parasound hca-1500a distortion on right channel.

[rayma]

If he can't help you, I don't know who else could.

 

[mlloyd1]

these mosfets are not interchangeable; they are different technology mosfets.
for starters, the biasing for the 2sk1058/2sj162 is different from 2sk1529/2sj200.

Hi rayma ,in the schematics the drivers q116 =j162 ,q111=k1058, in my specific amp ive found j200 q=116 ,k1529=q111, on both channels .
They interchangble?
Ive found new 2 pairs of j162 &k1058 renesas in my spare parts...

 

[eldad]

Hi friends a update ,i replaced the drivers j200 and k1529 in the bad channel reset the bias both channels ,problem solved.
Also changed the bias pots to bourns sealed multi turn.
Im adding spectrum pics.
Thanks you again friends.
E.g after some mods the amp sounds great.
(Feedback and input resisors non magnetic,all cable end terminals screws are non magntic brass including binding posts ,check and rewire main input ac phase for lowest leakage .)

 

[rayma]

Good work, and those magnetic parts were Parasound's idea, not JC's.