Solid State Power Amp Reviews

Ayre Acoustics VX-8 power amplifier Page 2

Silence of the Equilock
A test of whether you've purchased an ordinary hi-fi component or a special one is how many of your favorite recordings it makes sound new—how many favorite albums seem freshly imagined when experienced through the component. No component is entirely transparent; each reproduces recordings in its own image. The VX-8 made familiar records new again. It wasn't so much casting recordings in a new light as digging deeper to reveal more of a recording's sonic architecture; a different kind of light induces a different reflection. What's more, the VX-8 made all the vinyl records I played sound more listenable, regardless of era or genre; none suffered from the experience (footnote 1). It didn't make a bruised '50s Columbia classical LP shiny and new, but it did cast it in the correct musical milieu.

I spent hours pulling out and playing my usual test records to gauge scale, tone, texture, and the like through the VX-8's sonic lens. Whenever I was sated, I moved on to something new: Francis Bebey's African organ gems (African Electronic Music 1975-1982, LP, Born Bad Records BB039); Paulo Vanzolini's '70s Brazilian jazz (Onze Sambas e Uma Capoeira, LP, RGE XRLP-5.321); FSOL's '90s-era British morph-tronica (Dead Cities, LP, Virgin Records 7243 8 4206819); Don Cherry's avant jazz ("Mu" First Part, BYG/ Actuel 529.301). In all these genres, the Ayre unearthed fresh sonic details and ambient information, doing it in organic, wholistic fashion, with more than a little drive and spot-on color. The VX-8's frequency and dynamic ranges were so uniformly sleek and seamless that I didn't dare dissect each recording's sonic elements, lest it lose its beauty. That isn't how we experience music—not when it's good—so why should I report it that way?

The Ayre's detailed sonic panoramas offered frequent surprise and excitement. Its rhythm, even-keeled pacing, and toe-tapping sonority paired well with the Sugden LA-4 preamp, transmitting its crispness and acuity while bringing corporeal images, a sense of ease, and a deep black background to the listening party.

Driven by the VX-8, McCoy Tyner's Reaching Fourth (Impulse! A33)—Tyner's second album as a leader—burst out of the Volti Audio Razz SE speakers with tremendous briskness, the Sugden/Ayre combo working in perfect tandem. Roy Haynes's drums stung; Henry Grimes's bass sounded soft but tonally true. The VX-8 had a sweet spot for jazz.

Carmen McRae's Alfie (Mainstream 56084) won me over through the Ayre, the singer's eloquent vocals framed as tonally rich, liquid, with sharply defined leading edges via the Ayre, as the orchestra practically sighed Don Sebesky's arrangements behind her in a superscaled studio presentation. The Ayre paired microfocused images with broad spatial information; McRae's voice was like a north star atop the orchestra's deep-space spell.

A favorite setup tool of Mike Trei, Shelly Manne & His Men At the Blackhawk 3 (Contemporary S7578), positioned the instruments in "I Am in Love" hard right and left—it's recorded that way—but the sound was utterly natural, the Ayre, Hana, Goldnote, VPI, Sugden, and Volti components collectively disappearing.

The Ayre VX-8 also conquered the volume and intensity of rock. On Free's Fire and Water (A&M SP 4268), Simon Kirke's deep-pitched, rumbling toms were reproduced with more rigid physicality than I've heard on any hi-fi in recent memory. It recalled—called back—the sound of Fire & Water buried in my "mystic chords of memory," delivering chills I recalled from my misspent youth. On the emotional chart, this music via the VX-8 was an easy 10. The Ayre captured the essence of these recordings with pellucid transparency and that shimmering, golden trademark sound.

Through the Sugden/Ayre combo, images were stable. The VX-8's low end was equally satisfying, though on some older jazz records a mite soft compared to other solid state amps. But it reproduced Bernard Purdie's bass drum, in Steely Dan's "Babylon Sisters," from Gaucho (LP, MCA/VIM 6243), with tautness and smack-to-the-skull clarity; meanwhile, the tonal color was practically wet. The VX-8 reproduced the whole of Gaucho with an immaculate meticulousness that mirrored Becker and Fagen's own, rendering a squeaky-clean soundstage that managed to sound both clinical (the recording's contribution) and true (the Ayre's). The VX-8 repeated that feat in the subbass-in-deep-black-space of J.S. Zeiter's Magnetic North EP (Mosae Records MR001). A measure of the resolution, punch, and liquidity I heard came from a recently installed Hana Umami Blue MC cart, but the Ayre let the Umami sing, leaving nothing to the imagination.

