Anaview AMS0100-2300 build

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I love my diy Mini Aleph Class A amp, but it's a bit brutal on the electricity bill, so have been meanin for quite some time to do a good Class D build. In the past I've only dabbled in Tripath 2020, which I liked alot but it was a bit underpowered (curiously my Mini Aleph, which is around 10wpc, never felt lacking).

After some hesitation between the Hypex ucd180/400hg hxr modules and other options (nCore a bit too expensive), I decided to go for the new Anaview AMS0100-2300 modules -- http://www.profusionplc.com/pro/gex/pcatdtl0?ipartno=AMS0100-2300 -- and get a pair to use in BTL mode.

They are being built into a Hammond 1550j case.
At the moment I'm testing them with balanced inputs, direct from a Teac UD-301 dac, attached to a PC running JRiver media centre.

The input impendence on these amps is low: 2.5k-12.5k SE, and 1.39k-12.5k balanced. The Teac DAC has an output impedence of 200ohms.

I'll also be incorporating input buffers -- have ordered a set of Per-Anders' Sjöström Super Buffer - I'll get those boards in a few weeks, so at some point will be able to test the Anaview with a good input buffer stage. These buffers have an Input impedance of 1M ohms, and an output impedance of 2.5 ohms. I've left plenty of space in the cases for the buffers+psu.

Tested the amps first without any input capacitors -- no pops or anything nasty. Then remembered I had a load of Black Gate NH 150uf 350v in my parts bin which I've used as coupling caps in the past and they seem to me to be totally transparent, so I've popped a couple in this build just for testing.

Have some crackling/distortion/static noise at high volume, though that could be because of the clip leads all over the place. Will solder them up next and see if that fixes it. Will comment on sound too once this issue is resolved.

Some pictures below.
 

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Wired/soldered up properly one of the amps now with the BG coupling caps, and still had crackling/distortion/static noise at high volume... however turns out this was because of the JRiver output settings, which was outputting everything to 2x DSD. Anyway turned this off and the amp is quiet as a mouse and very clean.
 

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Both wired up and working perfectly. Just leaving them playing and will reserve making any definitive subjective comments until I can get accustomed to them and then start doing some direct comparisons with the Aleph. All I can say at this point is that they sound really very good. The bass is amazing -- very tight and detailed, no flab at all. They seem to grip the speakers like nothing else. Detail is exceptional.

Still need to test more with/without input caps, and then, when I get the boards from P-A, with/without input buffers.

As for the modules themselves, they are super easy to work with -- very much plug and play and the diy work is chassis/connectors. The boards seem very high quality and well made. Given the efficiency of these amps, they'll be the 'always on' amps in the house.
 

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After a couple of days of listening, I can give some initial impressions based on listening comparisons between the Anaview and the amplifiers that I can actually do a comparison with. Obviously some people will be keen to know how the Anaview sounds compared to Hypex UcD or nCore... sorry, can't be of any help.

Compared to a Marantz PM17 (this is a push-pull, solid state, 60wpc integrated amplifier. Very well made, very reliable. About 16 years old). The sound of the Marantz can be described as warm, if not a bit muddy and mushy. Bass is a bit flabby. Fatiguing/harsh with full range speakers. Good with two-ways. Not a bad amp, but not a great amp either. In comparison the Anaview has significantly tighter bass, feels far more powerful, has more detail, and throws out a bigger soundstage. The difference in detail is incredible. Night and day. Hardly surprising though -- the Marantz is an integrated that has A LOT in the signal path. So this comparison was just for the sake of it.

Tripath 2020 (DIY board by autocostruire.com): The Tripath has some of that Class D detail but a bit of (reputedly) "tube warmth" (woollyness?) too. Sounds terrific with full range speakers with certain sources. On the downside it's also a bit dry, just doesn't have the muscle to drive 2-ways, and can be bit harsh on the highs too. Anaview has significantly better bass and control over 2-way speakers, and sounds similar to the Tripath with full range speakers, only far more detailed (and less forgiving of poor sources). The Anaview is better on the highs, no glare. The Anaview throws out a bigger soundstage.

