How can the TRV900 audio performance be improved?
[7/24/2004] Initially, there was no known solution. More recently the answer is yes, the TRV900’s audio performance can be significantly improved by a modification that bypasses its internal mic preamp. Damir Vrancic modified his camera as described here. He just bypassed the first two gain stages (BA7780 and M5222 chips) after the external mic input, with the effect that gain is fixed (roughly mid-range) but he got 14 dB better noise and better frequency response, relative to the same gain in manual mode. He mentions he could have got about 3 dB lower noise if he’d omitted a 1k series resistor after the mic input, but I agree the 1k is a wise precaution against possible overload damage. Greg Winter also did a modification, which he measured to have 13 dB lower noise, 13 dB higher SNR, and better frequency response. You can see the difference here: TRV900 Comparison. You can contact Greg Winter to ask about doing this modification on your camera.
