Technics SU-V9 ingrated amplifier - phonostage - questions
Dont want to bore with the long story, basically the amp had to recapped, and also ICs replaced due to slip of probe and a few bad caps.
She was working perfectly, this one day on fire up high pitch sound much worse on phono, with the decouping caps removed, no more issues. Either the OPA1642 was oscillating or a faulty part - lucky I was, a board come up and i have a new used board.
Installed LME49860 soic - dip adapter, electros on the phono are Pano FR and Nichicon PW( image 2 C123/124 47uf25v) near IC. Another thing, there isnt cross talk which was much worse before the new board.
Kept the old crusty phono cable this time inside the amp? was thinking of replacing it also, but maybe will cause problems.
Currently decouping cap is a Wima FKP, was thinking of using a standard Auricap?
Changed resistors in signal path ( 2 of them yellow on image 2 R 144/143) to Vishay Dale RN65e
Wima cap? or Nichicon ES or Auricap? ( C118/117 red image 2)
Wonder if caps are best kept or removed filter ones C119/120 0.0047uf (gold cross image 2)
thanks Sam :)
image phonostage schematic
http://i64.tinypic.com/5d56jn.jpg
image 2 close up IC
http://i65.tinypic.com/2gwb382.jpg
On my Technics su-v8 i used digikey tensility spiral cable
She was working perfectly, this one day on fire up high pitch sound much worse on phono, with the decouping caps removed, no more issues. Either the OPA1642 was oscillating or a faulty part - lucky I was, a board come up and i have a new used board.
Installed LME49860 soic - dip adapter, electros on the phono are Pano FR and Nichicon PW( image 2 C123/124 47uf25v) near IC. Another thing, there isnt cross talk which was much worse before the new board.
Kept the old crusty phono cable this time inside the amp? was thinking of replacing it also, but maybe will cause problems.
Currently decouping cap is a Wima FKP, was thinking of using a standard Auricap?
Changed resistors in signal path ( 2 of them yellow on image 2 R 144/143) to Vishay Dale RN65e
Wima cap? or Nichicon ES or Auricap? ( C118/117 red image 2)
Wonder if caps are best kept or removed filter ones C119/120 0.0047uf (gold cross image 2)
thanks Sam :)
image phonostage schematic
http://i64.tinypic.com/5d56jn.jpg
image 2 close up IC
http://i65.tinypic.com/2gwb382.jpg
On my Technics su-v8 i used digikey tensility spiral cable
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