In my system, the Ayre VX-8 glistened, reproducing soundwave-ingrained discs with intimacy and presence. It proved graceful, even lithesome, exuding a sense of elan that few solid state amps have matched in my NYC hobo harem. It made Ella Fitzgerald sound even more playful and soulful; Steely Dan extra fusspot and perfectionist; the German pressing of the Beatles' Magical Mystery Tour (EMI Electrola 1C 062-04 449) it rendered uber surreal. And when extra firepower was required, as in the opening salvos of Rimsky-Korsakoff's Scheherazade (Classic Records LSC-2446), the Ayre punched me with its power and voluminous soundstage, from the music's gentle flute and violin to shuddering brass and bowel-rupturing strings. Revealing microdetails set in large sonic panoramas, the VX-8 created a signature similar to the Ayre EX-8 2.0 integrated but with improvements in spaciousness, physicality, and overall refinement. The two amps are equally textural, a standout trait of all Ayre amplification.

Sudgen meets Ayre
Charles de Gaulle may have said "silence is the ultimate weapon of power," but when I exchanged the Sugden LA-4 preamp for the Ayre K-5xeMP, the difference in how the two machines depicted the character of power left me anything but silent. I sensed an overall loss in crispness and upper frequency extension, yet the K-5xeMP created a bigger soundstage with larger images, like going from a school auditorium to the Roman Colosseum. Music gained weight and got more immediate. A downside: Previously unheard vinyl surface noise became evident. Tone benefited from greater saturation, while congestion in the lower mids made me realize the deficiencies of my listening space when a system outputs more low-frequency information than my room can manage. The Ayre K-5xeMP preamplifier was a natural fit for the Ayre VX-8, though the Sugden's upper-tier brilliance and liquid specificity made it an equal contender.

Curious as to further sonic changes, I left the K-5xeMP inline and swapped the VX-8 for the Pass Labs XA-25 power amp. Rated at 25Wpc into 8 ohms, 50Wpc into 4 ohms, I wondered if the Pass Labs would equal the muscle, much less the sleekness and smooth-flowing personality, of the Ayre.

There was far more difference between the Sugden and Ayre preamps than between the Pass Labs and Ayre power amps. The Pass Labs XA-25 amp presented greater note attack than the Ayre VX-8, as heard in Philly Joe Jones's bass drum accents in Miles Davis's "Oleo" (Relaxin', Prestige PRLP 7129), and in the steelier, leading-edge tone of John Coltrane's tenor saxophone. The Ayre depicted a sweeter top end on this recording and a fuller, rounder representation of Paul Chambers's acoustic bass. Generally speaking, the Pass Labs asserted a more forthright version of musical truth than the Ayre, whose silkier but equally transparent interpretation I found equally fascinating. The Ayre's purity and seamlessness was its sonic signature; the Pass Labs' was its boldness, attack, and slightly larger soundstage.

Conclusion
For current owners of Ayre Acoustics amplification and those hoping to bring the brand's sound to their system, the VX-8 would be a worthwhile, relatively affordable purchase. The amplifier worked seamlessly with older components including its sibling Ayre K-5xeMP (which sells for $2000–$3000 used), as well as the current Sugden LA-4, and I bet it would sound fantastic with my Shindo Allegro two-box preamp. (Ankle surgery prevented me from extracting the Shindo from its secure space.) With ample power and even sound, the VX-8 gelled easily with the highly efficient Volti Audio Razz loudspeaker. It satisfied my inner music jones while spinning vinyl or streaming digital.

The VX-8 extends Ayre's reputation for refined amplification that commendably reproduces music of all genres while asserting its singular, special sound, as unique today, under the guiding hand of Ariel Brown, as with its originator, Charley Hansen. A heartfelt, shout-it-from-the-rooftops recommendation.

Footnote 1: This is a point that Charley often emphasized: A good piece of hi-fi equipment should always make music sound better.

