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AU-999 Recondition complete......WOW.....

kevzep

kevzep

Its all about the Music
Well Ive finally finished the 999, new electrolytic caps from one end to the other, all the transistors from one end to the other have been replaced, not one of the old ones left in the amplifier......

I went to 10,000uf main caps, put a bigger bridge rectifier in it......

Recapped every board including the speaker protector board, deoxited everything......

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So I ran it up with very very pleasing results, the thing just revealed amazing detail in the sound......NOTHING like it was before, the bass is tight and even, everything is clean and clear all the way up the through the mids to the most delicate top end, very nice.......:yes:

Its very punchy for its 50watts, I was so impressed with the sound I thought I would put it on the 4412 JBL's in our studio setup we have, I have a QSC powerlite 1.8 on the 4412's and have always thought it was doing a fine job......well, both my girlfriend and I prefer to mix on the AU-999, theres something about the linearity and clarity in this amplifier we really like....and its capacitor coupled....go figure...:scratch2:

So there it is, it stays on the studio monitors, and you know 50watts is totally enough power to do our mixing with......
My girlfriend, who writes the songs and does most of the mixing just loves it....who would have thought.....an amplifier nearly 40 years old would be so impressive.....
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Thanks Guys, yes Im very pleased with it.........

Its a very smart looking and sounding amplifier, those Sansui designers sure had something to be very proud of....:thmbsp:
 
kevzep said:
Thanks Guys, yes Im very pleased with it.........

Its a very smart looking and sounding amplifier, those Sansui designers sure had something to be very proud of....:thmbsp:
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Kev, great going. In my opinion, the AU999 might be the best amp Sansui ever made. It's kinda a toss up between that and the AU9500. Of course, the 9500 has a little more power. If you're using that as you mixdown amp, I'd like to make an addition to it, if you're interested. PM me your address, and I'll send you everything to add the differential amp mod that I do, with instructions on how to do it. I'm working on an AU999 right now, and I'll make you an extra set of sources for the diff pair. It will make the AU999 even better.
 
Hey Kev,
My son has got our AU999 all apart and mostly recapped. This one has the flying saucer Tr's throughout. I think the other one I did before didn't. I've heard lots of not so good things about them. Do you happen to have a list of replacements? If it sounds less than perfect when we bring it up, I just might go through and do what you did and change out all the Tr's.

Jim
 
Trnsfmr said:
Hey Kev,
My son has got our AU999 all apart and mostly recapped. This one has the flying saucer Tr's throughout. I think the other one I did before didn't. I've heard lots of not so good things about them. Do you happen to have a list of replacements? If it sounds less than perfect when we bring it up, I just might go through and do what you did and change out all the Tr's.

Jim
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Yeah Sure Jim, it pretty simple.....there are eight different transistors in the 999......I used MJ15024 TO-3's for the outputs....some of mine had been replaced, so i wanted them all the same.
Dont worry about the thermal regulator TR809 2SC281, or the driver transistors, they are silicon so they will be fine.
The large 8002 and 9002 flying saucers were MJE350 and MJE340 and the X495 smaller flying saucers, I used 2N5087G......
There was a 2SC458 in the front end which was silicon, so i left that one in....its in the Phono/Mic pre.......

I was a bit anal, and matched the hfe on my meter, I bought a big bunch of transistors so I could get them all pretty close.....
 
Those 2SC458's are those noisy unreliable trannies Kev - I think you should swap them with 2SC2240's ?
 
Nice work Kev! I bet she sounds great.

Are those electric blue caps the Panasonic ECA 'audio' caps? If so, I've been using those on a few amps here and there and they seem to do the job pretty nicely.
 
Hyperion said:
Those 2SC458's are those noisy unreliable trannies Kev - I think you should swap them with 2SC2240's ?
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Tell you what I havent actually used my turntable through the phono inputs, but I think I will swap em out, looks like a good sub, I will take your word for it.... Thanks for that...
pete_mac said:
Nice work Kev! I bet she sounds great.

Are those electric blue caps the Panasonic ECA 'audio' caps? If so, I've been using those on a few amps here and there and they seem to do the job pretty nicely.
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yes they are, they seem to do the job well.........
I am very pleased with it........
 
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Oh man. That's what I need to do to mine...Only, I have no idea where to start...

I have been looking for a set of 4412s for a good while now to go in my home studio that I'm putting together. Good to know that someone besides me thinks it's a good match.

Congrats on the work. I bet it's even more fun to play with now. I love mine. Classic styling, clear sound. Such a good amp.
 
Nice to see good results. I've got an AU-999 on the shelf right now I was thinking of selling because it sounds rather poorly compared to the other Sansui amps I have... I knew a recap would help but was unsure if it was worth all the trouble as I have been eyeing some AU-9500's.
Funny thing about all this studio talk is I was thinking my AU-999 would have made a good match for my 4411's in my studio... but was really disappointed in it's current harsh soundstage.
Any studio guys here use Yamaha NS10m studio monitors... and what do YOU use to power them? I currently use a Hafler on mine.
 
kevzep said:
I was a bit anal, and matched the hfe on my meter, I bought a big bunch of transistors so I could get them all pretty close.....
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Thanks, sounds pretty simple. For an amp of this quality, I would match the HFE's also.

Did you get my email about your address? I sent it back to your actual email adress, not the AK, PM method.

Best,
Jim
 
Trnsfmr said:
Thanks, sounds pretty simple. For an amp of this quality, I would match the HFE's also.

Did you get my email about your address? I sent it back to your actual email adress, not the AK, PM method.

Best,
Jim
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Yes it is simple, love working on this amp, the boards plug in everything in easy to get at.......
No dangerous DC voltages like the crowns............Or the Bass amp I was fixing yesterday which had 2x GEC KT88's in the poweramp section making 100watts, 700VDC on the plates!!!! Ouch.......I was careful working on that thing I can tell you.....

For that little NPN in the Phono pre I eneded up with a BC63916 Fairchild......the one Hyperion suggested was obsolete, but easy enough to find a sub......
 
kevzep said:
For that little NPN in the Phono pre I eneded up with a BC63916 Fairchild......the one Hyperion suggested was obsolete, but easy enough to find a sub......
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Whoops sorry Kev - I bought some a couple of weeks ago - I was not aware they were actually obsolete :o
 
Hyperion said:
Whoops sorry Kev - I bought some a couple of weeks ago - I was not aware they were actually obsolete :o
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No problem, theres always perfect substitute, thanks for the heads up on those noisy transistors, I did notice there was a bit excess hiss on the phono input when I tested it, so that will take care of that.....
 
Great job on that AU-999 Kevin, I'm not surprised that the sound has been totally transformed into something really great! Sansui were ahead of their time that's for sure in every aspect, if you compare a Pioneer from the same period and of similar league, the Sansui leaves it for dead.
Those old caps in the 999 would have been one of the contributing factors to it sounding a bit dull, in my AU777 that I overhauled about 2 years ago, gradually replacing the electros, I could hear it improving the further I went through and then all the transistors expect drivers/outputs and wow it really came alive and sounds so dam nice! I checked all the old caps on my ESR meter and they were all so out of tolerance it wasn't funny like a 33uf reading close to 70uf and a 1uf reading about 5uf and the ESR values reading higher than normal too. So those old grey Elna caps have a lot to answer for! :D

Cheers...

PS Did get your email and have been meaning to reply with some interesting things hifi related but have been busy of late, but will get there. :)
 
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