MEASUREMENTS: Yamaha RX-V781 A/V Receiver. Questionable magazine reviews of "high end" amps (D'Agostino). And thoughts on "hardware audiophiles", age and aging.

For this post, I want to have a look at the performance of my Yamaha RX-V781 as an amplifier. It's not new - I purchased this back in late 2016 to replace my Onkyo TX-NR1009 which I published on previously. Awhile back, I also looked at the pre-outs to examine the quality of this device's DAC.

This was an inexpensive receiver when I got it (as I recall, significantly less then US$700), being part of the "V" (Value) series from Yamaha, a step down from their "A" (Aventage) line. From the outside there's not much to look at, it's a black receiver with the usual buttons, knobs, and LCD screen to tell you the status. There's no swivel-open door to hide buttons like in more expensive models. It's a combination of plastic and metal exterior. Weight is not too heavy at 23lbs, mostly from the power transformer (looks like conventional E-I type, less expensive than toroidal but can provide greater capacity for size with potentially higher magnetic interference however).

The V781 is quite a feature-filled 7-channel amplifier capable of running 5.2.2 Atmos / dts-X, even compared to many of today's devices (see Yamaha specs here). What drew me to this model when I bought it was the fact that it had a full array of pre-outs so I could bring my own amps to the party if I wished.

Interestingly, even though over the years Yamaha updated these receivers with models like the RX-V385 and RX-V685, they never updated the "V78X" product line. My guess it that maybe the higher-end Value series might have been too close to the lower-end Aventages in terms of features and quality. For example the current Yamaha RX-A2A (~US$900) doesn't have a full complement of pre-outs, has more HDMI ins, no second HDMI out and quite similar to the Yamaha RX-V6A (US$650) already.

As you can see, there's a nice array of ins/outs back there with proper binding posts to fit banana plugs as well as those pre-outs bottom-left of the speaker posts. At this price range there's no balanced connection. Phono input is available for MM cartridges. It's a networked device and can accept Yamaha's MusicCast, AirPlay, and services including Tidal. Bluetooth and WiFi capable.

In terms of digital inputs, there are 5 HDMI with 3 of them capable of HDCP2.3 (updated from 2.2 in 2019, important for content-protected UltraHD Blu-Ray players like my Oppo UDP-205 and streamers like the AppleTV 4K). There are also a couple of optical and coxial S/PDIF inputs each.

Note that there is no 5.1 analogue input capability which has become less common these days with the ubiquitous HDMI digital carrying hi-res. Like it or not, over time, it has become less common to see Blu-Ray / SACD players with those analogue multichannel outs.

The role of an A/V receiver is of course to also feed the TV with a good HDMI signal. In this regard there are 2 HDMI 2.0 HDCP-capable outs with the primary output capable of ARC (this is not the higher bandwidth eARC available these days in HDMI 2.1).

One other feature I appreciate is the 12V trigger. Good to have when one has outboard amplifiers to turn on to synchronize with the receiver power on/off.

I. Setting up for the test...

So that I set the context for the tests appropriately, let me lay out what I'll be measuring here.

A/V receivers are complex devices. Arguably, they are too complex for many mainstream consumers. I suspect there are many folks out there who would be overwhelmed just looking at the back of that thing and trying to figure out what's what (and a manual of >150 pages)! The idea of having multiple speakers around the room, running speaker wires all around, then figuring out stuff like which input to use, how to run room correction, bass management, differentiating between whether to use DSP modes and remembering terms like DD/DTS/TrueHD/Atmos/dts-X/etc., multi-zone set-ups are all "turn-offs" except for those of us who enjoy this stuff! In fact, I bet many "old skool audiophiles" don't like the technicality and inconvenience either which is in part the resistance for many to go multichannel even though I believe a good 5.1 mix sounds superior to 2.0 in general.

So, for testing of this device as an amp, let's keep this simple guys ;-). I just want to see how good the V781 is as a 2-channel amplifier so I can compare this to the other amps I've measured thus far. Keep in mind that with more than 2 channels, it's good to have extra power on tap. For this receiver, Yamaha rates it as 110W into 8Ω, 2 channels driven (1% THD, 1kHz). As usual, I prefer testing at the more challenging 4Ω for the majority of what I'll be showing.

Example of level and crossover settings for the speakers in the room set in the DSP configuration when Pure Direct turned off. I've got larger floor-stander speakers front and rear, but happy to roll off the bass at 60Hz to feed low frequencies to my dual subs.