COMPANY INFO
Ayre Acoustics Inc.
6268 Monarch Park Pl. Suite B
Niwot
CO 80503
(303) 442-7300
ayre.com
ARTICLE CONTENTS

COMMENTS
Allen Fant's picture
Submitted by Allen Fant on September 22, 2023 - 11:04pm

An excellent review- KM.
Always good to read and see a new AYRE product.
Happy Listening!

MFK's picture
Submitted by MFK on September 23, 2023 - 9:59am

Love your reviews. Your music selections are eclectic and always introduce me to new and excellent discoveries. Thank you!

georgehifi's picture
Submitted by georgehifi on September 23, 2023 - 2:01pm

Isn't it great to see the actual real square wave under test coming out of an amp, without the need of the dreaded AUX-0025 Class-D filter cloaking device that makes a Class-D's squares wave look reasonable if not real and what disgusting noise really comes out of them and onto your speakers.

PS: Love the high input impedance, means NOTHING has an excuse not being able to drive into it, every thing should be that high, might be noisy if switched on with nothing attached, but who does that anyway.

Cheers George

John Atkinson's picture
Submitted by John Atkinson on September 25, 2023 - 6:29am
georgehifi wrote:
Isn't it great to see the actual real square wave under test coming out of an amp, without the need of the dreaded AUX-0025 Class-D filter cloaking device that makes a Class-D's squares wave look reasonable if not real and what disgusting noise really comes out of them and onto your speakers.

You have made this point in other postings, georgehifi. A class-D amplifier's squarewave response shows the ultrasonic switching noise, which is always present with these amplifiers. But what I am interested in uncovering with the squarewave test is not noise but signs of instability. Using the AP filter eliminates the ubiquitous noise and reveals overshoot and ringing, if present.

John Atkinson
Technical Editor, Stereophile

georgehifi's picture
Submitted by georgehifi on September 30, 2023 - 9:41pm

Didn't matter when that filter wasn't use on the 175w CI and Belcanto amps way back, showed the switching noise and if the was any instability ringing that also would show up, so you get to see it all without the AP filter. And a bonus is it shows how effective the switching noise filter in the amp/s is also.

https://www.stereophile.com/images/archivesart/805CIAfig2.jpg

Same also with the Belcanto design Black
https://www.stereophile.com/images/615BCBfig13.jpg

The Halcro Logic had quite a bit of switching noise on it output, which you also commented on being quite large, delicate efficient tweeter coils could get warm with this on them 24/7. I had to replace a pair of Wilson/watt 7 speaker teeter diaphragm/coils because of slight distortion from both, when I opened them up both coils were very "blued" compared to the new replacements, nothing had been blown up and he's not a loud listener, he had big mono DM Halcros not the Logic here, and Nu-Force Reference 9 v2 mono's, one or the other "blued" the voice coils.
https://www.stereophile.com/images/archivesart/406Halfig01.jpg

Cheers George

Ortofan's picture
Submitted by Ortofan on September 23, 2023 - 7:29pm

Charley Hansen's "way of thinking and design" has resulted in a "100 watt" power amp that overheats and shuts down when asked to output a mere 20 watts? Or, is this part of Ariel Brown's "core design thinking?"

Far better heatsinking (for thousands less) with the Parasound Halo A 21+.
https://www.stereophile.com/content/parasound-halo-21-power-amplifier

Axiom05's picture
Submitted by Axiom05 on September 24, 2023 - 3:32am

I was concerned/confused about the heat issue as well. But, it can produce a square wave w/o a special filter, what more do you want? Haha

