[outsider10]

These two amp setups are on my short list. Has anyone compared them directly?

Leaning toward the AVA 400. The PS Audio monos look like a nice option, but prob don't need that much power, and a single box solution is preferable.

Will be used with a refurbished Yamaha C4 pre-amp for now, but eventually want to move to a tube-based pre.

My speakers are Polk LSiM 705s, rated to 250wpc. Sources are Marantz TT15 turntable and FLAC > Schitt MODI 3 DAC. (Mostly vinyl.) I don't necessarily listen at high volumes very much, but system is set up in a largish "great" room.

Music preferences are mainly acoustic, jazz, and "world". But still spin some classic rock on occasion when I'm home alone like Ferris Bueller..

Thanks in advance..

[WGH]

So far I have had no luck convincing Frank Alles, a senior editor for Stereo Times to lug the 83 lb, $7,499, PS Audio BHK Signature Stereo 250 Power Amplifier (review) over to my house, no matter how much fun I tell him it will be. But I have heard the PS Audio amp at his house driving Legacy speakers, it is nice and I would like to have one just because. But truth be told the heavens didn't open up like those $60,000 amps I heard at RMAF so I'm hanging onto my AVA Vision SET 400. PS Audio has a house sound so the M700 would sound similar but I am not a fan of Class D, no matter how well implemented so I would pass on the M700.

Another reason to pick the SET 400 is that paired with the AVA Fet Valve CFR preamp (it's got 4 tubes!) the sound is wonderful and there is no concern about system synergy. I suggest taking the money you would have spent on the M700's and put it towards a pair of Zenwave D3 interconnect cables between the preamp and the amp. You will get a nice solid center image and wide soundstage, the speakers disappear. You are just going to have to trust me.

[CSI]

These two amp setups are on my short list. Has anyone compared them directly?

Leaning toward the AVA 400. The PS Audio monos look like a nice option, but prob don't need that much power, and a single box solution is preferable.

Will be used with a refurbished Yamaha C4 pre-amp for now, but eventually want to move to a tube-based pre.

My speakers are Polk LSiM 705s, rated to 250wpc. Sources are Marantz TT15 turntable and FLAC > Schitt MODI 3 DAC. (Mostly vinyl.) I don't necessarily listen at high volumes very much, but system is set up in a largish "great" room.

Music preferences are mainly acoustic, jazz, and "world". But still spin some classic rock on occasion when I'm home alone like Ferris Bueller..

Thanks in advance..

I have lived with and enjoyed my M700's for six months. I would not give them up for anything else. I have owned a number of amps over the years, some tube, some SS class A and also class A/B. The only thing that came close in musical satisfaction was my First Watt F7 (class A). If you are inclined toward Frank's amp, go for it. It is a great one.  If you audition M700's you will likely hear an improvement in bass (depth, control, the whole nine yards). But otherwise not too much difference IMO. The PS amps only draw 23 watts at idle so you can leave them on 24/7 if that is important to you. Otherwise Frank's amp should be eminently satisfying. Enjoy the music.

[outsider10]

Thank you for the replies folks.

Although they do sort of point me in two different directions.

It seems the M700s can be had for a price similar to the SET 400, and that both are generally well regarded.

Being kind of old-school, and generally a "late-adopter" I'm still leaning toward the SET 400. Seems to represent up to date implementation of proven A/B technology.

But the M700s do seem to represent several years of experience with implementing Class D.

[WGH]

Another idea comes to mind:

CSI mentioned an improvement in bass, it may be small incremental increase since the Polk LSiM 705's only go down to 42 Hz. You can only squeeze so much out of the two 5"x7" subwoofer drivers and the powerport. The price difference could be put toward a Rythmik Audio L12 Direct Servo Subwoofer
http://www.rythmikaudio.com/L12.html

Now that would really give you an increase in not only bass but space, depth, increased low level detail and upper midrange clarity enabling you to hear into the music.

The AVA pre-amp has a low level filter if the turntable puts out too much 20 Hz rumble, it's amazing what you find out with a good sub. 

[EkW]

I almost went for an AVA amp (DVA 600s) but for mysterious reasons possibly related to the April 20% discount and generous trade in got the new PS Audio M1200s. Lots of folks traded in their M700s for the M1200s. Haven't heard any of those folks regretting it. All say that it is a big improvement. The AVAs are really nice sounding and a sub or two really help as WGH says.
Between the AVA and the M700s I would go with the AVAs. The m700s are using older generation class d modules. The new ones are much better.

[maty]

I have commented this several times already. I am still waiting for a reply to the email I sent to PS Audio.

They screwed up the IcePower 700ASC class D module's specs with its own buffer. From having no harmonics to being dominant H3.

Forget PS Audio M700.

https://www.stereophile.com/content/ps-audio-stellar-m700-monoblock-power-amplifier-measurements

[maty]

If you want class D amps, better others.

