Solid State Power Amp Reviews

Dan D'Agostino Progression Mono monoblock power amplifier Page 2

Returning to Morlot and Seattle's Rite, I confirmed that while the sound was a touch warmer than neutral higher in the range, timbres were absolutely believable with timpani and bass drum. Further listens to recordings of percussion, cello, and double bass confirmed that, through my Wilson Audio Alexias, the Progressions excelled at conveying low pitches with more tonal accuracy than I was accustomed to.

I also began to realize that while my reference Pass Labs XA 200.8 monoblocks sound gorgeous, and convey a special glow around the edges of each note, the Progressions illuminated each note from within. The experiences are different but equally gratifying.

I've often lamented that my audio reviews have never approached the levels of poetry and flights of fancy that make Herb Reichert's writing so special. But as I continued to explore familiar and new recordings, I discovered that the Progressions made me want to listen deeper and deeper, and play entire compositions without pausing to take notes. I was seduced without knowing it—and when my head cleared, I imagined the fabled Sirens, who beckoned sailors to their deaths, luring me with their spell. Herb may be able to paint a better verbal picture of what I experienced—he's a visual artist, after all—but the call of the Progressions was so strong that, on multiple occasions, hours of listening went by without my remembering to use the pen I held in my hand.

A great amp will do that to you.

1017dagprog.2.jpg

Somewhere in my journey—when you've fallen in love, it's hard to remember such practical considerations as numbering the pages of whatever notes you do manage to take—I played "Insensatez," from Rosa Passos and Ron Carter's Entre Amigos (CD, Chesky JD247). In short order, I realized that I could hear guitarist Lula Galvão's fingering and the pitches of Carter's double bass as never before. Rather than sounding etched—the Progressions never sounded detailed to the point of being clinical—the D'Agostino's revelations of additional detail only brought the music closer to me. Ditto with "Black on White Paper" and "This Screaming Dream," from Zen Widow's Screaming in Daytime (Makes Men Forget) (CD, pfMentum PFMCD 069): I could hear slight, previously masked noises and ticks in the right channel as percussionist Garth Powell and his fellow musicians picked up and moved instruments. This CD was recorded on two-track analog tape by Joe Harley, and mastered by Bernie Grundman—the depth, width, and height of its soundstage blew me away.

As weeks went by, reviewing recordings for Stereophile.com became more of a joy than ever. Through the Progressions, Yo-Yo Ma, Chris Thile, and Edgar Meyer's recording of various works by J.S. Bach arranged for mandolin, cello, and double bass (24/96 WAV, Nonesuch 558933/HDtracks) revealed all its glories and shortcomings; while the sense of space in Rímur, the flawless pairing of Trio Mediaeval and trumpeter Arne Henriksen (24/96 download, ECM New Series 2520), positively tranced me out. I was also amazed that while David Chesky's download-only hi-rez recording of his song cycle The Spanish Poems, with soprano Maureen McKay and the Orchestra of the 21st Century (Chesky/HDtracks) was limited to 24/48—his usual DAC was being repaired—its spacious soundstage and color-rich palette suggested something of far higher resolution.

One of my most joyous listening sessions was with a new friend, a viola da gamba player, who'd recently moved to Port Townsend and attended a potluck we hosted. When he asked to hear Jordi Savall and his ensembles' M. A. Charpentier à la Chapelle Royale de Versailles (SACD/CD, Alia Vox AV DVD 9905), we sat stunned by the melding of beautiful voices with early instruments. Wishing my guest to hear more of how well the Progressions did with voices, I turned to Puccini's "Che gelida manina," from Franco Corelli's The Unknown Recordings (CD, EMI 5626992), and Verdi's "D'Amor sull'ali Rosee," from L'art de Montserrat Caballé, Vol.2 (CD, Forlane UCD 10905). When tenor Corelli opened up on his glorious high C, and incomparable soprano Caballé transitioned from mere threads of sound to full-throated outpourings, the dynamic contrasts were something to behold—even within the Compact Disc's limited dynamic range.

My final extended listen to the Progressions was with members of the Pacific Northwest Audio Society. We didn't compare amps, DACs, or anything else—we just enjoyed what the Progressions could offer. For much of the afternoon, I found myself turning off the lights so that, with the room illumined only by indirect light coming from a hallway window, we could sink even deeper into the music.

