As some of you know, I await the publication of my own hardware reviews like a kid anticipates Christmas—not because I want to re-read my own words, but because that’s when I finally get to see our measurement specialist Diego Estan’s objective data for the first time. I see those measurements when you do, dear reader, and not a minute before.
Well, that’s usually the case. With my recent review of the Dayton Audio HTA200 integrated amp–DAC, I got a sneak peek at the bench testing because I was the only one of us with a contact at the company and there were some questions about how this “Hybrid Tube Amplifier” handles incoming analog signals. After a bit of asking, we were told, “The analog signals (Aux and Phono) are not sent directly to the tube preamp and AB amplifier. All signals are sent through the internal processor in the HTA200.”
Ooh, a right proper scandal! Especially for a product that touts the preamp “tubes’ subtle character and warmth.” Surely, this would explain what I heard in my subjective evaluation:
As I said in the intro, it’s pretty clear that the tubes on this thing are actually in the signal path. Do they make an audible difference in the sound? Frankly, I don’t know and I don’t care. The HTA200 sounds fantastic, and that’s what I care about. The glow of those valves over the dancing VU meters makes for one hell of an engaging sight, though, especially in a dark room. If that doesn’t matter to you, I’m not here to argue. But speaking for myself, having something this nice to look at when I’m hearing my music sound this good is quite a treat.
Of course, I’m being completely facetious here. If I couldn’t hear any meaningful contribution from the tubes in the signal path in the preamplification stage, then I’m certainly not going to hear the effects of a competent ADC. Monty Montgomery demonstrated that beyond a reasonable doubt ages ago.
Mind you, I’m not saying the HTA200 sounded flawless—merely that it sounded way better than you’d expect for a $350-ish integrated amp/DAC, and I don’t think any of its sonic imperfections could be attributed to digitization. And to be fair, I actually enjoyed most of its sonic imperfections as character. But I guarantee you, somewhere out there, there’s someone who was drawn in by the promise of “tube sound” and will reject this incredibly fun little integrated amp because all of that supposed pure-analog goodness has been sullied by the taint of digital whatever-ness.
Granted, I can already predict there are some analog hardliners reading this whose skeptical antennae are up. You may be wondering how this digitization manifested in the measurements if it’s supposedly inaudible. That’s a legitimately good question, and the answer is simple. Per Diego:
There is extreme brickwall-type filtering at 20kHz, with a -3dB point at around 21.8kHz. There is a high probability that the analog input is digitized, because this type of brickwall filtering is easier to implement in the digital domain. Further evidence for this can be seen in the FFTs in this report. In the graph above and most of the graphs below, only a single trace may be visible. This is because the left channel (blue or purple trace) is performing identically to the right channel (red or green trace), and so they perfectly overlap, indicating that the two channels are ideally matched.
While difficult to see in this graph, we did find two peaks at 43.1kHz and 45.1kHz, which are telltale IMD products that are a result of the 1kHz analog signal being digitized and sampled at 44.1kHz.
The key thing to emphasize there isn’t merely the band-limiting, but the steep slope of the low-pass filter, which—given that the entirety of the slope is above the theoretical limits of human hearing—means it’s inaudible, assuming you’re a human being.
All of which is to say that, whatever you think about the HTA200, there’s absolute zero reason to object to its digitization of incoming analog signals. Mind you, I don’t see a ton to celebrate about that fact, either, at least not with regard to the Dayton Audio int-amp. It is value-neutral, best as I can see (and hear).
But the simple fact of that matter is that many of today’s best audio products do indeed benefit from operating, in part, in the digital domain, even with analog inputs. Firstly, and perhaps most obviously, digitization allows for products like NAD’s modern integrated amps to support Dirac Live room correction, which, in my humble opinion, is one of the most consequential features a modern stereo system can have.
I’ve written at times recently about how I needed a new reference integrated amp because my old one died completely to death. It came down to three choices for me, although I think in the past I may have fibbed by omission and painted it as a choice between two options. In reality, my shortlist included the Marantz Model 40n, the NAD C 3050, and an old Sansui G-6000 I fell in love with at my local record store.
There are any number of reasons the NAD C 3050 won out in the end, but one of them is the Dirac Live room correction, which requires digitization. Combine that with the old-school aesthetic and dancing-VU-meter charm of the C 3050’s design, and I couldn’t resist.
Another reason it won, though—and this may surprise some people—is the phono stage. And yes, I know I’ve said in the past that I’m just not into vinyl. But SoundStage! founder Doug Schneider has made a compelling case for why I need one, as a hi-fi reviewer, and I’m in the process of finding the right turntable for me right now. Thing is, I’m probably not getting one with a built-in phono pre, because I’ll mostly be using it to evaluate the phono stages of products I review. And I want a good baseline—one as close to neutral as you can possibly get in the world of vinyl without spending a king’s ransom.
