The Mighty AU-X1

Now that I’ve been listening to the X1 for long enough to get a feel for it, I thought I’d post some of my impressions for anyone that might be interested.

For starters, I like the fact that the X1 does not have tone controls. Over the years I've become accustomed to a “flat” presentation. When my amps do have tone controls I always play them flat anyway. It’s what I prefer. If you like a “tweak” or “boost” of certain bandwidths this may not be the amp for you. That’s probably why when I initially (briefly and cautiously) listened to the X1 (pre-restoration) I was encouraged. I could hear the unaltered sound I like. With that said, the restoration made clear improvements and allowed this amp to show its full potential. I haven’t had the time to take it out of the rack and take pictures of the interior work. I’ll get to that soon.

Apologies in advance for this long post. If you prefer not to read through the rest, the takeaway is that the hair on the back of my neck and forearms has stood on end at least 5 times since I started giving it a careful listen. This amp is an enigma, it lets you feel the music and still lets you hear all the fine detail that is there. It’s like a hybrid between an emotional amp and an analytical amp. It seems to deliver both attributes without sacrificing either. That’s a unique combination. This is a head bobbing, goosebumps kind off amp.



Here are some thoughts I had as I listened:

-Amazing soundstage. It’s not only very wide but it’s deep. The perception of depth and height is great, you can sense the room where the content was recorded. There’s a pinpoint dimensionality with the placement of the instruments surrounding the vocalist. In some instances I could sense the musician slightly swaying to the left or right as they played almost as if they are leaning or slightly turning their body. Hard to explain. In some cases some of the instruments are projected into the soundstage, closer to the listener. This should not to be mistaken with a forward sounding amp which in my opinion the X1 is not. Soundstage (width-wise) this amplifier almost made my conventional speakers sound like SDA-SRS speakers. That say’s a lot.

- The bass is either there or it’s not. It’s in and out just like that…all business. There’s absolutely no overhang.

- Control is the word that came to mind to describe how it handles highs. It’s like the amp can take the highs as high as they require - right to where they should be, and holds them there, maintains a grip on them then pulls them back when needed. Very smooth. There are no run-away highs. No harshness or stridency.

-Midrange is very natural and clean. Initially during the first few days of listening I had trouble getting pinpoint imaging from the vocalist. It was like the voice was coming from a space about a foot wide as opposed to 2 inches wide. It’s the only thing that struck me as “wrong” about the presentation. That concerned me, I fiddled with my speaker placement but ended up returning them to their original position. After a few days of auditioning one day I turned on the amp and it just happened… the vocal imaging was razor sharp with pin-point placement. This improvement wasn’t in my mind or that I got used to it because until it happened all I kept thinking was- bummer, I gained a huge soundstage but lost the vocalist. Not sure what it was but luckily it resolved itself. Vocalist are “right there” as they should be.

- This amp has a very clean sound, there is no perceived “reverb” for lack of a better term. There is no “filler’ with this amp. Since I’m used to listening “flat” I think I’m very sensitive/perceptive of that “reverb/filler/hum” thing.

-Silence and a blank background are very noticeable.

- In some ways I expected this amp to sound cold and clinical due to its design goal of being the ultimate in the pursuit of a “wire with gain”. I was surprised to find that this amp is extremely musical and involving all while being highly resolving and as I mentioned earlier very, very clear.

- Here’s a weird one, the music sounds slower (in a good way) not in its attack which is awesome but in the fact that the music is not hurried or rushed. It’s like every sound has its place and makes itself known so you can savor it better.

- I noticed that faint hi-hat, cymbal taps and snare drum wire vibrations were making themselves known. Not in an obtrusive way, they were just noticeably there keeping the pace of the music and not lost in it.

-The volume knob is not detented which is nice because it allows for precise volume control. At first turn of the knob, the amp seems sedate. You get the impression that the pre-amp doesn’t give the initial boost that some amps give you early on. That along with how clean the X1 plays can be deceiving. Some amps give you all the goods upfront, not the X1. As you turn the volume up all you get is more music. That’s when you realize how powerful and clean this machine is. The best way I can describe it is to paraphrase my tech who warned me to be careful, this thing is like a Ferrari he said. Turn that volume knob up and zip---you won’t even realize how much power you are pushing because it is so clean.

-Due to WAF and other reasons, a while back I put my large floor-standers in storage and I’ve been using modern stand-mounts that go down to about 50 Hz. I’ve been very satisfied so far. But this amp puts on such an immersive presentation that I’m considering adding a sub or two because I want to see how it handle that last 30 Hz that I’m missing.


More to come…
 
Your description of the AU-X1s performance is "right on the money".
I did a listening test of mine Friday night and I fully concur with you assessment.

While working on the amp last night I had to remove the knobs to get to the flat amp to install a new main volume control pot which I had just reconditioned.
Doing this job reminded me of a small point that exhibits the absurd amount of quality in this machine...all the knobs are solid aluminum.

