Scott, Harvey -

A question about the Oktava ML-52 Ribbon mic. I just took the
windscreen off the base of the mic to have a look under the hood.
There are two vertical ribbons pretty well hidden inside the magnet
structure. Mounted to the surface of the magnets is a metal plate with
a series of 7 vertical holes in front of each ribbon.

Now the interesting part...suspended in front of the holes in the
metal plate is a brass fixture shaped like a goal post - the two
uprights block direct access to the holes in the plate in front of the
ribbons.

Question, what's the purpose of the brass plate. Some sort of HF
tuning?

On another note (literally), the windscreen seems to be made of the
same ringing cast alloy that makes the MK-219 boink before it is
damped in some way. I'm thinking of cutting out the radiator grilles
and replacing them with another layer of wire mesh. But first, inside
the windscreen, next to the wire mesh screen, is a layer of very fine
weave textile. It doesn't look too open to my eye and I wonder about
its HF transparency. I'm wondering if I can just pull this stuff out
and use an external popper stopper instead.

Where I'm going with all this is...the frequency response graph of
this mic shows -1dB at 1.5kHz, +1dB at 3kHz, a narrow -5dB notch at
5kHz returning to -3dB from 6-9kHz, then +3 at 12kHz followed by a
rapid cut-off. I'm wondering if the holes and brass plate is an
attempt to boost the HF but introduces response bobbles and phase
problems in the 5-9kHz region.

If this is indeed a mechanical top boost, I'll pull the sucker out and
hopefully straighten out the response curve. There's too much 12k in
the world anyway.

The transformer investigation will have to wait for another day.

MJ