I had an old MMII preamp. This was a mic preamp designed by Joe D’Appolito. It had 6dB of gain, but more importantly, had the correct bias voltage for the standard panasonic mic capsules. It died on me a while back. It didn’t matter when I switched to praxis, since praxis has the correct bias voltage.
The problem is that I’m curious about some of the other software out there, like ARTA. I’m trying to set up a new, portable measurement system. The problem is that most sound cards have no bias voltage, or the higher pro level voltage. You can buy one, but I’ve already got an m audio transit, which is a fine card for measurements (48k sampling). So I needed a working preamp. I pulled the MMII and it just turned out to be some loose wires where the 9v battery was soldered to the board. (Uh, it was me that originally soldered it.)
Below you’ll see the transfer function. This is about as flat as you get. You’d have to obsess about parasitic reactance in the cables to get much better.
Why should you care? Hopefully in the next couple of months I’ll have a review of ARTA. I can also get an SE measurement system up and running.