Dennis in NJ's picture
Submitted by Dennis in NJ on September 24, 2023 - 9:44am

Ayre's 8-series products are "modular designs". The amp section of the VX-8 is very similar to that of the EX-8 2.0 integrated hub. Both are rated at 100 watts into 8 ohms. Both suffered overheating issues when measuring THD+N in bench testing (as summarized next). When JA measured the THD+noise of the Ayre EX-8 2.0 he did so at 10 watts into 8 ohms. At 40 watts into 2 ohms he could only test one channel at a time. Driving both channels at 40 watts into 2 ohms resulted in overheat shutdown. Notably, there was no overheat at 10 watts into either 8 or 20 watts into 4 ohms when measuring THD+N for the EX-8 2.0 integrated hub. However, the VX-8 THD+N was measured at 20 watts into 8 ohms (twice the dissipation) and suffered shutdown after a few minutes operation. As mentioned in the review-- after cooling and reset, measurements could be completed, presumably before hitting the overheat time limit. Which leads to the question: why didn't JA test the VX-8 at 10 watts into 8 ohms, as he did with the EX-8 2.0 integrated, after experiencing VX-8 overheat at 20 watts? Would the VX-8 have no issues, like its integrated sibling? Further no THD+N measurements were attempted on the VX-8 into 2 ohms. Perhaps at 10 watts power into 8 ohms (40 watts into 2 ohms), this could have been accomplished--even if one channel at-a-time. Yes this is indeed nitpicking. But consistency between reviews is important to the reader for their interpretation of the results. Looking on Ayre's website: neither the EX-8 2.0 or VX-8 have 2 ohm power ratings in their specifications. So why check at 2 ohms on the EX-8 2.0, and not the VX-8? Don't check 2 ohms, because the VX-8 had issues at 20 watts into 8 ohms? Again, consistency would suggest halving the power to 10 watts/8-ohm a rechecking THD+N. To assess how the VX-8 performed against its identically rated EX-8 2.0 integrated in this bench test. Nitpicking indeed! The bottom-line is yes, the 8-series amp sections would appear to benefit from increased heat sink area in this static bench test. However, under dynamic signals of music playback no overheat issues were reported for either product in their respective reviews. And yes there are other less costly amplifiers that don't overheat at a fraction of their max rated power in THD+N tests, but they probably also do not have the same "sound" as Ayre products (as described in the VX-8 review). But for these two products reviewed, I believe a little more consistency in measurements would be of benefit.

Ortofan's picture
Submitted by Ortofan on September 24, 2023 - 11:39am

... subjective reviews, either, since the Parasound amp was evaluated by a different reviewer than the one for this Ayre amp.

However, KR characterized the Parasound amp as "impossible to fault." Further, he states that it "is remarkably powerful, transparent and quiet" and it "imposes no constraints on one's desire to listen through it to the recorded performance or to experience the size, weight, and dynamics of the original event."

CG's picture
Submitted by CG on September 24, 2023 - 4:16pm

Your argument makes good sense.

You could ask some other questions along those lines:

Why measure distortion at 50 Hz? That should be pretty much the easiest part of the audio with regard to distortion. That's especially true for amplifiers using global feedback.

There's great reason to measure distortion at 1 watt output. But, why not also at 5 or 10 watts? Unless you have very inefficient loudspeakers, output levels beyond 10 or so watts are going to be distorting your hearing system. Higher power output levels are interesting, of course, but not as relevant to your living room.

Along the same lines, why not perform multitone tests at some normal listening level power? That would be more representative of actual usage. Audio Precision test systems have this function built-in. Some of the excellent free software packages do this, too. (It would make sense to use "pink" weighting on this test, so that the power rolls off with increasing frequency, like music.)

I get that there's an entire legacy of reviews that should be respected. But, maybe it all could be better today.

John Atkinson's picture
Submitted by John Atkinson on September 25, 2023 - 6:22am
CG wrote:
Why measure distortion at 50 Hz? That should be pretty much the easiest part of the audio with regard to distortion. That's especially true for amplifiers using global feedback.

This follows Martin Colloms's amplifier testing for Hi-Fi News when I was that magazine's editor in the 1980s. The idea is to examine the amplifier's output spectrum with a signal a few Hz away from the AC power-line frequency. The test will therefore reveal power supply issues.

CG wrote:
There's great reason to measure distortion at 1 watt output. But, why not also at 5 or 10 watts? Unless you have very inefficient loudspeakers, output levels beyond 10 or so watts are going to be distorting your hearing system.

I don't examine distortion at 1W as it will almost always be buried beneath the amplifier's random noisefloor. But I do look at the distortion spectrum at higher powers - see fig.8 in this review, which was taken at 20W into 8 ohms.

