Brian Roth
Well-known member
I ASSume the tape heads are properly demagnetized since that can cause what sounds like "bias rocks". Dunno about the hum problem.
Bri
Bri
I find steel plate is helpful for hum shielding. If you can get your hands on a piece of steel and insert it between the underside of the motor and the top of the electronics cage, you should be able to either prove or reject this theory in short order. I have used things like steel rack panels, steel lids off of electrical back boxes, the steel angel brackets that you get at building supply stores to aid in wood-frame construction and angle-iron. Typically, thicker steel will have more effect than thinner steel, but the quality of the steel makes a difference too. The plate does not need to be grounded to have a shielding effect. It occurs to me that a steel mixing bowl might go around the bottom of the motor, but I'm way more familiar with the MM-1200, and haven't even seen one of those in aeons...so no idea if that would fit.Yes the hum is most prominent on channels 3,4,7,8,11,12,15,16 which are on the right side of the machine under the take up reel. The other channels have a marginal amount of hum. I'm not sure if it has something to do with the power supply transformers when the reels are under load. Not sure if it is inducing some kind of hum into those tracks closest.
Enter your email address to join: