It’s natural to assume that a more expensive product is better than a cheaper one, which is why many people use the price tag to determine quality. If it sells for more, it must cost more to make, right? And that alone should make it superior. But with many products—hi-fi and otherwise—that’s simply not the case. Price can be a ruse.

I vividly recall how poorly made American cars were in the 1980s. Japanese manufacturers, whose cars were typically of superior quality, but oftentimes cheaper to buy, were able to gain a substantial leg up in the automobile market when people figured out that the price of a car didn’t correlate with build quality or reliability. Instead, the company’s reputation and the place of manufacture were better indicators of those things. In the late 1980s, I performed computer work for a high-end men’s clothing retailer. Sure, some of the very expensive clothes sold in the stores were better quality than what you’d find at the mass-market retailers—note that I used the word some—but what really drove the prices of those clothes so high were the brand names and the marketing campaigns that gave the impression of quality.

Doug Schneider

It’s long been the same for hi-fi components when it comes to listening impressions (the subjective part) and test-bench measurements (the objective aspect). For decades, it’s been relatively easy to find cheaper components that sound and/or measure as well as or better than more expensive ones. So that’s not news. But I’m writing this article today because I believe it’s become easier than ever to find relatively low-priced hi-fi components that kick the tails of very expensive ones for listening and measurements—if high transparency is sonically what you’re after. Among the many reasons for this are technical advancements that have pushed performance up and costs down.

Take the RME ADI-2 DAC FS digital-to-analog converter and NAD Masters M23 power amplifier as examples of what I’m talking about. The former, which Matt Bonaccio reviewed on this site last month, retails for $1299 (all prices in USD); the latter, which Roger Kanno has reviewed, but whose report hasn’t been published yet (look for it in the spring), sells for $3750.

These hi-fi components are not the cheapest you’ll find, but when it comes to producing utterly transparent sound, they’re both comparable to similar products at any price, which makes them a steal. Matt wrote in his review: “The ADI-2 stays out of the way of the music enough for you to forget it’s there—and that’s a wonderful thing.” As you’ll read when his review is published, Roger was bowled over by the clarity and lack of coloration of the NAD. There’s also one more SoundStager whose impressions can be added to the mix: S. Andrea Sundaram, who bought a Masters M23 last fall. When I began writing this article, I asked Andrea for his impressions of the amp so far. He wrote back: “Aside from the clarity with which it presents details and timbres, it’s the greater differences in character I hear between recordings that make me think the M23 is, itself, transparent. I also find myself playing music louder because it’s so clean.”


Corresponding with the way these products sound—or don’t sound, if it’s easier to think of it that way—is that they both perform extraordinarily well on the test bench. Furthermore, both are feature-rich for products of their types. But before we talk about the features, let’s talk about those measurements.

Analyzer-challenging measurements

We believe that our electronics measurement specialist, Diego Estan, produces the most exhaustive sets of measurements in the entire hi-fi-publishing world. As a result, I won’t even attempt to recount everything he’s measured on these products because I could go on forever. But I’ll point out a few highlights for each product.


When Diego tested the ultra-compact ADI-2 DAC FS, it exhibited less than 0.00006% total harmonic distortion (THD) from the left channel and less than 0.00005% THD from the right channel through its balanced outputs when fed with a 0dBFS, 24-bit/96kHz digital signal at 1kHz (both THD figures unweighted). With noise added in (i.e., THD+N, A-weighted), the figures rose to just 0.0001% for both channels. These percentages are incredibly low. The crosstalk figures at 10kHz were just as noteworthy: -129.2dB and -150.5dB for the left and right channels, respectively. The results for the J-Test jitter-immunity tests were exceptional as well, with the ADI-2 performing pretty much flawlessly when fed digital signals through its S/PDIF inputs, even when 500ns of analyzer-induced jitter was added to the test signal.

As impressive as these measurements are, it was when we got into a bit of back-and-forth with RME Audio cofounder Matthias Carstens that I knew we were dealing with a topflight, exceptionally well-engineered piece of kit. That back-and-forth happened because the signal-to-noise ratio (SNR) we measured from the ADI-2’s in-ear monitor (IEM) headphone output didn’t quite match RME’s spec. Diego got 116dB, which is still excellent, but 5dB worse than RME’s supplied figure of 121dB (A-weighted, referenced to 0.5Vrms).