With set-up being complex, I did some homework behind the scenes to check output quality, let me just say that this amplifier objectively performs best with the following settings:

- Make sure not to limit current, so make sure the speaker impedance is set to 8Ω, not 6Ω. You change this by holding the "STRAIGHT" button while turning it on to flip settings.

- Make sure to turn OFF "ECO" mode.

- For best pure analogue quality, use the "Pure Direct" feature to bypass the internal digital conversion and DSP.

Unless specified otherwise, the measurements here will be with those settings in place.

Here she is on my test bench warming up for an hour and getting ready for some measurements...

To be more consistent with how I test other amplifiers, I'll use one of the analogue inputs fed with the older Topping D10 DAC (good enough output quality with better than -100dB THD+N so not really an issue except for the best amps out there). The reason I'm using the D10 is because it has a smoother, well-extended frequency response unlike the D10s' "apodizing" filter setting with rippling below 20kHz. [I still don't understand why Topping used that filter and I hope they could somehow update the firmware to just a standard linear phase steep setting with low passband rippling.]

As usual with my amplifier measurements, I'll be employing the Linear Audio AutoRanger Mk II for automatic switching to provide a standard 2V output to the RME ADI-2 Pro FS ADC which has way more than enough resolution to perform the measurements from amplifiers. Data collection and analysis is with the little Intel NUC computer.

II. Measurements: Gain, Damping Factor, Frequency Response...

To start, I'll use the "AV1" analogue RCA input to feed test signals into the receiver. To get an idea of sensitivity, let's have a look at the amplifier voltage gain when I gradually increase the volume knob to 0dB. I get a value of +27dB at 0dB which is a couple dB shy of the THX unbalanced reference of +29dB. Note that the volume knob can go up to +10dB if you want to push the amp higher so there should be no issues here even with low-voltage source components. Within the amplifier settings, you have the option to cap this maximum value which is a nice feature (I don't need huge volume so happy to cap this at 0dB).

Another parameter I find very important is the damping factor across the audible frequencies. As usual, I measure this with a 4Ω load which I think is more representative of speaker impedance these days. Over the years we've come across amps with low damping (like the Pass SIT-2) as well as high damping (like the nCore NC252MP) which will provide much better control of low-impedance speakers.

Here's the Yamaha RX-V781:

That's very good. A damping factor around 20x across the audible frequencies into a 4Ω resistive load I believe is good for the vast majority of speakers. We can see the "controlled" frequency response with the Sony SS-H1600 bookshelf that I've used as a "standard" in these tests over the years.

Nice. Note the relative "invariance" of frequency response with a Y-axis of just 4dB in the graph above. As expected, the 4/8Ω loads measure "flat". The Sony SS-H1600 speaker, rated at 6Ω does show some very mild frequency fluctuations due to impedance variation. This is minimal, staying generally within 0.1dB thanks to the 20x damping factor - compare this to the Pass SIT-2 for example.

I've already shown in my previous post on this amplifier that it looks like the internal DSP operates at 24/96. To demonstrate this with the amplifier output, let's have a look at the frequency response comparing "Pure Direct" (DSP off) and when we engage the DSP using a 24/192 sweep from the Topping D10 (96kHz bandwidth):

Yup, as you can see, with Pure Direct on (green), it looks like the 96kHz bandwidth signal is passed through. Once you turn on the Yamaha DSP (they call their room correction Yamaha Parametric room Acoustic Optimizer - YPAO), notice the frequency response drops off by 48kHz (internal 96kHz). The "FLAT" frequency response is with the room correction turned on (ie. 'flatten' room modes with parametric EQ), and the "STRAIGHT" (red) setting is just with various parameters like relative time delay and bass management turned on (I had set the roll-off to the sub at 60Hz), but no room EQ correction.

I believe all Yamaha amps up to this point in history are Class AB designs. Here's the frequency response into 4Ω with the phase plot; nice and flat until the DAC filter rolls us off into 96kHz (192kHz samplerate sweep):

III. Single-Tone Harmonic Distortion and Noise

As we move into distortion measurements, let's have a quick peek at the THD vs. frequency sweep graphs for this amplifier operating at various output levels into 4Ω:

Already you can see that we're not looking at a remarkably high resolution device here. Overall it's still quite good with THD better than -70dB (0.03%) at 2V (1W) output at 1kHz where the cursor is. Notice that in each of the sweeps, we see the predominance of odd harmonics, particularly the 3rd and 5th. There are some low-level fluctuations but for the most part, the harmonics stay relatively constant through the audible frequencies.

Okay then, let's now have a peek at a few of the 1kHz FFTs at different output levels:

As you can see, at the lower power levels below 6.25W, indeed the 3rd and 5th harmonics are the strongest. There's a small amount of 60Hz seeping through but not bad, typically below -90dB from the primary signal except at very low levels.

If we gather a number of those THD+N results together, we can then construct the THD+N vs. Power graph:

Not bad at all. Distortions stay below 0.1% from 15mW up. THD(+N) hits 0.1% at the upper power level around 170W into 4Ω. As per my convention, this is all done with 2 channels driven.

The results above are with Pure Direct on. I was curious, what happens when we turn off Pure Direct which then allows the receiver to use its DSP to perform bass management and EQ. Here are a few 1kHz FFTs with the DSP on:

If you compared the THD+N results to the same voltage level above, turning on the DSP (which will require an additional analogue-to-digital conversion internally) does lead to some increase in distortion +/- noise. It's certainly not bad though; about 1dB or less difference up to 1W and 3dB worse in THD+N by 25W (still better than -80dB THD+N). I would not be concerned with using the DSP since the benefits of bass management and adjustments for channel balance in a multichannel system are essential and well worth the small resolution reduction.

Speaking of 2 channels, here's a quick look at the crosstalk at 2Vrms to a 4Ω load measured as seepage of the right into left at 300Hz, and left into right at 4kHz:

I'm seeing a variation depending on the frequency (not unusual) with average around -70dB which is not fantastic but better than most of the other amps I've looked at (the DIY nCore NC252MP achieved close to -80dB and tube Onix SP3 Mk II achieved -56dB for context). 

IV. Multi-Tone Testing: Intermodulation Distortion, TIM, and Triple-Tone TD+N

Having examined the single-tone distortion results, let's move on to what could be more important multitone distortion results.

As you can see above, I'm showing a full panel of the various IMD tests I've used over the years at 1W and 10W into the 4Ω load. On the whole, we see results around -70dB which again is pretty good compared to other amps I've looked at. In comparison, the tube Melody Onix got only around -52dB, the Pass SIT-2 only -30dB at 2V, and the nCore NC252MP typically better than -80dB whether 1W or the higher 25W for those tests.

Notice that there are quite a number of other intermodulation products seen beyond the main ones measured by the software. Also, the odd-order distortions tend to be higher than even order with this receiver/amplifier.

Next, we have the synthetic TIM ("Transient InterModulation") signal consisting of a 1kHz square wave with 12kHz sine at 192kHz samplerate (96kHz bandwidth), measured at 2V and 14.6V output in this instance:

I have to say I was quite impressed by this result! The distortion components for this test came out at around -110dB at the 2Vrms (~1W) level and still around -100dB when the amp output was pushed to 14.6Vrms or around 50W into 4Ω, both channels driven. This speaks well to how dynamic transients are reproduced - that's always a good thing for music and movies alike.

As usual, I like using the Triple-Tone Distortion & Noise figure as a representation of an overall "fidelity" measurement at ~1W (2V into 4Ω, 2-channels driven) for the amplifiers I test here. The signal is a triple-tone at non-harmonic 48/960/5472Hz frequencies which allows us to see harmonic and intermodulation distortions popping up across the spectrum (I captured this up to 30kHz).

As you can see I've got both the left and right channels measured. The top graphs are done with the receiver at "standard" settings, returning a resolution of -69dB. Below, we see the same test with the receiver's "ECO" mode turned on. Notice that the average dropped to -62.5dB with power savings turned on.

Using the Kill-A-Watt meter, I was able to see that indeed, ECO mode does reduce power consumption. On ECO mode when turned on and idle, the receiver uses 31W, and when playing a 2Vrms 1kHz signal into 4Ω, this increases to 39W. With ECO turned off (default), the power utilization was 35W idle (13% increase), and 56W (40% increase) with the 2V, 1kHz tone. Not sure what the ECO mode setting is doing, maybe reducing Class A bias and maybe limiting current as well. I didn't bother testing at higher output levels to look at what happens to distortion - might be interesting comparison curve if anyone has a Yamaha to plot out THD+N vs. output level with and without ECO on.

V. Square Wave and Wideband Noise

To finish off, let's just have a quick peek on the oscilloscope at some square waves:

That's a bandlimited 192kHz (384kHz sampling rate) square wave from the DAC. Good looking morphology and the 2 front channels have excellent balance with less than 0.01V difference (CH1 fluctuated between 1.03 and 1.02V). No significant overshoot on the edges, no ringing.

And if we look out further into the ultrasonic frequencies (to 600kHz):

We see that there is roll-off from 5kHz to 93kHz (the amplitudes are supposed to be 1:1, so this is not as wide bandwidth as the Onkyo TX-NR1009). Otherwise, there's no significant ultrasonic content or noise up to 600kHz. A relatively noise-free ultrasonic range is to be expected with Class AB amps, compared to say the switching noise with Class D amplifiers such as the Hypex nCore NC252MP (at ~420kHz).

VI. Subjective...

Playing an LP on the Technics SL-1200 M3D as well to the Yamaha. Sounds very good with my Denon DL-110 high output moving coil cartridge which is compatible with MM phono input. In retrospect I should have measured the frequency response of that RIAA curve... Maybe another time.

As you can see in the image above, I've cleaned up the sound room audio "rack", removing some of my older devices I haven't used in years. In the process, I decided to even take out my Emotiva XSP-1 analogue pre-amp and just put this Yamaha RX-V781 as the main "centerpiece" to the sound system!

As an audiophile, I think it is a good reality check once awhile to just try out devices like this which would be considered at best "mid-fi" in the eyes of many partaking in the "high end" side of the hobby.  Be mindful of terms like "mid-fi" and pejorative connotations because as a "more objective" audiophile, I think it's important that I let the data plus listening experience help guide the assessment of sound quality rather than marketing terms like this. I don't think one always has to "move forward" with bigger things, more expensive toys, or even claims of "high end" because I don't think there's necessarily even a correlation between price, performance, or public sentiment much of the time.

Inexpensive devices like the DIY nCore NC252MP Class D amplifier I think can already be superior in most ways to most Class AB amps regardless of the price. This is what is supposed to happen with technological innovation and progress. The idea that in 2021 one somehow expects to find the "best" sound quality only in amplifiers that cost >$10,000 or even >$50,000 is patently illogical.

After all these years, this is actually the first time I tried just using this receiver as the main amplifier for the front speakers for any extended listening. I must say that I am actually quite impressed. For 2-channel playback, I was able to enjoy the "QSound" surround effects from Roger Waters' Amused To Death the other night as well as his In The Flesh Live album. The receiver was able to nicely render the spaciousness of these recordings. Tracks like "Too Much Rope" on Amused had the horse-drawn carriage and Ferrari transitioning through my sound room with not just side-to-side range, but also the gradations of depth. The crowd sound on In The Flesh Live enveloped me with a nice sense of presence in the venue. There was even a feeling of height to the sound of the helicopter at the start of "The Happiest Days of Our Lives" - not an easy impression to pull off! The cliché about the "speakers disappeared" applies here with this receiver/amp. 

Achieving a convincing QSound effect on these albums implies reasonably good frequency range, dynamic range and time-domain performance.

I mentioned a few weeks back about Mario Martinez's work with Play Classics. I had the opportunity to listen to another of his albums this week - Guillermo Hernandez Barrocal playing piano on The Romantic Piano (2021, DR13). Wow! Impressive recording (even more notable from a 13 year old at the time). Excellent work on the Schumann "Carnaval Op.9" showing fine technicality and finesse in rendering this suite representing the colorful characters one might run into at a "masked ball".

One can compare a track like Chopin's "Fantasie in F minor, Op. 49" with the same piece on Anna Fedorova's Four Fantasies (2018, DR14) from the Channel Classics label. We can easily compare the variation in emotional expression between the players, how each added their emphases, nuances. By the way, Fedorova started her concert playing at the tender age of 6! Here's her a few years ago doing Rachmaninov's Piano Concerto No. 2, op.18 on YouTube from 2013 with 33.5M views - very impressive for classical music to catch such attention! For the Chopin piece, I prefer Fedorova's version for its sense of authority, flow and pacing. Of course, young master Hernandez Barrocal has many more years ahead of him to continue to hone his craft... Bravo for an amazing job already!

Something else we can compare between the albums above is the way the music was recorded. Both are of solo piano. I noticed that the Play Classics version was recorded and produced with more depth so if I close my eyes, I can imagine the piano in front of me appearing to emanate from just beyond the front wall of my listening room. In contrast, Channel Classics picked a closer mic'ed capture of the piano, making the sound wider, filling the room more. I'm sure listeners will have different preferences as to which is better. The closer recording of Fedorova provides perhaps a bit more intimate detail to the sound of the piano as if we're in the music, but the Hernandez Barrocal recording enhances the space around the piano, of the listener attending a piano recital, the sound being more integrated, that of an instrument sitting in front of you. These decisions made by the recording engineers have a huge impact on the sound quality! I would argue that these differences will overshadow the minutiae that audiophiles might discuss ad nauseum about like PCM (24/96 - Play Classics) vs. DSD (DSD64 - Channel Classics), or heaven forbid what cables were used ;-).

