slimecity
Super Member
Hi all -
Kevzep and I have gone thru my X1 and I have a nagging issue in the flat amp board. Kev replaced pretty much all the transistors in there, and I replaced all the zeners. That only left the caps - which I fully re-did tonite.
The only original semiconductors in there are the two UPA68H. Tonite I was testing it and I was sure I heard the dreaded "crack bang pop" again - this is what I have been chasing. Its always in the right channel and goes away totally when pressing the jump switch (bypassing the flat amp). Its worse in the cold - ie: with cold starts.
Questions:
There are mixed views on using freeze spray on fets - can I do it safely on these fets - given that I am not going into the poweramp section (I am running a feed out of the preamp out RCA's to my 555a). The amp is switched to seperate when I do this.
I have some spare UPA68H - two pairs. The first pictured ones came from UTSource (same size as the fitted ones), the second from LittleDiode (I think, these are smaller, a slightly different type - it was a supposedly more reputable supplier but I got these a while ago).
Do any of these look genuine? I dont have a curve tracer. Does anyone have a source for these they completely recommend getting good parts from?
Cheers!
Kevzep and I have gone thru my X1 and I have a nagging issue in the flat amp board. Kev replaced pretty much all the transistors in there, and I replaced all the zeners. That only left the caps - which I fully re-did tonite.
The only original semiconductors in there are the two UPA68H. Tonite I was testing it and I was sure I heard the dreaded "crack bang pop" again - this is what I have been chasing. Its always in the right channel and goes away totally when pressing the jump switch (bypassing the flat amp). Its worse in the cold - ie: with cold starts.
Questions:
There are mixed views on using freeze spray on fets - can I do it safely on these fets - given that I am not going into the poweramp section (I am running a feed out of the preamp out RCA's to my 555a). The amp is switched to seperate when I do this.
I have some spare UPA68H - two pairs. The first pictured ones came from UTSource (same size as the fitted ones), the second from LittleDiode (I think, these are smaller, a slightly different type - it was a supposedly more reputable supplier but I got these a while ago).
Do any of these look genuine? I dont have a curve tracer. Does anyone have a source for these they completely recommend getting good parts from?
Cheers!