Carstens correctly pointed out that our figure was limited by the noise floor of the Audio Precision APx555 B Series analyzer we use, which Diego knew could be the case when he was measuring the ADI-2 DAC FS. Think about that for a second—the device under test (DUT) couldn’t be evaluated properly by a state-of-the-art test analyzer like the APx555 because the DUT’s noise level was at a comparable or lower level than the analyzer. Consequently, we noted the issue with an asterisk in our report of the measurements. But the real takeaway from this is that the distortion and noise the ADI-2 DAC FS produces—almost none—challenges the limits of even a top-drawer test setup like ours. Go check the full suite of measurements, which are not only impressive for the DUT’s price, but for gear of any price.

Much the same can be said about the M23, which uses class-D amplifier technology and a switching power supply, as opposed to the class-AB or class-A topology of a traditional amplifier design, which would likely have a linear power supply. The M23 is a power amplifier that most buyers will use as a stereo amplifier, but can be bridged for mono operation. In either case, the M23 met or exceeded NAD’s own claims in all performance parameters, including power output.


As a stereo amp, NAD claims the M23 outputs at least 210Wpc into 8 ohms with less than 0.1% THD. We haven’t published the measurements yet, but Diego squeezed out 229Wpc before the 0.1% threshold was hit. In mono, NAD claims more than 770W with less than 0.1% THD—we got 862W. We also exceeded NAD’s 4-ohm and dynamic-power specs as well. Insofar as power output goes, you can consider the M23 conservatively rated by the manufacturer. What’s more, it remained stable—and with very low distortion—into a 2-ohm load when operated in stereo mode. (It’s not suitable for 2-ohm loads as a monoblock, which is typical of bridged designs.) As a stereo amp in particular, it should drive pretty much any loudspeaker out there—cleanly.

Of course, few people will tap the M23’s full power all the time, but that doesn’t matter, because it’s at lower output levels that the M23 truly shines. At 10Wpc output into 8 or 4 ohms in stereo mode (with its back-panel Gain Level switch set to Mid, something I’ll explain later), the M23’s THD hovered around 0.00008% into 4 ohms and 0.00005% into 8 ohms. Both are extraordinarily low figures—lower, in fact, than any traditional class-A or class-AB amp we’ve seen, at any price. With noise considered (10Hz to 22.4kHz bandwidth), the 8- and 4-ohm figures stayed below 0.0005%. Intermodulation distortion figures were just as low—and, therefore, just as noteworthy.

Lotsa features

As I mentioned, the M23 can be used as a stereo amp or monoblock. The changeover is done by flicking a switch on the back panel, which is handy. But also on the back panel is the Gain Level switch that I mentioned earlier. It has three positions: Low, Mid, High. These can be set to adjust the amp’s gain to account for the gain of a connected source component, to optimize the noise performance of the pairing. For example, if you have a high-gain preamp, you might want to use the lowest gain setting on the amp. Conversely, if your preamp has lower-than-normal gain, more gain on the amp might be needed. The M23 also has a 12V trigger input for auto turn-on, as well as both single-ended (RCA) and balanced (XLR) inputs.


The RME ADI-2 DAC FS has such a rich feature set that I don’t want to get into it here for the same reason I didn’t want to go through all the measurements—you should just read Matt’s review. But I will say that it’s way more than just a DAC—for instance, the DAC section alone has six user-adjustable filters; S/PDIF optical (TosLink), S/PDIF coaxial (RCA), USB, and Bluetooth digital inputs; and support for DSD playback as well as PCM playback up to 768kHz.

The ADI-2 DAC FS also has two headphone outputs, including the specialized IEM one I mentioned (the other is high output over a standard 1/4″ jack); single-ended (RCA) and balanced (XLR) outputs; a digital volume control coupled with an unusually high, user-selectable maximum output voltage of 10Vrms, meaning it can be plugged directly into any power amplifier imaginable and drive it to full power; a remote control; and a host of other features accessible through the front-panel menu system. But that just skims the surface, which is why Matt wrote in his review that the ADI-2 is “an astoundingly versatile DAC, one that represents a great value in its price class and beyond.” Nuff said.

The takeaway

The point of this article isn’t to review the ADI-2 DAC FS and Masters M23; instead, it’s to highlight something that benefits you, the consumer: these days, price is one of the last things you should use to determine a component’s performance. These are two examples, but there are many more.

So what should you do when evaluating a product? As always, use your ears to guide you, regardless of the price tag. You should also put some faith in what the measurements say, which, if the product performs as well as RME’s ADI-2 DAC FS or NAD’s Masters M23, can be as eye-opening as these products are ear-opening. If you do these things, you’ll end up making a much better purchase decision—and you might end up with an affordable system that’s more transparent-sounding and with better resolution than one that takes all the money in the world to buy.

. . . Doug Schneider