Strike that. I need a good baseline. How do I know what a good, well-designed phono stage sounds like compared to others? There are a number of considerations, including impedance. But a big one is frequency response, and when I saw Diego’s measurements of the C 3050 LE’s MM input, I knew it was the baseline I wanted and needed.
If you can’t read the small text, by the way, it reads as follows: “The very strict adherence to the RIAA curve likely means that EQ is applied in the digital domain.”
I’m sure a certain vinyl guru (whose name I won’t invoke because he’s like Beetlejuice without the charisma) is digging his own grave so he can roll over in it as we speak. So be it. By contrast, here are frequency-response graphs of a number of fine phono stages measured by Diego that show what seems to be—to my eyes, anyway—typical of RIAA equalization done in the analog domain:
And let me be clear about something here: You might like the resulting sound of any or all of those phono stages. You may prefer them to the more neutral response of the digital RIAA EQ performed by the NAD. Don’t let anybody tell you that your preferences in that regard are wrong.
What I’m saying is that none of those are useful to me as a baseline for evaluating other phono stages. So, for me, give me digital or give me—well, no, just give me digital, please. Even with vinyl.
In fact, when I think back over some of my all-time favorite audio (and video) gear of the past two decades, almost all of it involved digitization of the analog inputs (although in many cases there was/is the option to bypass such). The Anthem Statement D2v 3D was, by a wide margin, the best A/V preamp to ever pass through my system, and if only it supported modern HDMI standards, it would still be in my home theater today. (In truth, it was a D2v that I converted to 3D spec by replacing the HDMI board myself, but you didn’t hear that from me.)
The thing about the D2v that not a lot of people bring up is that it sampled all incoming analog signals at 24-bit/96kHz and, if memory serves, resampled everything (even incoming digital signals) to 192kHz. Yet nobody in the world could question its audiophile bona fides.
Of course, it’s difficult to discuss the notion of digitizing analog audio and the perceptions of such without talking about the MoFi scandal from a few years back. Although Brent Butterworth and I podcasted about it, I didn’t write about it because I don’t have standing. I own like two dozen records, tops, and I think nine of them are still in the shrink wrap. And none of them were produced by or for Mobile Fidelity Sound Lab. Plus, who cares what I think about it when several of our own incredibly knowledgeable vinyl aficionados—namely Joseph Taylor (twice), Matt Bonaccio, and the inimitable Jason Thorpe—have already given much more informed and invested opinions than I could give.
I’ll just say this: I tend to agree with the overall SoundStage! consensus that what MoFi did wrong was not using a digital intermediate, but rather deceiving its customers into thinking there was no digital intermediate in its flagship releases by allowing this misconception to persist. But I think I might diverge from some of my esteemed colleagues in my estimation of exactly why that deception was so harmful. For me, it simply helped to perpetuate this notion that “analog = pure” and “digital = adulterated.” Which is a silly notion for any number of reasons.
I know somebody is going to call me out for hypocrisy here because I’m on record in any number of reviews expressing my love for albums that were recorded to tape. I also love the look of films shot on celluloid. But in both cases, I greatly prefer it when the original tapes or negatives are digitized as soon as humanly or Wookieely possible to avoid any of the degradation that comes from the playback of analog media.
Because that’s the thing about digital and analog: the former can capture all the nuances of the latter practically perfectly, but the latter cannot begin to emulate the perfect replicability of the former. (Say that three times fast.) So if you’re the type of person who’s prone to getting riled up when digital storage or signal processing are injected into what seems like (or purports to be) an otherwise analog signal chain, don’t. There’s nothing to get riled up about. Yes, MoFi lied to its customers, but its deception had no consequence on the sound quality of its records—merely their perceived value, given that their prices were assumed to reflect the wear-and-tear on the original master tapes, which were only touched once in reality, and the necessarily limited number of pressings, which it turns out were artificially limited.
Dayton Audio, NAD, Anthem, and others aren’t deceiving you at all, on the other hand. Nowhere in the product listing for the HTA200 does Dayton Audio claim that its signal chain doesn’t involve digitization. Yes, I could take issue with the marketing claim that its “amber-toned preamp tubes” result in “a warm sound,” which I called them out on in my review, months before I had any inkling that the analog inputs were being digitized.
My point is, there’s so much in audio that legitimately affects sound quality. As I’ve mentioned a bazillion times before, we don’t give enough attention to the impact of power supplies and volume controls on fidelity. But equally disturbing is that so many people in our hobby seem to obsess about things that don’t have any meaningful audible impact on fidelity.
But that’s a rant for another day, I suppose.
. . . Dennis Burger
dennisb@soundstagenetwork.com
