Sansui AU-555A vs. AU-666

I own a TU-666 and a AU-555A (grandpa's inheritance), but I would like to know how different (soundwise details) the ampliflier is to the AU-666. This amplifier is scarce and there is few information about it and the 555A is regarded so highly. Why?

Here's a look at the AU-555a...it's gorgeous:

http://www.youtube.com/watch?v=WXsGNVtS4sw

The speakers aren't connected in the video, so I don't think we're hearing the actual amp. I've not heard one in the real world.

I owned a AU555A a few years ago.
Now I have an AU666

The main difference between the two is the AU666 have 2x35 watts instead of 2x25 for the AU555A.

The AU666 is technically (a little bit) more advanced, it has a "complementary" output stage and no output capacitors, it is slightly more complex (maybe 30% or so more parts).

Those Sansui amps are a little bit "over-hyped" but I guess they are better than average comparing to most (but not all) amps of about the same amount of watts produced at the same time.

I doubt if there is much difference between an AU555A and a 666 sonically, I do remember also the AU555A sounded very nice. The 666 sounds good but I did not listen more than an hour or so up to now.

If you do not need the power, just go with the 555A, if you lack just a little bit of power (which depends on your preferences, loudspeaker efficiency and room size) the AU666 will give you definately this little bit more.

here some pictures of my au666 http://members.quicknet.nl/gerard.slikker/sansuiau666.htm

Thanks for the information and sharing the links.

Those Sansui amps are a little bit "over-hyped" but I guess they are better than average comparing to most (but not all) amps of about the same amount of watts produced at the same time.

Which ones do you consider are the best?

You will always have to trade price against looks, build quality, quality of the electronics, performance of the electronics, presumed or real reliability and the way you use it, possible sonical flaws, and maybe more.

People having a turntable, when buying an old vintage amp, may regard an amp with lowest noise and hum and at least no audible distortion of the phono stage as "best". Maybe the simple phonostage design of those early amps would give quite some differences between different amps which are audible. I can not judge, while I have no turntable.

Other people prefer "much bass" and they regard amps where you get a little extra bass even with tone controls centered as "better". Where this "better" could just be a different behavior of a loudness knob...depending on volume.

IMHO, there is no "best".

Of course Gerard is right, there is no "best".

Regarding the question, I restored an AU-666 some while ago for a customer. I thought it sounded very very nice and the customer agrees. But I also recently bought an AU-555A. I need to say I really like the "capacitor coupled" sound, precisely what the Marantz 1060 is so famous for. Still, this particlular example is "droning" a little. Perhaps it is because it had not been used for some thirty (!) years according to the former owner, so the caps might not be optimal anymore. It also might be the combination speakers/amp not being optimal. Still, apart from this little droning it sounds very musically and I would not be surprised if a recap will take care of this droning to make it sound perfectly.

I bought this amp as broken btw, it appeared someone exchanged the mains plug but forgot to connect the wires.... . Still, when connected it only had sound on one channel, the tape monitor switch was responsible here. A (very thorough) deoxit solved that and now it plays fine. It's always nice if a repair is that simple

jeromach said:

Of course Gerard is right, there is no "best".

Regarding the question, I restored an AU-666 some while ago for a customer. I thought it sounded very very nice and the customer agrees. But I also recently bought an AU-555A. I need to say I really like the "capacitor coupled" sound, precisely what the Marantz 1060 is so famous for. Still, this particlular example is "droning" a little. Perhaps it is because it had not been used for some thirty (!) years according to the former owner, so the caps might not be optimal anymore. It also might be the combination speakers/amp not being optimal. Still, apart from this little droning it sounds very musically and I would not be surprised if a recap will take care of this droning to make it sound perfectly.

I bought this amp as broken btw, it appeared someone exchanged the mains plug but forgot to connect the wires.... . Still, when connected it only had sound on one channel, the tape monitor switch was responsible here. A (very thorough) deoxit solved that and now it plays fine. It's always nice if a repair is that simple

Click to expand...

I just fixed up an AU-555A: caps, transistors, pots, and a few other things. Bumped up the filter and output caps, replaced electrolytics with films where practical, new mica and grease on the final trannys. It's easy to work on. I think it sounds great, and it seems to have more oomph into my efficient bookshelf speakers than my 30W Marantz 2230, also cap coupled, had.