For completeness, the Fedorova Channel Classics SACD also has a multichannel layer which definitely expands the ambience we don't hear from the stereo mix. As discussed for years, I am a fan of multichannel and wish that there were more multichannel music recordings (Apple and their Spatial Audio IMO is a step in the right direction).

It would be silly not to close off the subjective section with anything but a multichannel recording - this is an A/V receiver after all! Well, The Beatles' Let It Be (50th Anniversary Super Deluxe, 2021) was just released last month and the digital edition includes the multi-channel Dolby TrueHD Atmos mix as well as 5.1 DTS HD-Master Audio mix. The two sound different with the Atmos mix being a bit more aggressive using the surround channels on my system. If you like a more "gentle" kind of surround, go for the DTS-HDMA version.

I like the sound of these multichannel mixes by Giles Martin and Sam Okell over at Abbey Road Studios (who else!?). Obviously the extra channels "open up" the sound with expanded spaciousness. The voices sound cleaner, less constrained, and more nuanced. While the studio effects like John Lennon's distorted lead vocal can sound a bit dated on "Across The Universe", intelligibility is great and as was done on Abbey Road in 2019, the surround effects were kept tasteful without excessive gimmickry.

They strategically place the electric guitar to the rear on tracks like "I Me Mine" and "Get Back". Also, the orchestra was spread to the rear on "The Long And Winding Road" which immerses the listener into the surround mix. The center channel along with front speakers were used on "Maggie May" to help spread out the front "wall of vocals".

On a technical note, the Dolby TrueHD Atmos track is 24/48 whereas the DTS HD-Master Audio 5.1 is 24/96. As an old 1970 analogue recording, this is not "hi-res" in any meaningful sense. 48kHz is all you need and on my 5.1 FLAC rip of the DTS-HDMA, I downsampled and dithered it to 16/48 (as I typically do with content like this).

While I loved the music through this Yamaha receiver, no, this is not the highest quality playback I've heard. I think the main issue is the noise floor being higher than my usual reference with the Emotiva XSP-1 preamp + Hypex nCore amp. At higher levels, the 60Hz hum can be heard on a very quiet evening when the world has gone to sleep. Subjectively, I cannot complain about the detail this amp was able to reproduce. Audiophile demo-quality nuggets like Nils Lofgren's "Keith Don't Go" or Yosi Horikawa's "Bubbles" exude plenty of details and subtle nuances even if not the "best" objectively.

Comparatively, I prefer the sound of this receiver to the tube Melody Onix SP3 Mk II with its even higher noise floor and the amount of power this receiver is capable of delivering is heads and shoulders superior to something like the Pass ACA or Pass SIT-2, both of which demand that they be paired with much more sensitive speakers.

VII. Impressions and Conclusions

Okay then, let's summarize the objective results with my usual AMOAR multi-composite score into a 4Ω load:

To be honest, the objective results and my subjective listening impressions were a surprise. While I know multichannel A/V receivers can sound very good for 2-channel playback like my old Onkyo TX-NR1009, I somehow didn't have much expectations for this Yamaha in part because this was even less expensive than the Onkyo; build quality was not as impressive (not as heavy), and I always thought of this more an an entry into Atmos playback for movies. This is why I don't think I even tried plugging my main front speakers into this receiver until now!

Also, the results are comparable with the retro 1978 Pioneer SX-880 receiver in terms of low distortion, and similar damping factor. However, this Yamaha is capable of more power, is multichannel, and of course there's the host of modern digital audio features like DSP.

As you can see, the damping factor of 20x results in just around 0.1dB fluctuation across the audible spectrum with the Sony speaker rated at 6Ω. Compare this with something like the First Watt / Pass SIT-2 and its 1.6x damping factor resulting in 3.5dB fluctuation using the same bookshelf speaker! Yeah, I know, some audiophiles will talk about the ills of feedback (which increases damping) and how no/low feedback sounds "amazing". I personally do not hear a "problem" with higher feedback. Definitely the wide frequency response variability with the SIT-2 is audible (and can be measured through the speaker output) and I don't consider that to be a particularly good thing!