1017dagprog.3.jpg

Some of our selections included tracks from Yello's Toy (24/48, Polydor) and streams of music by trumpeter Arturo Sandoval (16/44.1, Tidal HiFi). While both were flawlessly delivered—the Progressions controlled the pounding low end of Yello's "Electrified II" without sweat while throwing a huge soundstage—the most startling track of all was one I've played countless times: soprano Maria Callas singing the Sleepwalking scene from Verdi's Macbeth, recorded in 1958 for her album Callas Portrays Verdi Heroines, with Nicola Rescigno conducting the Philharmonia Orchestra (24/96 file, Warner Classics). Not only could I hear more details of Callas's vocal production than ever before, but I also discovered that solo instruments in the orchestra were surrounded by what sounded like unprecedented amounts of air. That the flute stood out so hauntingly, as if singing in the dark, confirmed that Verdi and Rescigno intended every sound of the orchestra to underscore Lady Macbeth's bloodthirsty madness. To use a descriptor favored by John Atkinson, I was gobsmacked.

Conclusions
As I write these words, the Progressions sit boxed up, awaiting shipment to JA's house. With the first few reviews I wrote for Stereophile, each such farewell was accompanied by the gnawing fear that John's measurements would lead him to write, "These are some of the worst-measuring amps ever to cross my threshold," and reveal me as a total dolt (footnote 2). I harbor no such fears about the Dan D'Agostino Master Audio Systems Progression Mono. Instead, I'm eager to discover if JA's tests will help explain how these monoblocks produced such detailed, natural-sounding, air-filled, ultra-dynamic, supremely musical sound.

While the Progression wasn't the most neutral-sounding amp on the planet, its mild warmth in no way interfered with its ability to communicate the visceral, emotional, and spiritual imports of music. Delicate music sounded exactly that, while ultra-aggressive percussion, screaming horns, and cries of pain—imagine some diabolical cross between Shostakovich, Diamanda Galas, and Metallica—only gained in impact from the Progressions' ability to reveal it in all its glory. "Wow!" only begins to tell the tale.


Footnote 2: Stereophile's reviewers don't see the measurements of the product they have reviewed until after they have written and submitted their text.—John Atkinson
COMPANY INFO
Dan D'Agostino Master Audio Systems
PO Box 89, 7171 E. Cave Creek Road, Unit K
Carefree, AZ 85377
(480) 575-3069
www.dandagostino.com
ARTICLE CONTENTS

COMMENTS
georgehifi's picture
Submitted by georgehifi on September 28, 2017 - 5:47pm

Agostino Progression Mono monoblock:
"Consequently, the Progression's reproduction of a 10kHz squarewave (fig.2) featured very short risetimes with, commendably, no overshoot or ringing apparent."

Linear Tube Audio ZOTL40 Mk.II power amplifier:
Read more at https://www.stereophile.com/content/linear-tube-audio-zotl40-mkii-power-amplifier-measurements#dF5kOX8x0c8mEESx.99
"the response extended very high, not reaching –3dB until 120kHz, this correlating with the superbly defined shape of a 10kHz squarewave into this load (fig.2). A slight amount of overshoot is visible in this graph, though there is no ringing."

These are great to see, and it's great that from the comments they're appreciated by the measurement team and readers alike.

Though when Class-D amps are measured, they normally have horrendous looking square waves, but these days Stereophile use low power special bench test filters to filter them so they look good to the readers. This is not representative of what's being sent to the speaker in normal everyday use.
This is from the days when Stereophile didn't use the "special" filters, to show what's really coming out the speaker terminals. I believe it should go back to this.
https://www.stereophile.com/images/archivesart/805CIAfig2.jpg

Cheers George

a.wayne's picture
Submitted by a.wayne on September 28, 2017 - 6:58pm

John, NPR ! not surprised all that RF hash did you in ... :)

Ortofan's picture
Submitted by Ortofan on September 29, 2017 - 1:10am

... "musical"? Is it the non-flat frequency response into a typical loudspeaker load? Is it the series of distortion products that are up to 20dB above the noise floor of a CD, let alone that of a higher bit-rate recording?

Why not perform a Hafler type straight wire differential test test on every amp that comes in for review?
https://www.stereophile.com/content/manufacturers-comment-0

Or a level-matched A/B comparison as demonstrated by Harbeth's Alan Shaw: https://vimeo.com/137001237

Perhaps a direct comparison with the Rotel RB-1590?
http://www.bwgroup.ch/wp-content/uploads/2016/11/Hi-Fi-News-11-2015-Test-Rotel-RC-1590-RB-1590.pdf

John Atkinson's picture
Submitted by John Atkinson on September 30, 2017 - 8:27am
Ortofan wrote:
Why not perform . . . a level-matched A/B comparison as demonstrated by Harbeth's Alan Shaw: https://vimeo.com/137001237

See my fairly recent writing on such tests at www.stereophile.com/content/simple-everything-appears-simple.

