My Cary PH 302 phono amp MM hum?


My Cary tubed PH 302 phono amp sounds great running an Ortofon Rondo Blue through the Moving Coil section but it has developed a hum with my Shure V15 III in the MM input. I have experimented with all the usual suspects that can be related to ground loop feedback. So far nothing has worked. The tubes test perfect. I have the same hum with a variety of cartridges and turntables. Has anyone had this problem with this phono stage? Thanks.
Sharpe
sharpe

Showing 4 responses by alan2

Hello Tobes, I have the original PH-302 and I wanted to ask your advice on changing the tubes. I see that you're using Sylvania 1968 era. What do you think of Sylvania 1944 army military VT-229/6SL7 GT?
Hi Mechans, The tube are $80.00 plus tax and shipping. I need four $375.00. What do you think?
Hi, Thanks for getting back to me regarding the tubes. I have not purchased them yet. I would need four and they're $80.00 each.
GE GSL7/5691
ADZAM GSL7GT

I can get both matched. But not sure which one to get?