SSMH - fried Mosfet?

Hi all, quick question:

I just finished my SSMH build (p2p), and everything sounds great in the left channel (the bass is incredible!), but the right channel has no sound and the heat sink on that side is getting darn hot. From what I read, this sounds like I fried the mosfet and it's shorting, but I'm new to all this and wanted to confirm. Could it be something else?

Thanks!

This is what I get for working at 2am. The dysfunctional side is not the one that is heating up. On second look, "darn hot" is not even 60C, but I haven't left it running long enough to see if it'll get hotter. The side that has no sound stays cold.

These are the voltages at the mosfet pins:

left channel (working):

G: 16

D: 48

S: 13

right channel (not working):

G: 48

D: ~2

S: ~2

This is the version that uses 12SR7 tubes.

Quote:

Originally Posted by nikongod 

Something is very wrong with that.

And that something is me. Desoldered, checked everything, turned out I had soldered pin 1 and 2 wires backwards. The voltages are correct now, and I even get sound out of that channel, but it is barely audible. I didn't think to order extra mosfets, so I don't have another on hand to swap in, otherwise this is what I'd do next. I'm going to check for a bad contact or wrong resistor somewhere in the circuit, but does the fact that there is sound indicate the mosfet is fine? I know that miswiring is likely to fry it, but in that case shouldn't I expect no sound at all?

All fixed, it was a grounding issue at the input. Miraculously, the mosfet appears to have survived just fine. Thanks for your help, guys :)

Now, for some listening ;)