While this amp is certainly not a leader in distortion-free high-fidelity with a 2V triple-tone TD+N of -69dB, this is still quite good subjectively to me. Both the Pass SIT-2 and ACA only achieved -30dB for this. The result I'm seeing here is similar to the Onkyo TX-NR1009's -73dB. It's only with the power amps like my Emotiva XPA-1L monoblocks and DIY nCore NC252MP where we see better results of -81dB and -91dB respectively. I'm also not a fan of the presence of higher order harmonics and intermodulation distortion I see with this amp. However, exactly how this affects the sound subjectively in a negative way, is hard to put my finger on. One could also argue that adding some harmonic distortion can also have an "euphonic" effect by enhancing the perceived complexity of the sound so maybe that "cascade" of harmonics at progressively lower amplitude beyond the 9th might even be "enjoyable".

As for the output power potential of this receiver-as-amplifier, it's very good and I think would be fine for most audiophiles unless you have extremely low-efficiency speakers. It exceeded the manufacturer number of 160W into 4Ω, 1kHz, 1 channel, 0.9% THD by quite a margin! I was able to achieve 0.1% THD+N at 170W into 4Ω, 1kHz, 2 channels driven. This is great for a multichannel amp and it's always good to see when manufacturers publish conservative data like this for their products rather than inflating specifications - great job Yamaha! Needless to say, there was more than enough power here to turn the volume up on music like Guns N' Roses' Appetite for Destruction and related genres. Of course, as a receiver unit, please make sure to plug in a subwoofer or two for the extra impact especially since bass management is so accessible! ;-)

As I've said in the past, don't forget to consider what's "Good Enough" for you and your sound room. To reach that "good enough" point for enjoyment of music with high quality playback, I would recommend focusing on your room acoustics, speakers, and potentially implementation of DSP first. Beyond that, a decent amplifier (even something like this receiver) can often serve the audiophile very well, and DACs these days do not have to be very expensive and I believe even ~US$100 devices like the Topping D10s would not be embarrassed in blind testing compared to kilobucks DACs. As usual, beware of audiophiles who listen with their eyes.

For the time being, I'm actually quite happy with just using the receiver over the next little while! Although there's still quite a "rat's nest" of cables behind the audio rack due to networking, all the speaker cables for multichannel, etc., it is much tidier and easier to operate just a single receiver than separate preamp plus receiver for multichannel and movie playback. Something I might try is to use the pre-outs to power my nCore NC252MP amplifier as a separate amp for better quality to the front speakers.

Looking at the current Yamaha lineup of amplifiers, the Aventage RX-A6A looks like a beauty with a 2-channel XLR input for your external high-resolution DAC plus balanced XLR front pre-out to feed an even higher quality amplifier for stereo playback. Something to consider down the road for an upgrade if I want to just stay with a receiver setup. ;-)

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One of these days, after the Pandemic, it would be nice to check out audio shows again. With regards to amplifiers, I'm very curious to have a listen to something like the Dan D'Agostino Master Audio Progression M550 monoblocks recently reviewed in Stereophile. Jeez, what a monster - 115lb each, $45k/pair. Sure, it looks great if you like the steam punk styling, and it provides plenty of power, but for this kind of price, where it matters around 1W, notice that it's not able to even manage below 0.1% distortion. Furthermore, notice the +/-0.25dB fluctuation with the simulated speaker load suggesting high output impedance (low damping factor). This all suggests a device with very low feedback.

I dunno guys. I know harmonic distortion is hard to hear (as discussed in the blind test results from last year), but isn't it a little silly to spend close to 50 grand on a pair of high-powered amplifiers that can't even consistently maintain less than 0.3% distortion below 10W of power? I would love to see what the 1kHz FFT looks like at 1W! Or maybe even better, I would love to see the TIM signal result with these monsters (wasn't that the rationale for why solid state amps were supposed to sound bad?). Are we saying that D'Agostino has found some kind of "secret sauce" and that this form of distortion pattern sounds amazing and is worth the money? Or should be consider the blasphemous possibility that an amp like this actually might reduce fidelity compared to even much less expensive amplifiers which is what the measurements suggest?

[A side note: I don't understand why Atkinson in his measurements all these years don't just show us the full audible spectrum from 20Hz-20kHz for the 1kHz tone at 1W using a log scale so we can see the 60Hz hum and distortion at the very important "first watt" power level using a tone (eg. 1kHz) that human hearing is highly sensitive to in the full audible spectrum context. For example, with this D'Agostino amp, he splits it into linear scaled 0-1kHz 1W, and does not show us the 1W from 1kHz to 20kHz at all! The only full spectrum FFT we get is with the linear 19+20kHz intermodulation tones at 100W which is good to know about as a "torture-test", but a steady 100W output with these kinds of frequencies is essentially of no significance in real life music reproduction! The suspicious reader could probably imagine reasons why these specific graphs were selected for publication as opposed to other IMO more useful possibilities. As much as I applaud Stereophile for including objective testing over the decades, I suspect there is some element of bias and probably intent to not offend manufacturers in the objective sidebar and the words Atkinson choose even when faced with highly questionable performance at very high prices.]

