New AU-D11II

[Zekeman]

I'll have to continue to listen now that it is off the bench. I am listening to it alot in my basement. The amp sounds extremely pure and accurate. The 717 has a slight "sizzle" quality that seems to have been mellowed a bit in the D11. High volumes are devoid of distortion (although I have not had it beyond, say, 11-o'clock).

Thanks for the interest. BTW Riverrat, did you ever get your back from being reconditioned?

 

[riverrat]

I just spoke with quadbob again yesterday.

He did a complete recap, except for the main power supply caps and completed that part of the restoration awhile back. He told me the main caps were in pretty good shape and the amp would probably serve me well for several years. He said that replacing the main caps was technically not necessary, but if it were HIS amp, he would go ahead and replace those too.

We all know the risk (and cost) involved with shipping our precious vintage components around, and once I get this one back, I do not want to ever ship it anywhere again! So I elected to have him replace the main caps as well- overkill maybe, but it made sense to me to have this done while he had it there.

But the first ones he tried did not fit. So he had to source some different ones from Canada. It has taken so long to get those that I was about ready to just have him ship it back "as is". But he said yesterday that he finally heard back and that the new main caps are on the way Fed-Ex. So he should have the work completed soon. I am VERY eager to get it back and find out how it sounds!

Here's a pic he sent:

 

[reggaenaut]

The wide variation in evaluations of this amp is interesting, and leads me to think that there must also be variation in how each unit sounds, perhaps related to cap condition and accuracy of DC offset settings. There have also been the controversial suggestions that replacement of certain caps on this unit can actually degrade sound quality.

I personally do not buy into that position, but sometimes I wonder...why would some people who are very experienced with many other high end units think this amp is so special, while others do not?

The disparate evaluation is probable a result of the myriad adjustments required for the amp to operate properly.

 

[mjs1]

Sansui AU D11II

With all due respect to my fellow AKers and most certainly to Bigerik, riverrat, and reggaenaut this is the point of view of a relative novice.

I love the Sansui integrateds in part because they are great, in part for their looks, and because when I decided two years ago to get into vintage, I happenned to come across a Sansui, the AU 717. As best I know, EchoWars is partial to the Kenwood 700s, dr*audio loves his AU 9900 but his favorite amp was his Onkyo (I'm doing this from my recollection of old posts, please forgive any inaccuracies). For a while, I was only partial to the the integrateds with black knobs but now have an AU 9500 and AU 11000. I also have an EchoWars D11II, 3 717's, 2 919's, and a G99X, and and a BA 2000 which I run off the AU 11000 pre-amp. I also have a switchbox and can choose between the amps by pushing a button. I'm 59 years old, know that I have hearing loss, only listen with Boston and Infinity Kappa speakers, and only listen at moderate volumes. FWIW, I doubt that I can pass a blind listening test and choose between these. I am happy to listen to any one of these, and rotate them. Even with a switchbox the louder one usually sounds better, without one and working on recollection it is even harder to compare them.

The AU D11II sounds great and I'm told that it sounds better with newer improved op amps. But, I just don't believe it's vastly better than any of the others and I don't think that differences can be attributed to the trim pot adjustments. It's more a matter of the individual, the moment, the setting, or just making up our minds that this is the best, or that Sansui is better than MacIntosh (I have never heard a MacIntosh, it's just that I happenned to get interested in Sansuis, likely because they were cheaper). Love it all. This having been said I would love to have an AU-X1, AU-X11, AU-X1111, an AU-20000, and a CA-F1 just like Rex Everything's.

Marc

 

[Zekeman]

Well said mjs1.

What amplifier switch are you using to change the amp/speaker combinations?

Thanks.

 

[mjs1]

Sansui AU D11II

Hi Zekeman

I won't be able to check out the switchbox until tomorrow but it came from ebay, was sold by a former audio dealer, and can choose between 2 inputs, 20 amps and 20 speakers.

Marc

 

[Duffinator]

Hi Zekeman

I won't be able to check out the switchbox until tomorrow but it came from ebay, was sold by a former audio dealer, and can choose between 2 inputs, 20 amps and 20 speakers.

Marc

That sounds cool. Another AK member bought this really trick one like that and it was made by Yamaha.

 

[reggaenaut]

With all due respect to my fellow AKers and most certainly to Bigerik, riverrat, and reggaenaut this is the point of view of a relative novice.

I also have an EchoWars D11II, 3 717's, 2 919's, and a G99X, and and a BA 2000 which I run off the AU 11000 pre-amp. I also have a switchbox and can choose between the amps by pushing a button. I'm 59 years old, know that I have hearing loss, only listen with Boston and Infinity Kappa speakers, and only listen at moderate volumes. FWIW, I doubt that I can pass a blind listening test and choose between these. I am happy to listen to any one of these, and rotate them. Even with a switchbox the louder one usually sounds better, without one and working on recollection it is even harder to compare them.