John Atkinson
Technical Editor, Stereophile

CG's picture
Submitted by CG on September 26, 2023 - 11:44am

Understood. But, let me explain my reasoning for suggesting different testing.

For several years, we used a Wavelength Audio Proton DAC. Its output voltage when operated as recommended by Wavelength and the Stereophile review is just about 900 mV for a 0 dBFS signal. In other words, that's the limit. The Proton was connected to a preamp that had a maximum voltage gain of unity. The power amplifier had a voltage gain of just over 18 (~25 dB). Do out the math, and you find that the maximum voltage output from the power amp was ~16 Vrms. That's for 0 dBFS source material.

The electronics all fed a pair of Vandersteen 2Ci's, in a room about 20 feet by 15 feet, with openings into stairs and other rooms near the back.

Any music that was recorded close to 0 dBFS was impossible to listen to with the volume control at maximum on that system. Or, even close to it. It was painful and not something we would want to do here. It definitely violated any reasonable hearing health standards. How Manny Noriega stayed in that hotel, I will never know.

The Vandersteen loudspeakers are certainly not what would be consided high sensitivity. The room is not tiny. It may not be worst case in terms of power requirements for a home system, but I'd bet it's in the top quartile of that group. 16 Vrms into 8 Ohms is 32 watts. That was the maximum for the system, and that was too much power.

So, I decided that there was no reason to have a power amplifier that produced more than 32 watts. That was even stretching the limit. We plain could not use even 32 watts. There are certainly reasons why power amplifiers that could make more power might sound better, but it wouldn't be because we needed or could use more power than that. A perfect 32 watt amplifier would do the job better than a less perfect amplifier that could produce hundreds of watts.

Later, I used this method to more accurately determine the power that we could use:

https://www.diyaudio.com/community/threads/a-test-how-much-voltage-power-do-your-speakers-need.204857/

My results were that 15 watts would do the job. That was for loudspeakers that are on the lower end of the sensitivity scale in a room probably as large in volume as used by most people for music listening.

So, my point is this: Stressing an amplifier to the corner cases might be interesting for testing and certainly makes for lively discussion on the internet, but it doesn't really say much about how the amplifiers would perform in actual use. It's far more important to see how the amplifier performs in the range of a watt or less up to maybe 15 or 20 watts.

In addition, it's probably especially important to test in frequency bands where the human ear is most sensitive for both the fundamental tones as well as distortion products.

Did I explain that well?

The tests traditionally performed aren't wrong, per se; they just might be improved upon. We've upgraded our system quite a bit since the days with the Proton DAC. I think testing could be upgraded, too.

End note: It could also be that testing doesn't tell much about the perceived sound quality, so my observations above are just bunk.

Ortofan's picture
Submitted by Ortofan on September 26, 2023 - 8:40pm

... all of the program material to which you listen will have been recorded/mastered with an average RMS value no less than -12dBFS.

As the FAQ for the test points out, classical and some jazz recordings might be mastered at -22dB to -24dB. In that case, your maximum 15-watt power requirement increases to about 250 watts.

Perhaps you've seen the video of a Harbeth demo regarding peak power requirements. The Monitor 40 speakers are driven by CH Precision power amps, which have peak reading power meters. The peak power displayed during the demo was, at least, 600 watts. The program material was Laptevinmeri/Laptev Sea by Pan Sonic.

Demo video: https://www.youtube.com/watch?v=Y3WpRY-EtX8

Laptev Sea: https://www.youtube.com/watch?v=XhuJxdaU87I

CG's picture
Submitted by CG on September 27, 2023 - 6:59am

I think you may be misinterpreting things a bit.

What you do for this test, or, at least, what I did, is to find the volume setting that is the loudest you ever play anything with. (I ignored a couple albums that I know were mastered at well below 0 dBFS - easy to observe in an audio editing package. These albums need more system gain to be played at a reasonable level, but there you just increase the system gain to make the maximum output level the same.)

Once you've established that volume control level, you play the -12 dBFS tone and measure the voltage. That's it.

As described in the thread, -12 dBFS was chosen because it's low enough in level to not damage any of the system components, including your ears. It's also high enough that it's easy to measure on an RMS voltmeter. The tone could have just as easily been at -22 dBFS, -32 dBFS, or -60 dBFS. It has nothing to with how the recordings are mastered. It's just a pragmatic level to deal with. It's 12 dB - 1/4 the voltage - below the maximum level your system can play with a recording mastered with its peak at 0 dBFS. You can't go any louder.