Compared to Nelson Pass-design based Mini-Aleph amplifier (based on BrianGT's boards, with overbuilt PSU and quality components. About 10-15wpc. Class A). I love this amp. It's been my favourite for several years, but it's not really an "always on" amp because of the power consumption, even for this low-powered variation. It sounds great with full range and and 2-ways, has a very lush midrange and seems to make every source sound good. It works well with passive and active preamps. In fact to my ears this amp is just about perfect. At my listening volumes I've never found it under-powered.
In comparison the Anaview has more grip over the speakers, tighter and more detailed bass - the difference on this is very big. In the midange and highs, the Anaview is detailed and transparent where the Aleph is lush... The lows sound better on the Anaview, the mids are perhaps slightly pronounced on the Aleph. The highs are all there in all their glory (or not) on the Anaview, and smoother on the Aleph.


Some initial thoughts:
The Anaview modules have exceptional power and grip, incredible detail, incredible bass (I think this is their strongest point), and are certainly the most detailed/clear/neutral amps I've ever heard. Perfect for studio/mastering use.
Bear in mind I've been testing the Anaview amps with digital and analogue sources, with a passive pre. Given their low input impedence, they may benefit from an input buffer stage, which I will add at some point.
I like these Anaview modules. They've plenty of power and run cool, are very easy to build, and are stone quiet. I think for accuracy and detail, it would be hard to do any better -- although accuracy and detail do have their downsides. One thing I've learnt in DIY audio is that system synergy is a complex thing, as one is essentially dealing with any number of combinations. In the home environment, they can feel a bit unsubtle and overdetailed, and very unforgiving of poor sources. When playing compressed online radio streams, for example, you can hear all the compression artifacts in all their horror. Maybe a tube pre would deliver the best of both worlds?
 
Another update: I rewired the amps into single ended mode (with a toggle switch to changed between balanced and SE) and this means I can use a preamp in the chain. I have an Audio Note M-One preamp, which is a single-ended class A tube preamp, which I happened to get on ebay a while back at a great price.
With the Aleph I found this preamp was a bit "too much" -- it seemed to make things a bit mushy, so it was hardly used.
However with the Anaview it really adds everything good and nothing bad: the Class D bass and overall exceptional detail is still there, but the midrange is at least up to the level of the Aleph now.
Am very, very happy.
 
No, sorry, so far I've only tried them properly in BTL mode, with balanced and unbalanced inputs, with and without coupling capacitors in the signal path. When I had the modules on the bench for testing (to check they work OK) I wired them in stereo mode for a few minutes, but didn't do any critical listening.

I wanted to have a bit of headroom, and the specs show THD vs power (into 6Ω) in BTL mode is 0.003% at 50w and 0.01% at 100w. In stereo mode, THD vs power (into 8Ω) is 0.003% at 10w and 0.01% at 20w. I think for 250 euros, two modules wired up in BTL are terrific value. For a smaller amp for a smaller room, I wouldn't hesitate to get one of these modules and wire it up in stereo. Still terrific value I think.

Just to repeat what I've said earlier, these modules are shockingly accurate. With a passive pre they really show poor mastering on digital. I've been enjoying comparing different digital releases -- SACD, 24/192, 24/96, 16/44.1 rips -- and am convinced these modules would be fantastic in a studio mastering environment as there are things on recordings (good and bad) that I've just heard for the same time. But for me though they really come to life with my tube preamp -- I feel I'm getting the best of both worlds.
 
Thanks for info! Maybe I will try them in my active 4way system.
The output impedance of my eight channel Exasound e28 DAC is 200 Ohms. Do you think I will need caps? Have you listened with and without caps and heard a difference? I would like to connect DAC straight to the amp.
What do you mean by "best of both worlds"? Is Anaview too bright/harsh or you simply need some warmth to "mask" harshness of bad recordings etc.?
 
No problem!

1) The output impedence of my DAC is about 200 ohms, and it seems to match the Anaview modules without any problem -- although the input impedance of the amps is quite low (see the sepc sheet). The Anaview modules may or may not benefit from buffers at the input, and I'm waiting on some Diamond Buffer boards to build and install, at which point I'll update.

2) I'm using caps at the input of the Anaview modules because there are no caps on the output of my preamp, and there is a tiny bit of DC on its outputs which give the woofer a bit of a pop and a tiny bit of hum without caps. I've tried with and without caps -- the caps eliminate the pop and slight hum from my tube preamp without any noticable degradation on sound quality (to my ears at least). When connected directly to the DAC, the amps get no pop or hum without caps, and I also could not detect any loss of quality with them in, so I've just left them there. The caps I'm using are some old BG 150uf 350v I had around, which are overkill for the task. I also tried some Sonicap 22uf in the same position, and could not tell the difference. Whether or not you need caps on the input probably depends on the output of your DAC, which if well designed (it looks like it is) should probably be fine without.

