[TenTec] Using a Yamaha CM500 headset with TT Orion II - advice needed!

[Steve Ireland]

G’day

I have been trying to use a Yamaha CM500 headset with my TT Orion II and have been having a few issues in getting levels right in the Orion with the electret mic.  Please, if anyone is using a similar set-up and are happy with the results, I’d really like to know:
  a.. what is used in the way of a resistor/pad between the 10V output from the TT Orion mic socket and the 3V CM500 electret bias? 
  b.. what is used (if any) in the way of a pad to reduce the output of the electret mic?  
  c.. what setting is used on the MIC gain (i.e. the DSP mic gain, set using the MIC button and the MULTI pot)? 
  d.. what dB setting is used on the H/W mic gain (i.e. the hardware mic gain, set using SSB menu function)?
At present I am using two 2.2K in series as a voltage divider to reduce the 10V bias to around half (i.e. 5V), and then reducing the electret mic output by a voltage divider using a 430 ohm resistor in series with a 220 ohm resistor and taking the output from the top of the 220 ohm. I also have a 4.7uF electrolytic in series with the electret mic output voltage divider so as to block any DC potential (to be sure, to be sure) coming from the electric mic element back into the TT Orion mic audio input.

My current set-up isn’t working (sounding) well and the best thing seemed to be to ask for some advice.

Vy 73

Steve, VK6VZ   

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