Who knows the intercom below (or have the manufacturers telephone number?) I have a coupe of queries???

I got this intercom with the purchase of my plane 2nd hand, no manufacturers markings.
I need to know what the 2 little BLACK Variable Resistors adjust.
My Transmitting Radio Comms through the intercom is crystal Clear but very Soft to other Pilots listening in on the radio 5 & 3 out 5 respectively. The Reception is perfect on my side.
If I bypass the intercom and use the Icom IC-A3 Radio's built-in Speaker/Mic (i.e press and speak into the handheld) the Volume is much better for receiving pilots 5 & 5 out 5.
Hence I guess the output "GAIN" needs to be adjusted on the intercom.
Any ideas and help appreciated.
Failing that, I might be in the market for a NEW intercom!
Something with Audio Out and Audio In, so I can listen to my IPOD, and Record our Radio Comms on the video camera. What is available and GOOD on the TRIKE market nowadays that you guys can recommend?
Kind Regards
Rudi