3) I wouldn't say the Anaview is "bright" or "harsh" -- it seems to me to be very well balanced and extremely detailed. It's a double-edged sword: with great recordings it sounds terrific (and it sounds superb with vinyl), but on bad digital recordings it can show them up as such and as a consequece sound a little thin and flat. The tube preamp however seems to add a little midrange bloom and some extra body. It's a question of taste and source material I think.

I also think that with an 8 channel DAC and an active system, the opportunity for playing with DSP and room correction is enormous, and you should be able to find a formula that works well. I plan to experiment with that next. Hope that helps in some way!
 
Hi Ssmith,

Thank you very much for your comments/feedback regarding this very interesting Anaview power module. I think your findings pretty much agree with two comments about exactly the same setup, built by Finnish professional speaker manufacturer Amphion. They call it the AMP100.

In the following link, you can find some comments from an audiophile point of view:
6moons audioreviews: Amphion One18


In the next link, more comments and a comparison against the Ncore NC400 module, from a professional sound engineer:
https://www.gearslutz.com/board/high-end/851143-high-end-nearfield-test-87.html (read post No. 2591)

With the components you currently have on hand, you can create a very versatile setup:

1 - For good CD recordings, DSD, SACD, Vinyl, or for detail analysis:

TEAC DAC -> (XLR) -> Anaview Amps

2 - For a warmer, more forgiving sound, or bad recordings where you are ready to sacrifice some neutrality:

TEAC DAC -> (RCA) -> Audio Note preamp -> (RCA) -> Anaview Amps

So without changing a cable run, just moving a switch, you can get two types of experiences. This setup would please the "detail" hungry, as well as the "tone" hungry audiophile.

I´m currently using a pair of Anaview AMS1000-2600 power modules in BTL mode driven directly by a Benchmark DAC2 in balanced configuration. In the future I may be interested in adding a tube preamp or buffer, to gain some versatility and explore the tone possibilities beyond the current neutrality of the sound.

For such reason, I'm very interested in your tests with the new input buffers, as well as more feedback regarding the sound of your tube preamp (Output Impedance around 2 KOhm) directly connected to the amplifiers (Input Impedance from 1,3 to 13 KOhm).

BTW I think the matching between your TEAC DAC and the Anaview modules is already excellent. An input buffer will probably do nothing or may even subtract transparency to the signal. The only issue in this case MAY be the digital volume control, but it depends on the listening levels you normally use.

Thanks again!
Sebastian
 
Hi Julf,

I was also surprised by the comments regarding the NC400. Do you happen to own an NC400 based amplifier BTW?

However, I realize that specs are important but don't tell the whole story. Don't you agree?

For example, the NC400 has better specs than the little Anaview amplifier, but also better specs that its bigger sibling the NC1200 power module, or even than a Pass Labs XA-100.5 amplifier!!!

There's clearly much more going on in the design and performance of these amplifiers than their plain specifications.

Also, I think it is really difficult to measure real life performance. For example, a THD vs Power @ 6,65 Khz chart won' t tell you how the treble is distorted when at the same time there's a high power bass signal being amplified. Typical case of a low key piano note, with high pitch attack and deep bass.

I have a theory as why these Anaview modules sound so transparent and detailed. I can be wrong, but I think is related with the lack of an input stage or buffer.

The NC400, as a DIY friendly module, already includes a discrete input stage that allows the user to match the amplifier with all kind of preamps, with a wide range of output impedances, or even passive volume control circuits.

As good as this discrete input stage is, and like every electronic circuit, it also introduces distortion. There's always a trade off, no free lunch here.

In fact, the NC400 THD specifications are probably measured without considering the input stage, only the power module, same as the NC1200 specs that probably don't consider the IC input stage (which is easily removed to allow OEMs to build their own front end circuitry).

By not including an input stage, the Anaview amplifiers seem to be more OEM oriented. This fact presents a challenge and an opportunity to the DIYer. On one hand, improper impedance matching with the preamp can lead to channel imbalance and premature LF rolloff. On the other, using the right preamp can lead to the highest level of detail and transparency.

