huge BUUUUUUUUUUZZZZZZZZZ problem

[antispatula]

So I still don't know what I'm talking about when it comes to reel to reels, or equipment, and am still pretty new to all this.

So I got a mixer, then had to return it, and now finally have another one. I tried my mono recorder today, I wanted to see how it sounded through a mixer. So here's the problem:

The first time I tried it, a few months ago, it worked great it seemed. Now when I reocrd onto it, there's a terrible buzz. Anyone know what that can be? I know the tape is basically crap, and the reel to reel says it's also a preamplifier...... And I'm running all this through a mixer.....Any ideas? Thank!

EDIT: So I just tried it again, a few minutes later. Turns out it's working ok again......I remember someone once said it had to do with......wait......I don't remember at all. Anyways, so it seems like if I keep it on for more than a few minutes, it starts to suck, is there any explanation and way to fix this?

 

[arjoll]

EDIT: So I just tried it again, a few minutes later. Turns out it's working ok again......I remember someone once said it had to do with......wait......I don't remember at all. Anyways, so it seems like if I keep it on for more than a few minutes, it starts to suck, is there any explanation and way to fix this?

Some possibilities - RF leakage (do you have any amateur radio operators nearby? also try turning off your cellphone), maybe a dead/dying cap (check decoupling caps in the record section). An earth/ground loop is a possibility but these usually aren't intermittent. Also try turning off any lights that have dimmers.

 

[evm1024]

If a filament touches the cathode you will pick up a 60/50 cycle hum. An old trick from my tube days was to tap each of the tubes with the handle of a screwdriver to see if it was audable through the speakers.
Any tube in which the elements were so loose as to pick this us has an internal fault. They were "harmonic".

Not saying that this is your problem....