John Atkinson
Editor, Stereophile

Ortofan's picture
Submitted by Ortofan on September 30, 2017 - 3:44pm

... exceedingly straightforward.
Match the input sensitivity of the two amps being compared using a test tone and a voltmeter; find the clipping point of the lower powered amp (and then keep the input volume for both amps below that level); then switch back-and-forth between amps at will.
Is there something he's missing?

Have you considered acquiring one of the Audio by Van Alstine ABX Comparator units and having the Stereophile reviewers give it a try?
https://www.dagogo.com/audio-by-van-alstine-abx-comparator-review-part-1-audio-store-wiring/
https://www.dagogo.com/audio-by-van-alstine-abx-comparator-review-part-2-trials/
https://www.dagogo.com/audio-by-van-alstine-abx-comparator-review-part-3-new-twists-conclusion/

John Atkinson's picture
Submitted by John Atkinson on October 1, 2017 - 7:39am
Ortofan wrote:
Mr. Shaw makes the comparison testing seem exceedingly straightforward. Match the input sensitivity of the two amps being compared using a test tone and a voltmeter; find the clipping point of the lower powered amp (and then keep the input volume for both amps below that level); then switch back-and-forth between amps at will. Is there something he's missing?

Yes, such testing tend to produce false negatives, ie, not detecting a difference when one actually exists. So unless you want to "prove" that no differences exist, they are no more useful than sighted listening. I do admit, however, that the latter tend to produce false positives.

Ortofan wrote:
Have you considered acquiring one of the Audio by Van Alstine ABX Comparator units and having the Stereophile reviewers give it a try?

I tried out the original ABX box 30 years ago and found, for example, that I could identify absolute polarity with statistical significant certainty. I have also identified amplifier differences under blind conditions, even differences between series capacitors of different types. Yet those results were all dismissed by the proponents of blind testing. So what would be the point in repeating all that work? No-one would be convinced by the results, on both sides of the debate.

John Atkinson
Editor, Stereophile

Ortofan's picture
Submitted by Ortofan on October 1, 2017 - 3:45pm

... determined to be statistically significant, then on what basis were they dismissed?

Would no one at all be convinced by the results of blind/level-matched comparisons? There are probably those readers who pay no heed to the test measurements you publish, yet you expend the time and effort to make them. Results of an AB(X) test would provide additional input to the evaluation/decision process for those who might place some value on the outcome.

Lastly, Harbeth's Mr. Shaw has a standing offer of a free pair of his speakers to anyone who can distinguish between two amplifiers in a blind/level-matched comparison. Have either you or one of the reviewers on your staff considered taking him up on his challenge?

John Atkinson's picture
Submitted by John Atkinson on October 2, 2017 - 4:51am
Ortofan wrote:
If the results of your ABX comparison trials were determined to be statistically significant, then on what basis were they dismissed?

Because the results were contrary to what so-called "objectivists" believed. Demands for reviewers to participate in blind testing come from those who want such tests to "prove" there are no audible differences.

Ortofan wrote:
Results of an AB(X) test would provide additional input to the evaluation/decision process for those who might place some value on the outcome.

Did you not read the article linked in an earlier posting of mine? Performing a blind test that produces legitimate results when there are small but real audible differences is not a simple matter. And if no-one takes any notice of the results if they conflict with their beliefs, what would be the point?

BTW, my opinion is formed by having taken part in more than 100 such tests as organizer, proctor, and test subject since my first in 1977. I think it fair, therefore, to ask how many tests you have taken part in to be so sure of their efficacy?

Ortofan wrote:
Lastly, Harbeth's Mr. Shaw has a standing offer of a free pair of his speakers to anyone who can distinguish between two amplifiers in a blind/level-matched comparison. Have either you or one of the reviewers on your staff considered taking him up on his challenge?

I don't see any benefit in participating in Mr. Shaw's marketing.

John Atkinson
Editor, Stereophile

John Atkinson's picture
Submitted by John Atkinson on October 2, 2017 - 9:50am
John Atkinson wrote:
Ortofan wrote:
If the results of your ABX comparison trials were determined to be statistically significant, then on what basis were they dismissed?

Because the results were contrary to what so-called "objectivists" believed. Demands for reviewers to participate in blind testing come from those who want such tests to "prove" there are no audible differences.

For more on this denial of facts by believers in "scientism," see this essay I wrote 23 years ago: www.stereophile.com/asweseeit/894awsi/index.html.

