Sansui AU-555A Rebuild Cap Coupled Goodness
- Thread starter patfont
- Start date
If you are going to replace them use 1N5392 - this is the direct replacement, and is what I would use.
I am not recommending it, but if you want to try an ultrafast recovery type here is one:-
http://www.mouser.co.uk/ProductDetail/ON-Semiconductor/MUR120RLG/?qs=sGAEpiMZZMtbRapU8LlZD9Yt6EMzPspS2typOwY7%2b%2bs=
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jimithng23
New Member
I'm interested in having my 555a recapped/restored as it sounds to me like the right channel is a bit weaker than the left.
I don't have the skillset to do this on my own.... anyone in this thread point me in the right direction?
Thanks!
I don't have the skillset to do this on my own.... anyone in this thread point me in the right direction?
Thanks!
Thanks for your reply!
I am asking because I just read about changing the diodes in this thread
http://audiokarma.org/forums/index....ild-wolf-in-sheep-clothing-in-5-steps.652491/
and "patfont" speaks highly of it.
In the case of the 505 it is a common cathode diode - But would a regular independent diode from the same series be suitable for the 555a ?
Thanks in advance,
Exactly,
then these to diode arrangement looks the same to me except for the different diode types:
Sansui AU555A
Sansui AU505
regards
Jimithing23 I had mine restored by AK member Blaine "Blahgstrom" very reasonable and quick turnaround,He does fine work.
Hello! I used this at sansui au 101:http://eu.mouser.com/ProductDetail/ON-Semiconductor/MURF1620CTG/?qs=Gev%2bmEvV0iZwaH1wwE%2bcvg==
The diodes on the 555 on the left
borrowed picture,
OK well, wired point to point like that gives you plenty of room and no PCB considerations.
Oh wow! those are massive MASSIVE overkill at 16A, and perhaps not wise to use them in such a low powered amplifier.
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smurfer77
Super Member
Nice recap! Enjoyed the discussion of various cap types etc. still amazes me how great these machines are. Right now am listening to the Stranger Things soundtrack and doing a blind A/B/C of a ST-70(with Marantz SC-6 pre)/rebuilt-AU-777A/stock-AU-505 comparison. The 777A is king, but the 505 is pretty magical too. Might have to bring the rebuilt 555A or 505 back into rotation!
On the UFO transistors, I replace them all and have stopped testing them. Aside from complete failure or very noisy and obvious issues, transistors also start to fail or have failure modes which are not total failure, but just get noisy and it is not that obvious at first. Having multiple stock units of the same model made for some interesting comparisons with no input and the volume up comparing the hiss. I've made started collecting noise floor recordings of various amps before and after replacing various components; the UFO (and other transistors) can sometimes be a bit noisy and it's not obvious that it has a problem. Maybe I will do a thread on all of that and rat out the most common culprits and key component locations when I have time to plot noise analysis of the samples. It's also interesting to make recordings or analysis the noise whilst removing various parts of the EM protection in the various amps. Yes, you do need the metal cover over the tone boards in the AU-777 even though it's pretty far from the power supply....(a pity since my AU-777A with transparent lid looks cooler if the preamp cover is removed)
A properly recapped 555A is audio nirvana to my ears. Again, congrats on the beautiful rebuild and congrats to the owner.
On the UFO transistors, I replace them all and have stopped testing them. Aside from complete failure or very noisy and obvious issues, transistors also start to fail or have failure modes which are not total failure, but just get noisy and it is not that obvious at first. Having multiple stock units of the same model made for some interesting comparisons with no input and the volume up comparing the hiss. I've made started collecting noise floor recordings of various amps before and after replacing various components; the UFO (and other transistors) can sometimes be a bit noisy and it's not obvious that it has a problem. Maybe I will do a thread on all of that and rat out the most common culprits and key component locations when I have time to plot noise analysis of the samples. It's also interesting to make recordings or analysis the noise whilst removing various parts of the EM protection in the various amps. Yes, you do need the metal cover over the tone boards in the AU-777 even though it's pretty far from the power supply....(a pity since my AU-777A with transparent lid looks cooler if the preamp cover is removed)
A properly recapped 555A is audio nirvana to my ears. Again, congrats on the beautiful rebuild and congrats to the owner.
tyeeslayer
Super Member
The Fuxtor
Addicted Member
I'm thinking the Sanyos might be an earlier version??....