Assuming that the loudest we ever listen, and then some, is the loudest we'd ever want to listen, 12 dB above that (250 versus 15 watts) wouldn't be enjoyable at all.

In any case, as I first mentioned, our system at the time could only get to about 32 watts maximum, even with the preamp gain set to 11, I mean full volume. We (I keep saying "we" - we being my wife and I) never once found that the volume was too low with any recording.

One other reference point: https://www.stereophile.com/content/ayre-acoustics-ax-5-integrated-amplifier

"As Hansen puts it, "Since most preamps are used anywhere between –10dB and –40dB for an average listening level,"

This is consistent with what I found. Since Ayre has always preferred balanced interconnections, the typical DAC used within an Ayre system has about 7 dB more output voltage than the Proton I was using at the time I made my measurements. Note that the maximum gain of Ayre preamps is nominally 0 dB.

You may have noticed in the poll associated with the DIYaudio test that a very large percentage of the people who performed that test had very low voltage requirements from their power amps. I guess I'm not alone in this.

But, whatever people want to do with regard to any and all of this is entirely good by me. It's a hobby for most of us. I just wanted to highlight why at least some of us might be very interested in an amplifier's performance at some level between 1 and 20 watts output. It seems like there's little interest in that after all, so I'll just let it drop here.

hiendmmoe's picture
Submitted by hiendmmoe on September 24, 2023 - 4:08pm

Sometimes when a founder passes there’s no one to pass the torch off to and the company fades away.
Sounds like Ayre is in good hands. Long live High End Audio!!!

JRT's picture
Submitted by JRT on September 28, 2023 - 1:21pm

In considering this Ayre Acoustics VX-8 ($6.8k) two channel stereo power amplifier, compare it to the Benchmark Media Systems AHB2 ($3.5k).

https://www.stereophile.com/content/benchmark-media-systems-ahb2-power-amplifier

https://www.stereophile.com/content/benchmark-media-systems-ahb2-power-amplifier-measurements

Benchmark AHB2 is approximately half of the price of the Ayre VX-8, while AHB2 exhibits similar bandwidth and similar power output, but at lower noise and lower nonlinear distortion, is much more efficient, and exhibits much cooler operating temperatures.

The price difference is more than enough to also buy a Benchmark LA4 Line Amplifier ($3.0k) control preamplifier.

https://www.stereophile.com/content/benchmark-la4-line-preamplifier

https://www.stereophile.com/content/benchmark-la4-line-preamplifier-measurements

In his review Kalman Rubinson observed and concluded, "The LA4 is probably the most transparent and revealing audio component I've ever used. It does not seem to leave any fingerprints on the sound. It has a useful array of inputs, outputs, and functions, and the use of sealed relays for volume and input selection assures a long and noise-free life. Benchmark might improve on the display and remote control, but I do not have any criticism of the LA4's sonic performance."

John Atkinson summed up his measurements with the comment, "Benchmark's LA4 is the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered."

Or, instead of the LA4, add another $200 to the price difference to buy the Benchmark HPA4 ($3.5k) which is similar to the LA4, but adds a very good headphone amplifier.

MikeSTL's picture
Submitted by MikeSTL on September 30, 2023 - 9:39pm

I, too, read the reviews for equipment evaluations as much as music recommendations.

Suggestion: Would it be possible to begin including a separate page similar to the Specifications page listing the tracks and sources used in the review? This would make it easier to cut and past the track titles into Roon, Tidal, Qobuz, etc.

Just a thought. Anyone else think this would be useful?

dumbo's picture
Submitted by dumbo on October 12, 2023 - 6:14pm

Come'on man...get your sh$% together Ayre. Take this as harsh criticism from an actual fan and previous owner of several of your model lines; all of which I loved.