John Atkinson
Editor, Stereophile

Ortofan's picture
Submitted by Ortofan on October 3, 2017 - 3:41pm

... I've been involved with approximately one blind/masked test per year - though never with consumer grade audio equipment. Whether the outcome is as expected or not, the methodology has proven useful as a means to preclude certain factors from influencing the results of a comparison test. If you doubt the validity of such a testing protocol, by what other means might you suggest eliminating such factors as unmatched levels, knowledge of the brand identity and product appearance from potentially influencing the outcome of a comparison test?

John Atkinson's picture
Submitted by John Atkinson on October 4, 2017 - 8:12am
Ortofan wrote:
On average, during the past four decades I've been involved with approximately one blind/masked test per year - though never with consumer grade audio equipment.

Thank you. My experience of those who demand blind tests of reviewers is that they have never taken part in such tests so have an uncritical belief in the results of such tests. You are a rare exception.

Ortofan wrote:
Whether the outcome is as expected or not, the methodology has proven useful as a means to preclude certain factors from influencing the results of a comparison test.

Of course. But without additional testing you have no idea if your blind test protocol is sufficiently sensitive to detect small but real differences. If, for example, your test cannot detect something that is known to be audible, such as a 1dB difference in level, then any results it produces will be meaningless. There must have been interfering variables that you have not accounted for. One such is even the fact that the listener's mental state in a test is different from what it is in conventional listening. I mentioned this in the articles of mine that I have linked in earlier responses, which I assume you have read. If you have not, then please do so.

Ortofan wrote:
If you doubt the validity of such a testing protocol, by what other means might you suggest eliminating such factors as unmatched levels, knowledge of the brand identity and product appearance from potentially influencing the outcome of a comparison test?

Level matching is trivially easy. Knowledge of the brand is not that important for professional reviewers because they audition so many products over so many years that they don't have a horse in the race. If you doubt that, then I have to ask why you subscribe to Stereophile at all?

John Atkinson
Editor, Stereophile

Ortofan's picture
Submitted by Ortofan on October 5, 2017 - 12:04am

... is a key gating factor in the process of developing a new product and the decision of whether or not to release it to production. If the test panel determines that the new product is in some manner better/preferable to (or at least discernibly different from) an existing one, then the product is more likely to get approved for production. If the test panel cannot make a statistically significant distinction, then its future might hinge on whether or not it can be made more reliable or brought to market at a lower cost than the competition.

Also, certain individuals are more or less amenable to participating in blind/masked comparison testing, so you use multiple subjects. Likewise, their mental state can vary from day to day, so you conduct multiple trials.

Agreed that level matching (of electronics at least) is a simple process - but do your reviewers always (or ever) do it? With digital disc players and DACs it's not uncommon for the output from a 0dBFS input to exceed a nominal 2.0V level.

Continued interest in Stereophile is because you still conduct and publish the results of objective tests. For example, I'd prefer to spend $3K (or $6K for a bridged pair) for an amp that measures like the Benchmark AHB-2 rather than an order of magnitude more for this particular one, whose measurements, IMO, leave significant room for improvement.

mauidj's picture
Submitted by mauidj on September 29, 2017 - 4:27pm

when I read stuff like this...

"I also began to realize that while my reference Pass Labs XA 200.8 monoblocks sound gorgeous, and convey a special glow around the edges of each note, the Progressions illuminated each note from within."

Is it just me?

JoeinNC's picture
Submitted by JoeinNC on September 29, 2017 - 7:51pm

No, it’s not just you.

supamark's picture
Submitted by supamark on September 30, 2017 - 10:06am

he has synesthesia. I do, and sounds have palpable textures to me with some visual as well. For example, in a nice live hall, reverb tends to have an enveloping syrupy quality to me (denser reverb, thicker syrup) with a bit of visual glow (color and intensity dependant on how bright and dense respectively the reverb is).

Maybe you're simply mocking what you don't understand, and that's really not a good look.

tonykaz's picture
Submitted by tonykaz on September 30, 2017 - 2:22pm

The Electro stuff was gorgeous sounding, I don't know why, I'm an engineer, my partner was an engineer.

But that Electrocompaniet could make our big Thiel CS3 play beautifully, much more beautifully than any other gear we ever got our hands on.
We couldn't get the Krell stuff but I had access to the Krell people who supplied me with the Koetsu Phono Cartridges. The only Electro Sales I lost were to Krell Amps.
Even Michael Jackson and Quincy Jones were Electocompaniet lovers.

Gosh darn it, some electronics make your music system sound superb. Now, we are realizing PrimaLuna stuff is like that. Go figure.

There's mediocre ho-hum stuff and there's certain pieces that are way too good to be true but true they are.

A good way to tell which is which is to look at eBay used prices for gear. The Krell stuff holds it's price well, so does Schiit stuff.

