oops Chris, your last posting was 'empty', quotes only
just got a reply from the 'boss',
I don't think a transformer is going to be a solution. The best place
to use a transformer is between the microphone and the pre amp. This
way you get gain without increase in noise. Unfortunately this circuit has a low input impedance around 600 ohms.
The article states that you could use a 1:1 transformer but this will not help the gain. I would have
recommended our type 4935 but this has to feed a high impedance e.g.30 K ohms. It will not work
feeding into a 600 ohm load.
I am sure there are other pre amps you could make which could be used
with 4935
aarrgh...