The AU D11II sounds great and I'm told that it sounds better with newer improved op amps. But, I just don't believe it's vastly better than any of the others and I don't think that differences can be attributed to the trim pot adjustments. It's more a matter of the individual, the moment, the setting, or just making up our minds that this is the best,

Marc

I have to respect your experience. I have never listened to the amp in question, but have been told that it is troublesome to adjust.
By the way I am partial to au919. I have listened to this one(now in need of repairs) for many years and it is satisfying to know that you could not differentiate between the amps.

 

[joemango]

The wide variation in evaluations of this amp is interesting, and leads me to think that there must also be variation in how each unit sounds, perhaps related to cap condition and accuracy of DC offset settings. There have also been the controversial suggestions that replacement of certain caps on this unit can actually degrade sound quality.

Re: cap condition

Though I don't have an AU-D11II, I strongly believe there are no electrolytic capacitors in the signal path since the design is true DC. I have the later generations of this amp and all of them have no electrolytic capacitor in the signal path. All electrolytic capacitors were strictly used for DC bypass and filtering only. If you are listening to vinyl then there is a DC blocking capacitor on either the phono preamp input or output. Recapping all the electrolytic capacitors on any of these amp would improve long term reliability but not necessarily the "sound".

Re: DC offset

Every now and then DC offset has been attributed to the audio quality of an amplifier. As far as amplifier distortion mechanism is concerned, output stage DC bias is one of the parameters. Fact is, DC offset is not one of them. An amplifier with a DC offset of 0.5mV will sound the same as one with a DC offset of several tens of millivolt. If you trace the audio chain from the CD player all the way to the power amplifier output for example, each gain block (DAC amp, line amp, preamp, power amp) has its own DC offset. Note that the commonly used single transistor class A preamp block will have 1/2 Vcc DC offset on its output. I'm not all convinced that a 50mV (~0.3mW) DC offset superimposed on a 12" 8 ohm woofer is significant. The woofer would be constantly displaced by say +/-0.25mm but this is insignificant if one considers the tolerance in loudspeaker manufacturing. If that was a 50mV 60Hz hum it will be clearly audible but we are talking about DC offset.

Re: amplifier comparison

Audio is very subjective in nature. The audio source, level, room acoustics, ambient temperature, humidity, speaker, speaker placement, and finally the listener's musical taste, ear, health and mood play a role in the final outcome of a listening test. Any of these can vary from person A to person B so the results will never be identical.

My 3 cents.

 

[riverrat]

With all due respect to my fellow AKers and most certainly to Bigerik, riverrat, and reggaenaut this is the point of view of a relative novice....

No offense taken, at least not by me! You raise some good points.

My AU-819 and 919 are better built and I could be happy with either of them, but the AU-D11 II is still nicely made and to my ears sounds somewhat more open and clean. And the latter amp finally helped me start to understand what people mean when they say an amp is "fast". But a double blind test might very well debunk these perceived differences with me too, who knows- I agree that the differences are not vast, at least not in my system.

It's been fun learning from people here and trying to figure out what components to settle on. I'm not ready to admit that the power of suggestion is all that has guided me, but that has certainly been part of it. I'm not immune to the power of suggestion in areas where I'm not an expert, from others who I perceive as more experienced than I am.

In any case, I foresee a gradual wind down in my recent obsession with 2-channel audio and reducing my array of gear. It is becoming increasingly apparent to me just how complex digital photography is, and how much I have to learn if I want to get on, and stay on that train.

Most of my spare time in the near future will probably be spent learning about digital image post-processing and scanning my multitude of slides, rather than discussing the merits of different audio equipment. But I'll still lurk and chime in on occasion!

 

[riverrat]

Every now and then DC offset has been attributed to the audio quality of an amplifier. As far as amplifier distortion mechanism is concerned, output stage DC bias is one of the parameters. Fact is, DC offset is not one of them.

joemango, I think I meant to say DC bias, but I do not really know what I'm talking about, so perhaps I should not have speculated about this. What I do know is that some people feel this amp is in a league of its own, while others seem to wonder what the big deal is. I guess I fall somewhere in between- its my favorite among the limited number I've tried in my system but I can't say it was a jaw-dropping improvement over the AU-819 and 919.

RE cap replacement and improved sound- I guess I will see. I've heard so many different opinions I don't know what to expect, although there does seem to be general agreement that cap replacement is a good idea from a reliability standpoint.

The amp sounded very nice before I sent it off for refurbishing- the primary reason I did so was to address some intermittent, low-grade humming that did not come through the speakers, but rather emanated from the amp itself. Curing the hum and assurance of better long-term reliability would be benefit enough, further improvement in sound would just be icing on the cake!

 

[EchoWars]

Re: cap condition

Though I don't have an AU-D11II, I strongly believe there are no electrolytic capacitors in the signal path since the design is true DC. I have the later generations of this amp and all of them have no electrolytic capacitor in the signal path. All electrolytic capacitors were strictly used for DC bypass and filtering only. If you are listening to vinyl then there is a DC blocking capacitor on either the phono preamp input or output. Recapping all the electrolytic capacitors on any of these amp would improve long term reliability but not necessarily the "sound".