Tony in Michigan

ps. I'm waiting to learn if Jason decides to have this pair of Amps or keeps his Pass

foxhall's picture
Submitted by foxhall on September 29, 2017 - 7:41pm

My very first exposure to high end audio was in the mid 1990's and the system a very popular combination of Apogee, Krell and Wadia. I remember the owner remarking he preferred 3 hours of warm up for his Krell amplifiers.

Has the optimal warm up time decreased with innovation? Do you think there will ever be a time when A/B amplifiers won't need warm up time?

Do some manufacturers include warm up best practices in their manuals? My Parasound Halo gear manuals don't include this type of information so I was just wondering.

Johnny2Bad's picture
Submitted by Johnny2Bad on October 2, 2017 - 1:26am

Thank you, thank you, thank you Jason for your written words "...The Progression's enclosure and chassis—in this case, the same thing—is machined from a solid billet of aluminum. ..."

Finally, a journalist who gets it ... I tire of reading, in audio and other pursuits, of a product described as "billet aluminum". A billet of aluminum is a lump of metal. There is no reason to purchase one unless a lump of metal was what you wanted in the first place, versus a functional, machined device, and they can be had at much lower cost at your metal supplier versus your audio vendor or automotive performance parts reseller.

Now, if we can only banish the fictitious product, "aircraft grade aluminum" (or it's sister, the Ford Motor Company's "military grade aluminum", another product that does not actually exist), the world will be much improved.

Of course, strictly speaking, you could have left out the "solid" part, as it's redundant (by definition, all billets are solid) but I'm still going to thank you for getting it mostly right.

tonykaz's picture
Submitted by tonykaz on October 3, 2017 - 8:18pm

This Amp chassis is made up of multiple pieces.

It's CNC machined , no big deal considering the tooling we have today. It does not have all that exotic & beautiful a surface finish on the inside.

These aluminum pieces are not heavy, making me wonder about the power transformer.

and

making me wonder if the power supply benefits from one of those $10,000+ Power Conditioners -- or -- has Mr.D'Augostino figured out how to make a power supply that's not susceptible to what ever those Power Conditioners are supposed to filter out.

And

Does this amp need one of those aftermarket Power Cords for $5,000 to help it realize it's full potential ?

And

Of course: will these Amps replace the Pass 'house' reference Amps?

Way back in 1985ish, one of my customers went and purchased a 200W. Krell Stereo Amp that took two people to carry into the guy's house. phew

I was there to see the unboxing of the Beautiful Amp but couldn't see myself carrying the Krell line, the stuff is sooooooo darn heavy and with sharp edges. ouch.

I must say that I've admired Krell but it always seemed to be "Over-kill" type of gear.

The big Chord stuff is even greater Eye Candy.

Tony in Michigan

Allen Fant's picture
Submitted by Allen Fant on October 16, 2017 - 3:40pm

J.A.

recently you had mentioned using a disc of tracks from HiFi News-
where can I get this disc? If it not avail for purchase, is it possible to get a copy that you use? I can send a blank CD-r.
Thank You

John Atkinson's picture
Submitted by John Atkinson on October 17, 2017 - 9:57am
Allen Fant wrote:
J.A. recently you had mentioned using a disc of tracks from HiFi News-where can I get this disc?

This was in a reprint of a review first published in 1987 and the CD is long out of print. Send me an email at JAtkinson at enthusiastnetwork dot com.

John Atkinson
Editor, Stereophile

pma's picture
Submitted by pma on October 31, 2017 - 10:42am

From JA measurements we can see that
A) there is quite high crossover distortion in this amplifier which has not been corrected by appropriate global negative feedback. IMO the level of this crossover distortion is somewhere at the limit of audibility, so it might be audible or not. However, well engineered power amplifier should NOT exhibit such high level of crossover distortion.
B) We can see modulation of amplitude response into dummy speaker load that is quite high and we may say it would be audible. Again, not enough feedback.

Though it may be a nice piece of equipment, the engineering result is disappointing and I am sure that this is not the way how to design for highest sound accuracy. On the other hand, I understand that many listeners will appreciate the amp just for its inaccuracies.

Ali's picture
Submitted by Ali on November 28, 2019 - 12:45am

A good practice for reviewers is to put album screen shot cover here so we know exactly which album should we listen to: in this case, I could not recognize which Maria Callas album Jason refers to. Because they are many versions and I have the same problems in many other reviews too. Thanks.

Ali's picture
Submitted by Ali on December 11, 2019 - 8:24pm

Thanks Jason for review, have you tried progression with its preamp?

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