[RDavidson]

They did it intentionally to "flavor" the sound, maty. They've openly said this was the point of the buffer. This is probably why they never responded to you. They're not hiding anything. With the addition of the buffer, their amps will sound unique in comparison to amplifiers using just the off-the-shelf ICE modules. Also, we all know that measurements do not tell the whole story regarding how any amplifier will sound. One has to listen and judge if the measured distortions are good or bad to their ears. If you don't like what PS Audio has done, just go buy one of the many other options on the market that simply use the off-the-shelf parts. I'm not sure what your point is.

[maty]

You can "flavour" the amp with dominant H2, the question is how much H2, -73 dB? Never intentionally dominant H3.

[outsider10]

I think I'll watch & learn about evolution of Class D from the sidelines..

In the meantime, just ordered a SET 400.

[maty]

My speakers are Polk LSiM 705s, rated to 250wpc. Sources are Marantz TT15 turntable and FLAC > Schitt MODI 3 DAC. (Mostly vinyl.) I don't necessarily listen at high volumes very much, but system is set up in a largish "great" room...

https://www.amazon.com/Polk-Audio-LSiM-705-Floorstanding/dp/B0067XUYEQ

[ Total Frequency Response    20Hz - 40kHz
Upper -3dB Limit    30kHz
Lower -3dB Limit    38Hz
Nominal Impedance    8 ohms
Efficiency    88 dB
Recommended Amplifier Power    20 - 300 Watts per channel
Inputs    Dual gold-plated binding posts
Crossover    Orth crossover design
Tweeter/midrange
crossover frequency    3kHz
Midrange/midbass
crossover frequency    300Hz
Midbass/woofer
crossover frequency    100Hz ]

Maybe you can save money:

AVA Set 120 Control Amplifier
https://avahifi.com/collections/solid-state-power-amplifiers/products/set-120-control-amplifier

[ Our new SET Control Amplifier runs Class A/B, and is biased as Class A at normal listening levels. It puts out 60 watts per channel into 8 ohms and much more into 4 ohm loads. The SET name stands for its unique Single Ended Transistor voltage amplifier design.  This is our newest design with a simple but amazingly effective bipolar transistor front end followed by a very fast and rugged power mos-fet current amplifier section.  Bandwidth is flat from 3Hz to 70KHz. For use with its passive control section, the gain of the power amplifier sections are set 6dB higher than in the separate SET 120 power amp.

Our new SET amplifiers are uniquely DC stable. This means they will not generate speaker damaging DC drift even when driven past clipping. ]

if I were you I would ask first to Frank!

[RDavidson]

You can "flavour" the amp with dominant H2, the question is how much H2, -73 dB? Never intentionally dominant H3.

That's true. Odd order harmonics are usually not pleasing to our ears. What's important is the magnitude of H2 or H3 relative to THD and at what frequencies is it prevalent, right? Our ears are more sensitive to some frequencies than others. Reviewers have commented that the M700's have a very clean, neutral, and smooth sound with a hint of warmth. This would suggest that the H3 present in the measurements doesn't tell the whole story regarding the amp's subjective performance. Always 2 sides to every coin.

Regardless, I think the original poster can't really go wrong with either AVA nor PSA. Both companies are proven experts in their fields. I highly suggest trying to get both amps in house and giving them a try. On a side note the PSA S300 is no slouch whatsoever. If you want similar performance to the M700's but don't need the power nor want 2 boxes, give the S300 a try. It is a rather unsung hero of an amp as the focus is on its larger siblings. Something else to note, it has been said many times that the balanced input on ICE amps and other class D amps is better than the single ended inputs. If you're running a balanced system or plan to, this is another consideration. Hope this helps.

[maty]

About harmonics, days ago:

BLIND TEST RESULTS Part II: "Is high Harmonic Distortion in music audible?" Respondent Results
http://archimago.blogspot.com/2020/06/blind-test-results-part-ii-is-high.html


Months ago:

Beta Test: DISTORT - audibility of distortions
https://www.audiosciencereview.com/forum/index.php?threads/beta-test-distort-audibility-of-distortions.10163/

[outsider10]

Maybe you can save money...AVA Set 120 Control Amplifier...
if I were you I would ask first to Frank!

I think the SET 120 would be at least adequate and probably sound pretty nice. That being said, I've been influenced by the many people who indicate that more power, especially with bigger speakers that are rated for it, provides significant sonic benefits beyond just the ability to play at higher volumes. Also, my system is set up in a large room.

Also, I don't swap out gear very often, and wanted to have the flexibility of a beefier amp. I got a nice price from Frank on a returned 400, guaranteed "as new" with full warranty..

..On a side note the PSA S300 is no slouch whatsoever. If you want similar performance to the M700's but don't need the power nor want 2 boxes, give the S300 a try. It is a rather unsung hero of an amp as the focus is on its larger siblings. Something else to note, it has been said many times that the balanced input on ICE amps and other class D amps is better than the single ended inputs. If you're running a balanced system or plan to, this is another consideration. Hope this helps.

