B&K 2603 for Altec M-11?

I'm trying to wrap my head around what's needed to convert this measurement mic pre/psu to work with an Altec M-11 mic. Anybody ever done anything with one of these?

Work involves step-up transformer to the input, and output transformer after cathode-follower at the out

I never got it to work well..

Circuit is optimized for frequency response NOT for noise (as we don't care beyond the -20dB tha tcan be shown on meter scale)

Jakob E.

gyraf said:

Work involves step-up transformer to the input, and output transformer after cathode-follower at the out

Click to expand...

I think for the M-11 you can skip the input transformer.  The mic sends signal straight off the cathode of the 6AU6 and there is an output transformer in the PSU.

gyraf said:

Work involves step-up transformer to the input, and output transformer after cathode-follower at the out

I never got it to work well..

Circuit is optimized for frequency response NOT for noise (as we don't care beyond the -20dB tha tcan be shown on meter scale)

Jakob E.

Click to expand...

What do you think is the reason for noise as built? Layout? I was hoping to use this thing as the mic psu and preamp in one box. I will attempt to draw a schematic of what I've attempted so far, I had no signal from mic at that point.

Dmichel123 said:

What do you think is the reason for noise as built?

Click to expand...

The circuit is optimized for linearity, not noise - because whatever err-readings you have below -20 on the meter scale is wholly insignificant in real use.

Let me know what you come up with - I still have the unfinished project stashed somewhere..

After some simple modification, it is a very good microphone preamplifier, at the end of the noise is very low, if the amplifier input, increase a 1:5 step-up transformer, the output increase a 1:1 or 2:1 output transformer, power supply part have to do a simple isolation, otherwise there will be a current sound, tone is very warm, the noise is very small,Can be suitable for any microphone.