Hi guys, I've got a slight issue when I first turn on the amp on. This happens with different tubes and tubes swapped from left to right as well. I have a very loud hiss at no volume in only the left channel. It doesn't change with volume or with input disconnected. I've exchanged quite a few emails with Tomb on this and just trying to see some others thoughts as well. The odd thing is, after the amps warmed up a bit the hiss is gone, or at least inaudible to my ears. This morning got it to disappear just by turning the volume pot up to about half volume. At that point the hiss ramped up louder (almost like a crashing wave or inrush of current) and then goes away completely. Once it's gone, I can completely turn the volume all the way back down and it's dead silent. I thought perhaps I overheated the front z switch desoldering it to get it to properly line up with the front panel (since only after I moved it and re-soldered it did I get the noise), so I removed the z switch altogether and added jumpers. That seemed to cure the problem at first attempt. But in the morning here at work the hiss was back. I should also add I trimmed the pot shaft (to get knob closer to amp) with my dremel at the same time I moved the switch. I've ordered new zeners, new switch and all new rectifiers, new led's, transistors and more from mouser just to have on hand to try and get rid of this. Probably be here by this weekend so I can do some troubleshooting. Any ideas gents? Also The amp sounds absolutely fantastic warmed up and with no hiss. I can listen all day and the hiss never returns.
Edited by tdubl07 - 3/19/14 at 8:54am