I was looking at the S300 too. I posted here after seeing 2nd hand set of S700s for sale at a price similar to the SET 400.

I don't have a lot of experience hearing different quality amplifiers/systems, don't really have opportunities to audition, and rarely get anything new. As noted above, either an AVA or PSA amp would probably sound nice to my ears and serve me well.

I went with AVA based on somewhat more "mature" technology, nice price and great reviews suggesting a sonic signature that I'd like.

[maty]

The ideal is to know the characteristics of the loudspeaker well to know what power we need, depending on the distance to the listening point and the type of recordings we listen to (dynamic range).

You have to do calculations, with a margin of safety.

[maty]

AVA SET 400 is only a poweramp. You have a cheap DAC without volume. Preamp? New DAC+volume? -> money money

[RDavidson]

The ideal is to know the characteristics of the loudspeaker well to know what power we need, depending on the distance to the listening point and the type of recordings we listen to (dynamic range).

You have to do calculations, with a margin of safety.

Agree 100%. Understanding one's power needs based on those criteria are the most important. In addition to listening distance, the size of the listening room also plays a factor. If you sit close to the speakers, even in a large room, you may not really need a lot of power.

Outsider10, I used to think more power is better too...but getting the best performance for your personal needs is a much more complex issue. I find that smaller, simpler, amplifiers often perform better (sound better) than larger, more complex, more powerful amplifiers in the same system. I understand the idea of getting the biggest amp you can afford and hope it sounds good, but this really isn't a very comprehensive approach. While I don't think you can really go wrong with your choices here, you could go more right.

[opnly bafld]

Outsider10, I used to think more power is better too...but getting the best performance for your personal needs is a much more complex issue. I find that smaller, simpler, amplifiers often perform better (sound better) than larger, more complex, more powerful amplifiers in the same system. I understand the idea of getting the biggest amp you can afford and hope it sounds good, but this really isn't a very comprehensive approach. While I don't think you can really go wrong with your choices here, you could go more right.

 

[outsider10]

AVA SET 400 is only a poweramp. You have a cheap DAC without volume. Preamp? New DAC+volume? -> money money

From my post above: "Will be used with a refurbished Yamaha C4 pre-amp for now, but eventually want to move to a tube-based pre...Sources are Marantz TT15 turntable and FLAC > Schitt MODI 3 DAC. (Mostly vinyl.) I don't necessarily listen at high volumes very much, but system is set up in a largish 'great' room."

I do understand that the Modi is pretty much a bottom of the line DAC. It'll get upgraded at some point. As you note, "money money"...

...In addition to listening distance, the size of the listening room also plays a factor. If you sit close to the speakers, even in a large room, you may not really need a lot of power....I used to think more power is better too...but getting the best performance for your personal needs is a much more complex issue. I find that smaller, simpler, amplifiers often perform better (sound better) than larger, more complex, more powerful amplifiers in the same system. I understand the idea of getting the biggest amp you can afford and hope it sounds good, but this really isn't a very comprehensive approach. While I don't think you can really go wrong with your choices here, you could go more right.

I agree in principle. For about the same cost, I could have gotten the 2nd hand 350wpc PSA S700s, but instead chose the 225wpc AVA. So I think I did take into account the potential tradeoff between sheer power and actual sound quality.

It's true I'm "hoping" it sounds good, but I'd argue there's ample evidence that it will, i.e. numerous reviews saying as much, indicating a sonic character that fits what I'm looking for, and none suggesting it's a particularly finicky or system-dependent amp. There are also reviews suggesting that my particular speakers (even though they are "just Polks") respond well to more and higher quality power.

To be sure, I'll have to see how things work out in MY situation. Regarding that, I rarely sit very close to my system. I'm usually up doing other stuff, e.g. cooking dinner at the other end of the room. In fact, I'm embarrassed to admit how little focused listening I actually do. You could argue, and my wife (aka the Chief) does argue) that my entire system is overkill for the amount of opportunities I have for focused listening. But I'll be retiring in a couple years, so hopefully that will change..

I usually upgrade components opportunistically when a great deal comes along. I got my hand forced with amplification now, because my restored vintage Sansui (130wpc) gave up the ghost unexpectedly and rather than fix it again, decided to try to a more "modern" amp. Partly for reliability reasons, and partly because I surmised that newer gear from well-regarded builders stands a good chance of sounding better.

With a busy professional wife and 12 yr-old daughter, a job, and other interests and hobbies in addition to audio, I don't have a ton of time or opportunities to try out different gear. So I based my choice on the best research I could do in a reasonable amount of time, i.e. familiarizing myself with some what's available in my price range, discussions RE Class D and more traditional designs, monitoring audiogon, sifting the archives here, etc. While the SET 400 might not be the optimal choice I don't think its a bad one.