Cisco audio Science ceiling Mic and SX20

[RobPendleton]

  Hi Folks

We have a customer that has purchased a SX20 and also a Audio Science Ceiling Mic. I had a 3.5 "4 Pin Cable" made up to extend from the Codec, But when I plug in the Audio Science ceiling Mic , I cannot be heard.

Has anyone com across this issue ?

I have checked the pin outs ...all ok.

As a thought ...Are they compatible ?

Thanks

Rob                

[t.svatek]

Hi Rob

Maybe the following could work - I haven´t tested this, but maybe you could:

notes:

• use resistors with a very low tolerance like 0,04% or lower!
• maybe add a capacitor within both Audio lines to block DC from SX20
• check, if 11V are enough for your mic
• it should work for any symmetric condenser mic with xlr
• it will not work for electret mics, like those very cheap asymmetric PC-Mics with a 3,5mm plug
• no warranty

The disadvantage will be, that you´re not able to control the volume and that you will make the cable by your own. There may be better ways to solve this:

• Good: Use an external Phantom Power Supply
• Better: Use an external Mini-Microphone-Preamp to get Phantom Power and sound level
• Best: Use a C40 instead, like Martin said ;-)

Thanks

Tino

[Darren McKinnon]

We used the schematic above, inserted 2 capacitors, and verified this works great!  My users are very happy.  Below you will see our notes/comments.  We really needed this to work, so I cut the phono plug off of the supplied SX20 microphone to make this cable.

[t.svatek]

good to hear. thanks for testing.

I´ve summarized all

http://conftech.blogspot.co.at/2013/06/connect-third-party-microphone-to-cisco.html

[Darren McKinnon]

I had to make several more of these connectors, so I sourced the 4-conductor, 3.5mm plug from digikey: PN- CP-354S-ND.  Only $7.30 ea.

[Wayne DeNardi]

There's lots of places you can get them, and $7.30 is pretty expensive.  You can get just the 4 pole 3.5mm jack for US$2.35 from Element14: PSG01490

Wayne
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[t.svatek]

If you prefer to get it ready made, you could also use the revolabs cable together with two adapters:

Vendor	Part #	description
Revolabs	07-35MBTO35M4-01	3.5mm Balanced Male Connector to 3.5mm Male 4 Conductor
Neutrik	NA3FJ	Neutrik NA3FJ Stereo Jack to XLR-female
Hosa	MHE-310	Stereo Mini Female to Stereo 1/4" Male

You can get it from www.bhphotovideo.com or other sources.

The last two adapters can be replaced by other brands if needed.

I have also found a ready-made one here, but it seems, that it has a XLR-male instead of a XLR-female - i have send a message to them regarding this.

In anyway, you´ll need an external Phantom Power supply, if the Mic needs power.

[t.svatek]

The guys from AVShop.ca confirmed, that their ready-made microphone cable for SX20 comes with a XLR-female instead of the XLR-male like shown on the photo.

They also confirmed, that they can ship the cable globally and they do also have a suitable phantom power supply if needed.

You can order it here.

thanks

Tino