Add group to favorites
Back to post list
Send new message to group Search:
Post Subject:
Jolida 502 OK with 1650P Hammond OPT.
Jolida 502 OK with 1650P Hammond OPT.
I've just finished installing a pair of replacement Hammond OPT
into a Jolida 502 amp and have Svetlana winged C 6550 outputs.
Aahhh, music. I had been testing an old Akai and an old Sonab all week
to
to make sure they were OK after their repairs, but of course the tubes
were refreshing to return to.
I mentioned in my other posts about what i did to lower noise.
I eventually settled for a 2H plus 235uF B+ filter on the B+,
and having all the drive amp ac heaters biased at +65Vdc, and
with quasi CT, to give a balanced 3.15V-0-3.15V applied to all heaters.
No noise can be heard from the amp even with an ear against the speaker.
Its now one of the quietest amps I have ever modified.
I usually us dc for heaters, but I didn't in this case, and got really
excellent results.
Patrick Turner.
I've just finished installing a pair of replacement Hammond OPT
into a Jolida 502 amp and have Svetlana winged C 6550 outputs.
Aahhh, music. I had been testing an old Akai and an old Sonab all week
to
to make sure they were OK after their repairs, but of course the tubes
were refreshing to return to.
I mentioned in my other posts about what i did to lower noise.
I eventually settled for a 2H plus 235uF B+ filter on the B+,
and having all the drive amp ac heaters biased at +65Vdc, and
with quasi CT, to give a balanced 3.15V-0-3.15V applied to all heaters.
No noise can be heard from the amp even with an ear against the speaker.
Its now one of the quietest amps I have ever modified.
I usually us dc for heaters, but I didn't in this case, and got really
excellent results.
Patrick Turner.
