Ampex 350 steady Popping - hissy - crackly noise

[jwhmca]

It passes audio at least with a mic as input. Any common issues?

I have it recorded, can I post it someplace?

 

[emrr]

I'd call it a noisy carbon resistor.....after I cleaned every contact including the tube sockets, subbed out the tubes with known good tubes, isolated the stage the noise is coming from, etc etc. 

 

[jwhmca]

It doesn't change loudness with either input or output gain. If i turn the mic all the way down it's still there?

I'd call it a noisy carbon resistor.....after I cleaned every contact including the tube sockets, subbed out the tubes with known good tubes, isolated the stage the noise is coming from, etc etc. 

Are you saying a carbon resistor has gone bad in some way and is making this noise?

 

[mjrippe]

Unfortunately lots of things can make noise in old tube circuits and a lot of them sound similar.  Capacitors, resistors, tubes, damn near every part that can be replaced!  Follow EMRR's advice to narrow it down.  If you have the input gain down, it is more likely to be a power supply issue or something in the output stage.