It's fascinating how in the audiophile press (with the unspoken role of trying to impress readers/consumers), there seems to be a total dissociation between subjective opinion and objective performance. I believe this dissociation is untrue if one really has excellent hearing. Despite what is remarkably poor performance (worsened by an issue with the bias going off for some reason, not the first time D'Agostino stuff had problems!), Mr. Serinus summarizes the sound as:

"For anyone who values colorful and glowing amplification that brings natural timbre and the subtlest of details and dynamic shifts to the fore while supplying a breathtakingly full measure of big-picture dynamics, slam, and top-to-bottom frequency response, the Progression M550s must be heard. They are wonderful amps."

Hmmm... Maybe we should all be aiming for <10 damping factor, 0.15% THD at 1W to experience "colorful and glowing amplification" (actually, the Melody Onix tube amp is sorta like this). Notice the use of those words when describing a solid state amp with fancy meter at the front. Like I said, I think this speaks to the fact that there are audiophiles out there who listen with their eyes (and probably also impressed by size, weight and MSRP). I wonder if the reviewer should go back to "listener training school" for a refresher. I believe this sadly is the state of much of "high end" audio these days and the devices they seem to think audiophile hobbyists are excited by. For electronics, unless we're looking at demonstrable improvements in performance or new features, my suspicion is that there's nothing more to be said about sound quality above something like US$5000 for an amplifier (I think that's actually generous). Beyond that, the real selling point is "luxury" and those non-utilitarian functions.

Needless to say, it would be very interesting to perform a blind test (even single blind) of something inexpensive like this Yamaha receiver vs. the D'Agostino monoblocks! Unlikely to ever see such a thing published in an audiophile magazine since this is likely to scare advertisers. I would not be surprised if the results look like this one done by Matrix HiFi years ago now (done probably a decade ago, notice that of those listeners who even had a preference, more members in the audiophile club preferred the inexpensive system "A").

Interesting to see that the reader comments for that Stereophile review of the D'Agostino monoblocks had to be closed off due to the "uncivil nature of some of the posts". The article I suspect can be viewed as advertising for Dan D'Agostino Master Audio Systems, LLC. In that context, I bet those comments were most unwelcome. [Any bets as to whether Stereophile will shut off comments in the not-too-distant future, just like how TAS, and Hi-Fi+ have already done?]

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Pssst... Want to hear older gentlemen ruminating on audiophile ideas that might not be true, or even real? (Ok, you might not want to. ;-)

Then check out Steve Guttenberg and Herb Reichert's chat on "The Point of Diminishing Returns, is it real?" trying to somehow claim that there's no "diminishing returns" or something like that (which is false). And they talk about stuff like "intangibles", suggest that digital audio is problematic, stuff that's unmeasurable, etc... If you didn't know already, you might have guessed (correctly) that these guys are literally audio salesmen of the "brick and mortar" variety, cutting their teeth in closing deals with handshakes on "high end" amps and speakers back in the day, not the more modern, younger YouTube/"influencer" generation making virtual sales and busking for Patreons.

I find it funny that Herb's available for consultation for a fee as advertised at the end of that talk. Maybe he'll be a good therapist to manage one's neuroses before steering you off to purchase an "amazing" 27W (with 5% THD into 8Ω) $95k amp like the Audio Note Ongaku. Fantastic investment vehicle during times of inflation, although I think fine art and gold bars might be more enduring!

Seriously guys, this is very bizarre stuff and I think it's an argument for why one should put "term limits" on being an audiophile "guru". What kind of hearing acuity and frequency extension do these guys have at this point in their lives? I know this might come out harsh or "ageist", but let's just be honest here.

Age does bring with it benefits. Experience, wisdom, opportunities to teach, opportunities to reflect and hopefully give to the younger generations. However, the idea of these guys being able to hear with excellent ability, then remember what's heard, and then compare differences between devices just doesn't make sense at this point. Even worse, this is the kind of audiophilia that believes that judgments about the quality of audio hardware can be determined when listening outside of the room itself.