This might explain the reviews and comparisons mentioned in my previous post.
 
I was also surprised by the comments regarding the NC400. Do you happen to own an NC400 based amplifier BTW?

Yes.

However, I realize that specs are important but don't tell the whole story. Don't you agree?
Depends on the specs.

For example, the NC400 has better specs than the little Anaview amplifier, but also better specs that its bigger sibling the NC1200 power module, or even than a Pass Labs XA-100.5 amplifier!!!
Yes. I think all 3 are better than our ears and our speakers.

Also, I think it is really difficult to measure real life performance. For example, a THD vs Power @ 6,65 Khz chart won' t tell you how the treble is distorted when at the same time there's a high power bass signal being amplified. Typical case of a low key piano note, with high pitch attack and deep bass.
The frequency of the high power signal won't matter - it is the power, not the frequency, that is important. If you have additional HF distortion when the amp is heavily loaded, it won't matter if the load is at 50 Hz or 5000 Hz. Thus measuring the THD at 6.65 KHz at full power tells you what happens to the treble when there is a simultaneous high power signal.

I have a theory as why these Anaview modules sound so transparent and detailed. I can be wrong, but I think is related with the lack of an input stage or buffer.
The input stage is the equivalent of one preamp stage. Are you saying that using a preamp lets down current class D power amps?

In fact, the NC400 THD specifications are probably measured without considering the input stage, only the power module
As far as I know the nc400 measurements are for the complete module, including the input stage.
 
Looking at those links, I can understand that the Anaview may be preferred over the nc400 in certain applications -- in particular studio/mastering and nearfield listening. Certainly the absence of a buffer stage may provide added transparency (I'm guessing here), the power is more than adequate for nearfield, and the low impedance input is a non-issue with many modern DACs. Plus the modules are significantly cheaper, with the PSU built in -- not a trivial consideration for a manufacturer.

The absence of a buffer has its pro and cons. In some systems it may not need one, providing the resulting blindingly-accurate sound meets the taste of the listener. In my situation, running it direct from the DAC, there's nothing wrong with the sound but it's just not quite my taste -- although I will revisit this configuration once the system has settled in and may change my mind.

But when dealing with certain preamps/long cable runs, it may benefit from a buffer, providing for added build complexity.
Even then, the absence of a buffer also provides for some flexibility -- the builder can go for transparency (I'll be trying a diamond buffer -- and will then experiment with various preamps) or tone (why not insert a tube input stage?).
 
For such reason, I'm very interested in your tests with the new input buffers, as well as more feedback regarding the sound of your tube preamp (Output Impedance around 2 KOhm) directly connected to the amplifiers (Input Impedance from 1,3 to 13 KOhm).

Hi Sebastian,
Many thanks for your comments!
At the moment, with the tube preamp directly feeding the unbuffered inputs of the Anaview in SE, my ears do not notice any issues and the sound I'm getting is very pleasing.
However I'm looking forward to the test with the diamond buffers -- I have all the parts and am just waiting on the boards from Per-Anders (they were out of stock). Assuming my SMD soldering goes without a hitch ;) they will hopefully be installed in 3-4 weeks from now.
One major pleasure I'm getting with these amps is just having them on all day and not worrying about the bill!!!
all best, ssmith
 
Yes. I think all 3 are better than our ears and our speakers.
We can think that within their spec limits, all 4 (including the Anaview) are better than our ears and our speakers.
The input stage is the equivalent of one preamp stage. Are you saying that using a preamp lets down current class D power amps?
No. As you said, the input stage is similar to one preamp stage, and main purpose is to adapt impedances. So, if you already have a good matching preamp and the interconnects are not long, why add another stage to the chain? I tend to think that in this case, less is more.
As far as I know the nc400 measurements are for the complete module, including the input stage.
It is not clearly specified in the NC400 datasheet.
 
At the moment, with the tube preamp directly feeding the unbuffered inputs of the Anaview in SE, my ears do not notice any issues and the sound I'm getting is very pleasing.

Thanks for the feedback ssmith! This is great news! You are already getting excellent results, even without having the best impedance matching. This encourages me (and probably other Anaview power module owners), to try tube preamps directly connected to the modules.
One potential issue that has not been addressed yet with this modules, is the same tube preamp directly connected to the module, but the later configured in 2 CH mode, where the input impedance is not only low, but asymmetric between channels.
Rgds,
Sebastian
 
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