That crazy bit of of high quality excess is so what this amp is all about.
 
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In the 1970's, solid aluminum knobs came to be an expected feature for any amp presented as quality, even quite inexpensive ones. I have a Sansui 221, the lowest-end vintage Sansui there is, and it has metal knobs.

OK, not solid metal, metal over plastic inserts, but definitely a 'solid aluminum feel....'
 
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Yes...true. The AU-9900 I have sports full metal knobs too.

The AU-X11 from 1982 used the same knobs as the X1. BUT I have an AU-907 from the same year as the X11 that opted for hollowed out ones.
 
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I feel like I just read a review from "THE ABSOLUTE SOUND" about a Soulution amp.
A great review! Where are those pics?
 
I bought the only one I've ever seen in the flesh.
It weighs about 10 lbs MORE than an AU-20000. :eek:
 
It seems that whenever I have time, I start listening and then I don't want to stop for long enough to unplug this behemoth to take pictures. The hours fly by.

Over the last few days I've been listening to vinyl through one of the MM stages. It sounds excellent. I don't have many records but I do have two brand new 180 gram LP's that sound amazing. It's hard to believe how good a clean high quality pressing can sound. Wow! I can see myself getting a decent MC cartridge in the future just to hear what that board sounds like with those 14 in-line FET's.

Here are a few pictures on the bench before the restoration (I'll get to the after pictures soon):

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More to come...
 
Is the dis-assembly your handiwork, or are those pics from your tech?

Very educational BTW.

(The SS-5 and SS-5R diodes look new. Hmmmm)
 
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Is the dis-assembly your handiwork, or are those pics from your tech?

Very educational BTW.

(The SS-5 and SS-5R diodes look new. Hmmmm)

These are picture's my tech took on his bench. It's possible that he had already replaced some components when he took them. His report did say something about him replacing varistors or diodes, I'll have to look.

I plan on finally taking pictures this week, we'll see how they compare. Hopefully I can get a few decent shots to highlight some of the work that was done.
 
These are so rare to see.....and let alone as nice as this? Pure unadulterated......"place adjective of choice here". (Damn thing caught me up short for one.) Enjoy!
 
Your listening impressions of that fantastic amp is salivating!! The dream of every audio purist.
The "before" pix show a VERY clean interior.
Why would you want to dismantle such a finely restored and reassembled masterpiece, just to get some "after" pix?
Please don't get me wrong ... I would also love to see the "afters" ... but ...
Congrats and enjoy.
Robert.
 
Congrats man, this is a first class report and read.
Naturally tis is a first class AMP.I feel justified for shouting all these years that AU-X1 is the finest amp sansui has made.This and the combos 2301 2302.
Greetings.
 
This thread took me back, I had one of these in 1979 for 5 or 6 years when I was a student. I worked for a Sansui dealer so got it at trade price. I live in the UK and it was imported specially for me from Japan and I remember waiting for a long time for it.

It fried my speakers as the power output (160w rms, 350w peak I think) was much greater than my Kef 104ab speakers could handle. I never used to it's full potential as I lived in a student house and then when I got married I lived in a house that wasn't detached and it wasn't polite to shake the foundations for the whole block.

I sold it for very little money to a person who had no idea what he was buying: poor guy I am sure that he would have blown his speakers too.

I wished that I had kept it as it only now I think my setup is better: (Cyrus X200 monos x2)
 
I'm just very happy to have the lower powered version of the X1 which is the 919. I just had a very exciting listening session after mounting my new Grado wood-body on my SOTA Sapphire through my Vandersteens!
 
As an added bonus it seems that the MM and MC stages in this amp are excellent. I've been educating myself specifically on the aspects of MC phono stages and it looks like the one in the X1 is very impressive. As I said earlier, the MM stage sounds amazing, makes me want to go out and buy records. I'm looking into getting a high quality LOMC or LOMM cart to hear what the MC stage can do. I can't wait.

BTW, I'm finally posting some interior shots later today.
 
Yes, I believe the MC section on the X1 is better than the 919. It's completely Direct Coupled but the 919 isn't. I'm using the low output version of the Grado wood-body so I'm using the MC setting for that. However, I had to change some resistors on the MC board to get 47Kohms for the Grado. Echowars told me the resistors to use.
 
Yes, I believe the MC section on the X1 is better than the 919. It's completely Direct Coupled but the 919 isn't. I'm using the low output version of the Grado wood-body so I'm using the MC setting for that. However, I had to change some resistors on the MC board to get 47Kohms for the Grado. Echowars told me the resistors to use.

That's interesting, I would've thought they'd be the same because it seems the 919 also has a .1 mV input sensitivity. I think the ohm rating may be different. I'm trying to learn all the variables of MC stages so I can understand what I have in this thing in comparison to external phone stages and SUT's.
 
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