The AU-D112 II uses a couple of back-to-back 33uf 16V electrolytics bypassed with a 0.047uf film cap at the output of the phono amp. You are correct...the rest of the amp is fully DC coupled. The rest of your statement comes close to suggesting that swapping the rest of the caps is nearly a wasted effort. If that's your meaning, I could not disagree more. They are old caps...no further reason is necessary.

Re: DC offset

Every now and then DC offset has been attributed to the audio quality of an amplifier. As far as amplifier distortion mechanism is concerned, output stage DC bias is one of the parameters. Fact is, DC offset is not one of them. An amplifier with a DC offset of 0.5mV will sound the same as one with a DC offset of several tens of millivolt. If you trace the audio chain from the CD player all the way to the power amplifier output for example, each gain block (DAC amp, line amp, preamp, power amp) has its own DC offset. Note that the commonly used single transistor class A preamp block will have 1/2 Vcc DC offset on its output. I'm not all convinced that a 50mV (~0.3mW) DC offset superimposed on a 12" 8 ohm woofer is significant. The woofer would be constantly displaced by say +/-0.25mm but this is insignificant if one considers the tolerance in loudspeaker manufacturing. If that was a 50mV 60Hz hum it will be clearly audible but we are talking about DC offset.

The offset itself is not really the problem, per se. The real issue is the imbalance of the differential pair transistors (assuming the amp uses them, and most amps have a differential pair in their input/feedback stage), and that's where distortion mechanisms come into play. I can easily measure distortion increases by purposely unbalancing an input stage as little as 25mV.

Re: amplifier comparison

Audio is very subjective in nature. The audio source, level, room acoustics, ambient temperature, humidity, speaker, speaker placement, and finally the listener's musical taste, ear, health and mood play a role in the final outcome of a listening test. Any of these can vary from person A to person B so the results will never be identical.

Well put.:yes:

 

[reggaenaut]

Most of my spare time in the near future will probably be spent learning about digital image post-processing and scanning my multitude of slides, rather than discussing the merits of different audio equipment. But I'll still lurk and chime in on occasion!

It is nice to know that you are not leaving us but will be lurking. I always appreciate your input.

 

[Duffinator]

Great discussion going here, please keep it coming.

Clearly it's a good idea replacing caps on these 20 plus year old pieces of audio equipment from a reliability standpoint but I've heard mixed results when it comes to improving sonic quality. But I'll find out when I have my Pioneer SX-1250 gone through the first of next year.

riverrat, I've enjoyed your insightful posts and opinions and hope you continue to lurk and post often. :yes:

 

[Zekeman]

I like this....this is probably my most successful post, in terms of response.

 

[UpsideThe Head]

I'm glad your happy with the AU-D11II. I am very lucky in that when I got
mine back from the Hi-Fi Hospital it was spot on perfect and has worked that
way ever since. All original parts, just a cleaning and adjustment. I have a
second one there now which I can't wait to get back as well.
Why did you decide to use a separate power amp? I always thought the
AU D-11II power amp sounded so quick, clear and clean. It was what I thought made this amp.

 

[bobrown14]

AU-D11 II side by side comparison

My results are from a side by side comparison of the AU-719 and the AU-D11 II. What happened to me was a near nirvana state when I first took a listen to the AU-D11 II. Wow what a clean crisp sound at all volumes. I compared that to the 719 which I had previously thought sounded the best ever. There was a vast improvement in low volume clarity with the AU-D11 II. At higher volumes the 719 catches up but I don't really crank it up that much as I've got a set of washer sized Sentry III speakers with 15" woofers and my house starts to shake when the volume is up. So "most" of the time i'm at low level on the volume and thats where the real clarity shines thru. My new to me AU-D11 II dropped a right channel and this amp is beyond my limited scope to tackle so its out of play right now and I really miss it. The 719 is just not up to the same par sound quality wise. Some folks here thought the 719 was better or at least on par with the 717. Speakers I'm sure have a good deal to do with how one amp sounds hooked up to amp A vs amp B, as well as room acoustics etc.

My .02,

Bob Brown

 

[Zekeman]

I do not use a separate power amp per se. The amp in the D11 drives two JBL L96's. The preamp signal goes to an active crossover which filters out frequencies above 40Hz and sends the low frequencies to a B-2101 power amp...which drives passive subwoofers.

Makes for awesome audio quality!

 

[UpsideThe Head]

I do not use a separate power amp per se. The amp in the D11 drives two JBL L96's. The preamp signal goes to an active crossover which filters out frequencies above 40Hz and sends the low frequencies to a B-2101 power amp...which drives passive subwoofers.

Makes for awesome audio quality!

Oh, I get it.

 

[Bigerik]

I'm glad your happy with the AU-D11II. I am very lucky in that when I got
mine back from the Hi-Fi Hospital it was spot on perfect and has worked that
way ever since. All original parts, just a cleaning and adjustment. I have a
second one there now which I can't wait to get back as well.

Don't tell John I told you, but I hear yours is pretty close to being done....