I'm loving this amp in unbalanced mode to my HD650s. Next is to make a balanced headphone cable.  
Goals: 
— Not too bulky for portable use (no XLRs)
— But adapable to desktop amps (adapt to XLRs later). 
... hence, I'm considering using an connector such as mini-XLR to a short adapter from mini-XLR to RSA Kobiconn connector.  
 
Here is my long-form set of notes: 
 
 
 
BALANCED CABLE ADVICE? 
 
I would like to build balanced headphone cables, primarily for RSA portable use... so hoping to avoid bulky full-sized XLRs that otherwise might be further adapted to a short RSA cable. Instead, I might add a mini XLR adapter to make it flexible for use on other amps?  In other words....
 
For balanced, I first thought I could ask Cardas to build it, and terminate with a male version of the "RSA" version of the Kobiconn connector.
But that makes it a single-amp cable, because I cannot find a female on-cable version of the Kobiconn. 
 
So, I either accept it as a single-amp cable, or I insert a small adapter. My preference is the mini XLR.  
 
Here are my ideas: Terminate with a mini XLR male on the headphone cable, and then use multiple adapters, one to RSA male, and for desktop amps, I could adapt to XLR male (a single 4-pin, or two 3-pins).

Main "universal" cable:
HD650 -- Cardas Clear Light -- mini 4pin XLR male

Adapters:
Mini 4pin XLR Female -- RSA 4 pin male (for the RSA SR-71B Blackbird... use it almost all the time)
Mini 4pin XLR Female -- two male XLR 3 pin (full sized) For future home amp
Mini 4pin XLR Female -- single male XLR 4 pin (full sized) For future home amp

Any comments, or pin diagrams, would help. I have trouble identifying on male and female which pin is "1" and whether numbering goes clockwise or CCW. 
 

Here is what I've found so far about the male connector that would connect into the RSA amp: 
 

 
 

About the on-cable plug for Ray Samuels Audio (RSA) portable balanced amplifiers:

1. The novel aspect of RSA amps is the innovative use of a particular connector to provide a balanced interface of small size.
2. The connector is normally used for cameras but has been shown to work very well for this purpose. 
3. Ray sells quite a few of these amps.  The amp I am using is relatively new and top-of-the-line, very powerful.

Plug Dimensions:

Attached is a PDF with full dimensions, excerpted below.
Judging from this drawing, the opening for the cable is 4mm.  The Cardas team was able to terminate it with Clear (2 Clear Light cables).  
 

 
 

 
 
 
 
Pin Definitions:

From Ray Samuels (rsaudio@raysamuelsaudio.com)

Left Channel:
  PIN # 1 is POSITIVE
  PIN # 3 is NEGATIVE
Right Channel:
  PIN # 2 is POSITIVE
  PIN # 4 is NEGATIVE

Pin definition for the socket in the amp. Reverse this to view from outside.
 
 
 
 

 
 
 
 
Pin definition for the plug.  Viewed "through" the back of the plug.
 
 
 
 
 
 
 

 

Physical Orientation:

The pin definitions is consistent with the physical orientation below, which avoids interference with the volume knob. See picture:
 
 

 
 
 
 
 
 
Supplier:

Mouser #: 163-191J-E
Mfr. #:    163-191J-E
Desc.:    Phone Connectors CAMERA PLUG 2PC cable size 2-4

http://www.mouser.com/ProductDetail/Kobiconn/163-191J-E/?qs=C8m%252bmemFVBP34xgvdBuhwA==

http://www.mouser.com/catalogviewer.aspx?page=1389&highlight=163-191J-E&catalogculture=en-US&catalog=646
 

Someone just told me about this thread and it is just what I'm looking for.
So you guys are after the male plug and do you know it is possible to buy the female panel plug ?
I want to divert the speaker taps cables to the front for this type of connection. My guy can mod it on to the front panel I think...
 
EDIT : it was sent to me already from another member.

Hey can you tell me the size of the heat shrink that you use ?

Hi, I made just this: a tiny-XLR to RSA adapter. However, I now get mono sound. What might I have done wrong?
 
Thanks, Daan
 
EDIT got it.

What did you do wrong ? I'm making one soon.

lohb said:

  What did you do wrong ? I'm making one soon.

Click to expand...

I believe the numbered schematic above is wrong. Here is what worked for me. Viewed from on top of the plug, the soldering side.

I had this....same-same from female port side.

Great, I even had the polarity right!

Are you running your RSA to Fostex ?
How does it sound ?  I'm hoping balanced re-cable will take it up a level...

daanh said:

  I believe the numbered schematic above is wrong. Here is what worked for me. Viewed from on top of the plug, the soldering side.

Click to expand...

Very useful thread, thanks. I'm working on balanced cables for the Centrance GloveAudio A1 which is the same pinout. I agree with the diagram above which also matches the Wiki here (see row entitled auto-IRIS).

daanh said:

  I believe the numbered schematic above is wrong. Here is what worked for me. Viewed from on top of the plug, the soldering side.

Click to expand...

 
When working with Shure MMCX connectors the +ve connector is the pin (signal) and the -ve connector is the shell (ground).

I just purchased a SR-71B and this thread really helps for going balanced. Thanks everybody for all the great information above.

Hi all, I just completed a RSA to 3,5mm jack adapter cable. Handy for when the battery of my Intruder dies while on the road. I got the female RSA from Ray, but it was difficult.
 
Daan
 
EDIT: it was a nice idea, but the RSA female plug is just too vulnerable. After applying tape to provide pull-relief and re-soldering the thing like 10 times, I gave up.