

Interesting.

- Affordable (Requirement number one!)

339€ on this site:

http://www.recording-tools.com/prod...on-mit-umschaltbaren-richtcharakteristik.html
RecordingTools.com is a german company, I guess this mic is produced in China. It is possible that we can order it directly there for smaller € if we find the source.

 

[RuudNL]

Yes, it looks like a Chinese product.
But even for €339 (as a company I don't have to pay the VAT or MwSt) it is an interesting product.

 

[ubxf]

It looks interesting, i found this one but it is double the price and probably the same
http://recordinghacks.com/microphones/Avant/CK-40http://recordinghacks.com/microphones/Studio-Projects/LSD2

 

[mrgrooves666]

I have spotted this same mic in reverb and always dabbled with the same idea of getting one. Thanks for sharing!

 

[kingkorg]

Wow Ruud, you are killing it as usual!

The first thing that comes to mind is to make it quad output. And use with something like Austrian Audio polar designer.

 

[RuudNL]

@ubxf: It looks indeed very much like the Avantone.
The only difference seems that the Avantone can rotate the upper capsule 270 degrees, while the Recording Tools can only rotate 90 degrees. The Recording Tools MCS-02 also has a trimmer potentiometer for the FET bias, that wasn't set at the optimal position for max. SPL and/or lowest distortion.

 

[k brown]

I think the first mod I'd try to make would be replacing the pattern switch with a four-position, so one could get hypercardioid; extremely useful pattern.

 

[Papa Tango Charly]

It's funny, i'have looked at those mic. the C12 capsule are very nice i have bought 2 C12 capsues they are really good sounding. This guy B. Loffet, peace to his soul, have made beautiful microphone out these microphone body. Micro statique à tube à large membrane B. Loffet BL-6
Photos et images B. Loffet BL-6 (3/10) - Audiofanzine. best

 

[Papa Tango Charly]

https://fr.audiofanzine.com/micro-statique-a-tube-a-large-membrane/b-loffet/bl-2/

 

[kingkorg]

By the way, here's the manufacturer

https://www.aymaudio.com/product/stereo-diaphragm-condenser-microphone-scm-2/

 

[ccaudle]

(Is there even a standard for stereo microphones?)

AES14-1992, r1998, "Application of connectors, part 1, XLR-type polarity and gender"

pin 1: screen
pin 2: left channel positive polarity
pin 3: left channel return
pin 4: right channel positive polarity
pin 5: right channel return

I suppose mapping L and R is left to the user if using in a non-stereo configuration such as M/S.

 

[Icantthinkofaname]

By the way, here's the manufacturer

https://www.aymaudio.com/product/stereo-diaphragm-condenser-microphone-scm-2/

Is this the actual manufacturer? I aso because they have a small diaphragm condenser that looks exactly like the iSK CM-20 series, but renamed MC-20. They claim 15 dBA self noise compared to 20 dBA on iSK's. Everything else seems the same. They also have what appears to be the iSK CM-10 (Little Gem), with the same specs including self noise of 24 dBA.

 

[kingkorg]

Not sure, seems like it. However i wouldn't pay attention to the specs, they seem pretty random.

 

[RuudNL]

By the way, here's the manufacturer

https://www.aymaudio.com/product/stereo-diaphragm-condenser-microphone-scm-2/

From now on we will call you the "Microphone Sherlock Holmes".

 

[kingkorg]

 

[dandeurloo]

For years I have been planning to build a stereo microphone with a rotatable microphone capsule.
The main reason I never realized this were the mechanical difficulties in doing this properly.
By coincidence I found a microphone that already meets most of my requirements:

- Affordable (Requirement number one!)
- Two double sided edge terminated microphone capsules
- Separate pattern selection per microphone system (Omni, figure-8, cardioid)
- 10 dB pad + low cut filter per microphone system
- Top capsule rotatable from 0 to 90 degrees

This microphone could be used for X-Y, M-S and Blumlein recordings.
The microphone uses a modified Schoeps circuit and a DC converter for the polarisation voltage.
Although I thought about modifying, the quality is adequate for my needs.
There are a few things that I have changed:
- The capsule polarisation voltage was about 40 volts, I have raised that to 50 volts.
- The wiring of the 5-pin XLR connector was a bit strange. (Is there even a standard for stereo microphones?)
The original connection was: Pin 1+2 microphone 1, pin 3 shield/'ground', pin 4+5 microphone 2.
Since another stereo microphone that I own has a different connection, I have changed this to: Pin 1 shield/'ground', pin 2+3 microphone 1, pin 4+5 microphone 2.
The only obvious improvement are the headbaskets.
These headbaskets are single layer mesh, but do not provide enough shielding for electrical fields.
I have added a second layer of mesh and now the hum and electrical interference is no longer a problem.
Maybe this microphone could be interesting for other members who are looking for something similar.

View attachment 92313

Any idea how to get the headbaskets apart on these? I have a Avantone CK-40 that has a loose capsule in the top. I can't figure out how to get the thing apart to fix or replace the capsules.

Any one ever get one apart before?

Thanks

 

[Migs 31]

Big thanks to @RuudNL for sharing info on this mic/body. Inspiration.

I wonder, will the heat dissipation of a 6072-12AY7 be too much in this?

M

 

[Migs 31]

Any idea how to get the headbaskets apart on these? I have a Avantone CK-40 that has a loose capsule in the top.

Hi there @dandeurloo
Mine seems to have three small Star shaped screws between Top & Bottom head basket. Could it be that you have to undo those, to make the top head basket accessible ?!?

I’m working on a 6072 based prototype on this. Sounds very promising.

M