Not sure if this is what you're asking about but if it is, our very own Ronito has you covered.
http://audiokarma.org/forums/index.php?threads/rare-reed-relay-substitution-a-visual-how-to.771050/
Sansui AU-919 restoration/upgrade thread
- Thread starter mattsd
- Start date
-
- Tags
- au-919 recap restoration sansui
Not sure if this is what you're asking about but if it is, our very own Ronito has you covered.
http://audiokarma.org/forums/index.php?threads/rare-reed-relay-substitution-a-visual-how-to.771050/
kevzep
Its all about the Music
Thats it!! Perfect, I have a few of those GV relays spare...thanks for that...
mattsd
Super Member
Finally can update this thread! Here is the MC Head Amp Board (F-2833), this board is pretty easy to do relative to most of the others.
Before:
And after! C03, 04, 05 and 06 for the feedback loop were 100uF 25v polarized caps and were replaced with the same value bi-polar caps. The high pass filter caps C07-C10 are 1uF polyester film and were replaced with the same value Panasonic polypropylenes. The local decoupling caps C11-C14 were 10uF 50v and were replaced with 47uF 50v. The trimpots were replaced with Bourns single turn for the voltage adjustment and 25 turn for the minimum THD adjustment pots.
And all done! The original filter caps measured perfectly, so I decided not to restore them right now. Fired it up on the DBT, everything checked out perfectly! Hooked it up on line power, set the bias and offset and also checked for oscillation, scope output and distortion readings were all nominal so I hooked up to my speakers and a source, fired it up and sat back. WOW. Just WOW. Now I see what what people mean when they say the amp is "a wire with gain". It really is, this is a VERY neutral and detailed amp, maybe the best I've heard in those categories. I will be able to expound more once I have listened to it more, but initial impressions tell me this amp is going to do very well with audiophile recordings and anything that was recorded well. I'm running recapped ADS L1230s with it, so it should be quite a test. It also cleaned up beautifully, I would give it a 9/10 for cosmetics.
More to come on how it sounds later!
Before:
And after! C03, 04, 05 and 06 for the feedback loop were 100uF 25v polarized caps and were replaced with the same value bi-polar caps. The high pass filter caps C07-C10 are 1uF polyester film and were replaced with the same value Panasonic polypropylenes. The local decoupling caps C11-C14 were 10uF 50v and were replaced with 47uF 50v. The trimpots were replaced with Bourns single turn for the voltage adjustment and 25 turn for the minimum THD adjustment pots.
And all done! The original filter caps measured perfectly, so I decided not to restore them right now. Fired it up on the DBT, everything checked out perfectly! Hooked it up on line power, set the bias and offset and also checked for oscillation, scope output and distortion readings were all nominal so I hooked up to my speakers and a source, fired it up and sat back. WOW. Just WOW. Now I see what what people mean when they say the amp is "a wire with gain". It really is, this is a VERY neutral and detailed amp, maybe the best I've heard in those categories. I will be able to expound more once I have listened to it more, but initial impressions tell me this amp is going to do very well with audiophile recordings and anything that was recorded well. I'm running recapped ADS L1230s with it, so it should be quite a test. It also cleaned up beautifully, I would give it a 9/10 for cosmetics.
More to come on how it sounds later!
quadklipsh
Super Member
Wow. Just great work , documentation and commentary.
Loved reading it .
Wishing i could get this amp too.
Loved reading it .
Wishing i could get this amp too.