I can think of several Amps that I have owned in the past at a fraction of the cost of this one that you could damn near fry an egg on the top plate and they never shut themselves down trying to output a fraction of their advertised rating. And this is after 6-8hrs straight of taking a pure beating over 100db at college parties, house parties and just for the hell of it at times (Adcom, Pass, Classe, Rotel to name a few examples)

How are these kinds of issues allowed to leave the factory on their way to the consumer without being noticed? These Audio companies must know what kind of testing they will go thru when submitted to Stereophile.

The embarrassment is avoidable of having an audio rag discover the equipment's short comings. Just test that sh*& till your blue in the face before sending it out the door. If it cant take a real world beating then send it back to the drawing board. Simple as that. This goes for every audio company, not just Ayre.

scottsol's picture
Submitted by scottsol on October 15, 2023 - 8:48pm

I personally applaud a company that designs its products for its customers rather than the press.

I anxiously await reports from customers experiencing excessive high temperature shut downs.

pma's picture
Submitted by pma on October 26, 2023 - 12:07am

I wonder how an amplifier with distortion profile like this one, dominated by class AB output stage crossover distortion not corrected by FB action, can get quite positive rating by J.A. ("The Ayre Acoustics VX-8 offers respectable measured performance,")

CG's picture
Submitted by CG on December 18, 2023 - 10:37am

Crossover distortion? Feedback?

A very reputable designer of equipment who uses lots of feedback in his designs seems to disagree with you on the value of feedback when it comes to crossover distortion.

https://benchmarkmedia.com/blogs/application_notes/131424519-amplifier-crossover-distortion

Besides, I'm not seeing any real evidence of crossover distortion in the shown plots. I just see harmonic distortion. I'm certainly missing something - please show me what I'm not seeing.

pma's picture
Submitted by pma on December 18, 2023 - 10:57am

It is evident from the distortion spectra that the output stage is in highly biased class AB. At the moment when the output stage leaves class A (I = 2 x idle current) and moves to class AB, you can see the crossover distortion resulting from infamous Gm doubling (higher Gm in class A) and transition from A to AB. See the knees in Fig.4. e.g. Low loopgain does not correct it and the level of distortion is high, with high order harmonics forest spread to infinity. The famous designer spoke about totally different circuit.

CG's picture
Submitted by CG on December 18, 2023 - 12:44pm

OK, but I'm not quite following why you think it is crossover distortion, per se. Yes - the amplifier appears to be highly biased class AB. I don't think that's a secret and that should be evident to anybody looking at the box. There cannot possibly be enough heat sinking capability for it to operate as class A even at more than a few watts.

Perhaps it's because I never considered Gm doubling to be crossover distortion. After all, it doesn't actually happen at the crossover point, only on each side. Semantics, perhaps.

My understanding is that the VX-8 is completely open loop in its design. So, low loop gain would not be relevant. That could be wrong on my part, and Ayre could be lying on their web page. No idea. I've never even seen a VX-8.

My point about crossover distortion and John Siau is that he explained why crossover distortion often cannot be fixed with feedback because of the bandwidth of the crossover distortion relative to the bandwidth of the feedback system. But, that's not relevant here, either, if the open loop architecture description is true.

jmimac351's picture
Submitted by jmimac351 on October 29, 2023 - 11:32pm

I have not heard the amp reviewed here, but I have owned a KX-5 Twenty preamp and VX-5 Twenty amp for a year now. I used the VX-5 Twenty to drive a pair of Magnepan 3.7i speakers, without a single issue. I'm now using it with Wilson Audio Deutte speakers. I don't care how any of this stuff measures, whether it shuts down during some lab test, etc. What I do care about is that it's the most musical solid state equipment I've ever heard. I am no expert and I have certainly not heard everything. What I have heard and still own are full tube Joule Electra OTL amp / preamp, Pass Labs XA, Coda, Levinson... I forget what else. There is something about the "Rightness" and Musicality of the Ayre gear that makes me think it is going to be hard to replace / do without. Any sort of consideration along those lines would be in terms of making sure I could sell the latest contestant without losing money, and the Ayre gear would be waiting to show it the door (likely).

With the Ayre gear, I want for absolutely nothing. I'm just happy I was able to afford it at used pricing. Prior to owning the Ayre gear I was a "tube guy"... any tube lover looking for a viable replacement for tube musicality would be well advised to hear this stuff. There is something special and different going on... and I'm glad Ariel is carrying the ball forward.

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