U47 noise question



I have a U47 now that is suffering from a bit of very low freq hiss. Also, I find it has a relatively low output. (At least compared to a C12 that we`re using on the same project. I can't compare it to another 47.)

Now the tech person at the studio has replaced all the caps in the mic and power supply. Also the tube socket has been cleaned. The only part that has not been checked so far is a 110 ohms ceramic resistor in the mic that I've been told could be problematic. We checked two different tubes and the noise problem is similar. The capsule is totally mint looking. Has anybody had similar experiences with one of those? There are not a lot of tech persons experienced with U47's around here, so any useful info would be appreciated!

Eric Filteau
Ground Control Studio
Montreal, Canada.


It's hissing at you, cause it doesn't like all you people sticking your fingers in it... :eek:


I have a (older) U87 that seems to be having low output also, and at time the U87 will actually breakup, as if there is an internal short (xlr? faulty capacitor?).

I'm no tech, but I have heard reports of Neumans being finicky & needing to be reworked.