I have heard there is a simple modification, an adjustment really, to
earlier Meumann U-87s. Those from the seventies and eighties had a lower
output, and apparently, one can set or solder a jumper on the
transformer to increase the output by 6 db. Wonder if anyone knows how
to do this.

Thanks,

CA

Hmm, not really.

If you have a U87p, it means there's an output pad.
Just bridge R20 and R21.

Of course, "regular" U87s could be padded at any point in time too, so you
want to make sure that those two Rs are bridged (not in circuit).

Then look at the transformer wiring: everything is clearly labelled, it
should be wired for 200 Ohm, which means one central link, not two =
secondaries wired in SERIES.

If your mic is unpadded and set to 200 Ohms and you really want to add more
output, you need to replace the battery holder with a DC/C converter to send
60VDC instead of the original +/-47VDC to the capsule, effectively turning
your U87 nto a U87A. You lose 5 dBs of headroom doing this, but the noise
floor drops a bit.
German Masterworks will do this.

Check that the capsule is OK, a typical sign of capsule aging is loss of
sensitivity (obvious is the gold plating on the diaphragm is gone or just
looking worn/transparent).

Finally, you could have a bad FET. **** happen...

So start by checking the transfo wiring and whether the pad is active or
not.

JP

"Charles Adams" a écrit dans le message de
...
I have heard there is a simple modification, an adjustment really, to
earlier Meumann U-87s. Those from the seventies and eighties had a lower
output, and apparently, one can set or solder a jumper on the
transformer to increase the output by 6 db. Wonder if anyone knows how
to do this.

Thanks,

CA

Charles Adams wrote:
I have heard there is a simple modification, an adjustment really, to
earlier Meumann U-87s. Those from the seventies and eighties had a lower
output, and apparently, one can set or solder a jumper on the
transformer to increase the output by 6 db. Wonder if anyone knows how
to do this.

I think you're talking about the output transformer strapping. The details
are in the manual that came with the mike. Set the strapping for whatever
the input impedance of the preamplifier you are using is.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."