I ran the two side-by-side for a couple months and ended up selling the 2230.

I have rebuilt both 555A and 666 and listened to them extensively (I've owned a 666 since I was born believe it or not . I own three AU-666, and six 555A/505. If you search my posts you can see some pics of rebuilds of both.

As mentioned the 666 has a bit more power, but the 555A is likely to be plenty loud unless you have inefficient speakers.

Contrary to some previous posts I think that the amps of this era are quite special. I came back to them after owning >$10k amps, and am happier than ever. But as one previous poster wrote, there is no best... but just different.

Also contrary to previous post the AU-555A sounds quite different to the AU-666 IMO. It IS similar in some ways, yet the 666 is far less warm in tonal quality than the 555A. YMMV with mods/refurbs of course (in particular output coupling caps on the 555A). The 666 is schematically closer to the AU-999 than the 555A, and it sounds it (I own au-999 as well).

Both have tone controls, and you can adjust to your tonal preference as you prefer... so maybe this is all a bit moot.

Both are great amps.

smurfer77 said:

I have rebuilt both 555A and 666 and listened to them extensively (I've owned a 666 since I was born believe it or not . I own three AU-666, and six 555A/505. If you search my posts you can see some pics of rebuilds of both.

As mentioned the 666 has a bit more power, but the 555A is likely to be plenty loud unless you have inefficient speakers.

Contrary to some previous posts I think that the amps of this era are quite special. I came back to them after owning >$10k amps, and am happier than ever. But as one previous poster wrote, there is no best... but just different.

Also contrary to previous post the AU-555A sounds quite different to the AU-666 IMO. It IS similar in some ways, yet the 666 is far less warm in tonal quality than the 555A. YMMV with mods/refurbs of course (in particular output coupling caps on the 555A). The 666 is schematically closer to the AU-999 than the 555A, and it sounds it (I own au-999 as well).

Both have tone controls, and you can adjust to your tonal preference as you prefer... so maybe this is all a bit moot.

Both are great amps.

Click to expand...

have you heard an au-717? if so is it closer to the 555 or 666? Thanks

Hi,

AU 717 is totally a different era although it still has the warmness of the older amplifier such as AU 666/555A. The sound reproduction is very accurate and clean and AU 719 is much more cleaner or they called as "neutral". I still love the sound of my AU 777 earlier.

59volvo said:

have you heard an au-717? if so is it closer to the 555 or 666? Thanks

Click to expand...

As the other poster says, the 717 is a different beast but it is also a great amp with some of the vintage sansui tonal quality lost on some of the newer models (IMO).

Would a 717 be better than a 555A or 666? I don't know. They are all great, with different qualities. Just take the plunge on one

I missed the main conversation on this I know, but I came across this as I am looking to part with my 555a. Not for any sonic reason, just that I now have too much stuff and this is one I can part with. My question is regarding the toggle switches - in particular the mode switch for stereo/mono. Mine broke off last year, and although I know I have the little arm around here somewhere, it's best to put a new switch in I think. Any of you guys that have done re-caps and new pots, etc. know what I should use to replace that toggle switch? The Rat Shack ones don't have arms long enough to get the little end cap on.

I hope no one minds that I'm hijacking this thread, the conversation seemed to be over.

I just acquired an AU-666 and it's gorgeous for it's time. The fact that they provided separate bass/ mid-range/ treble controls for each channel is definitely unique and shows how they were "Ahead engineering" their components even over 50 years ago.
Well built for sure. Absolutely love their simple, refined and clean-industrial looks, too.
This joins my AU-9900, TU-9900, CA-3000 and BA-3000.

Can anyone tell me if the AU-666 has any Black Flag caps?

Majestyk said:

Can anyone tell me if the AU-666 has any Black Flag caps?

Click to expand...

Negative!

Chuck Vance said:

I just acquired an AU-666 and it's gorgeous for it's time. The fact that they provided separate bass/ mid-range/ treble controls for each channel is definitely unique and shows how they were "Ahead engineering" their components even over 50 years ago.
Well built for sure. Absolutely love their simple, refined and clean-industrial looks, too.
This joins my AU-9900, TU-9900, CA-3000 and BA-3000.

Click to expand...

I have one, too, and it's just so nice (I had it rebuilt several years ago). It drives my little Rega Aras beautifully.