I'm sure Herb and Steve can help teach system set-up. Teach and document the evolution / history of the audiophile hobby complete with the exploits of "classic" manufactures over the decades (some of which out of business for decades). Maybe discuss the intricacies of analogue audio, vinyl, and tube gear, sort of like what Fremer does when he's not off listening to electrical power differences and commenting on what an even older, hearing-impaired 92-year-old mother-in-law supposedly heard. But the idea that these guys might be able to provide clear comments around value (and the related "diminishing returns" discussion), or have the ability to differentiate high quality amplifiers beyond their purely subjective idiosyncrasies (some of which might actually be informed by presbycusis) is a bit hard to accept.

The other problem with age is that we can end up "stuck" in preconceived notions. For example "there's a problem with digital" (13:50) is a typical example of these cognitive shackles. Also, stories of old-time "conquests" of having heard classic gear over the decades like the Audio Note stuff feature prominently in the message as well. Look, I understand the joys of owning unique, luxury stuff to some extent... It's "cool" in ways. However, from an audio fidelity point of view, much of this stuff (like low-power tube amps) can sound good with simple "audiophile" music such as female vocals, small ensembles, intimate jazz, even orchestras with short bursts of energy into efficient speakers, but once you bring some complexity into it like well-produced electronica, pop, hard rock, even metal, low power Class A tube jobs like the Ongaku can easily fall apart with little ability to maintain low-distortions for extended periods based on what I've heard over the years (and I don't think using silver in the transformer is going to rescue the amp ;-). The same goes for other things like vinyl with limitations aplenty!

Later this year, I turn 50 myself. No longer a "young" audiophile and on my way to joining the white-haired nerds walking around at audio shows (don't worry, I love nerds). Already, I would not personally consider purely subjective opinions worth sharing other than as anecdotes with friends who can contextualize what I might be describing. To speak like these guys about hearing things over time, especially Reichert's comment at 10:05 claiming "you don't go old and deaf... I actually believe it's the opposite", all that stuff about "recognizing a matrix", is remarkable! It's hard to know whether this is just poor insight or an overvalued ego. In any event, apparently he can walk into a room and "recognize that matrix", and can tell how "speakers can throw the sound into the room... the density of the sound" that others don't notice. Clearly this man has been endowed with the much sought after, spoken of over the generations in whispers and myths, yet rarely ever demonstrated in blind listening, aureus auribus - Golden Ears.

I can imagine when I get to 60, I might still be interested in audio stuff, but I surely will be one step closer to audiophile retirement and likely will see myself as more "music lover" rather than "hardware audiophile" because I think fidelity itself will be less important as I get older. I'd certainly be very careful about making claims that hearing/perceiving gets "better" with age! Psychologically, nobody wants to get older and recognize that his/her abilities are no longer at the peak. Youthfulness (and beauty) is always in vogue, but as we get older, there is something to be said about accepting our limits and not overstepping and claiming a level of certainty about things (like perception of sound getting better) when it simply sounds foolish, going against what we know about biological mechanisms. Even worse is that these guys have zero evidence to back up their claims that such concepts like "density" and "believable corporality" are even "things" other than their own psychological constructs. I simply don't think there's any wisdom to speak like this. And it certainly does not appear to be accepting the effects of age with gentlemanly grace.

Good luck out there, dear audiophiles.

Whether you experience "believable corporality" or not in your system, I wish you happy listening and deep enjoyment of the music. Happy Thanksgiving to the American friends.

PS: Don't bother with 24-bit Adele 30 - good 'ol 16/44.1 CD is more than good enough for this content with DR6 average only. I know about all the wildly positive reviews, although as an album, it seems alright on first listen but too self-indulgent, sad and just not enough enjoyment for me, simply put. I'm sure it'll strike the right chord with some folks (sure, it might be "her most honest album yet"), but I think one has to be in a sympathetic mindset for this. I wasn't as captivated as with 21 which remains my favourite of her albums along with Live at the Royal Albert Hall.

If you're a vinyl collector, it looks like there will be a lot of copies of the album out there, but Amazon's 30 (White Vinyl) edition might be worth more in a few years as a more unique collector's item. Just sayin'...  ;-)

Addendum:
There's a discussion in the comments about listening for the "dog whistle" in Sgt. Pepper as a quick "test" of frequency response. This can be found right at the end of "A Day In The Life" right before the loopback gibberish. Around 5:08 or so on the 2009 remaster CD:

Alas, at almost 50 years old, I'm not able to hear the 15kHz tone although I can hear some of the lower frequency noise in that region, but not the high-pitched fundamental.

And here's a graph of average hearing frequency response and age (by decades) - Eggermont's book The Auditory Brain and Age-Related Hearing Impairment (2019):

Notice it's not just a roll-off in high frequencies, but also the reduction in hearing thresholds across the frequencies with age. Alas, such is life. Embrace it!