HiFi Rose RS250 audio & video streaming D/A preamplifier The RS250A

John Atkinson reviewed the HiFi Rose RS250A in October 2023 (Vol.46 No.10):

Although I reviewed the original version of this elegant South Korean streamer not too long ago, in the December 2021 issue, it has already been updated. The RS250A ($2695, footnote 1) replaces the RS250's ESS ES9038Q2M two-channel DAC chip with the higher-performance ESS Sabre ES9028PRO chip and now supports PCM data formats up to 32/768 and DSD formats up to DSD512.

MoFi Distribution sent me a sample of the new RS250A. I installed the Rose HIFI app on my iPad mini and connected the RS250A to my NetGear router. My sample had serial number EBK211AB000173 and, according to the Rose app's Device Management page, was running operating system version 4.5.05, which updated to v4.6.06 as I was writing these words. The Rose app identified the RS250A as "ROSE-79." Roon recognized the RS250A as a full MQA decoder and renderer and noted that it handles 32-bit PCM data with a maximum sample rate of 768kHz.

To audition the RS250A, I connected its single-ended analog outputs to the CH Precision I1 Universal integrated amplifier, which I reviewed in the August 2023 issue. The I1 was set to Bypass mode, where it behaves as an all-analog, fixed-gain power amplifier. Loudspeakers were KEF LS50 minimonitors, sitting on 24" stands and connected to the amplifier with 10' lengths of AudioQuest Robin Hood cable. I used Roon to control volume and its parametric equalization function to extend the LS50s' low frequencies.

With the original RS250 long since returned to MoFi Distribution, comparisons between it and the new version weren't possible. But using Roon and the network connection, I played some of the same files I had used to reach my original conclusions about the streamer's sound quality: Jerome Harris's Rendezvous album (16/44.1 ALAC, Stereophile STPH013-2), which I engineered and mixed; Sasha Matson's Molto Molto jazz-orchestra album (24/96 WAV, Stereophile STPH024), which I produced; and Daft Punk's "Lose Yourself to Dance," from Random Access Memories (24/88.2 ALAC, Columbia/HDtracks), which I neither engineered nor produced but which gets me losing myself and dancing every time I hear it.

The results? I still preferred the "Corrected minimum phase Fast Roll-off " reconstruction filter for the ease of its sound. I still found the soundstaging precise, coupled with excellent transparency to recorded detail. However, as with the original model, kickdrum sounded a little tubby and bass guitar had slightly too much upper-bass bloom. This will be due in part to the CH Precision amplifier, which also has a touch of that character when set to 40% global negative feedback, which was how I had it set. Changing to the MBL N31 processor as the source tightened up the lows compared with the HiFi Rose.

After returning the CH Precision to the distributor, I continued my audition using first a pair of Parasound Halo JC 1+ monoblocks then the Audio Research I/50 integrated amplifier, which I reviewed in the September 2023 issue. My experience with these two very different amplifiers was as positive as it had been with the CH Precision. There's little more to say about the experience.

The RS250 offered excellent measured performance for a relatively inexpensive, full-functioned product, with very low harmonic and intermodulation distortion and digital resolution of better than 19 bits. The only somewhat disappointing results I noted were the analog input's relatively low input impedance of 3.3k ohms, which might make the low frequencies sound a little lightweight with tubed source components, and some random-noise–related jitter.

I ran some of the same tests on the HiFi Rose RS250A with my Audio Precision SYS2722 system. The analog input impedance was essentially the same, a relatively low 3.2k ohms; the analog output impedance was 146 ohms, higher than the original's 100 ohms but still usefully low.

Fig.1 HiFi Rose RS250A, CMPFR filter, impulse response (one sample at 0dBFS, 44.1kHz sampling, 4ms time window).

Unlike the earlier version, the RS250A inverted absolute polarity for both analog and digital inputs. This can be seen in fig.1, which shows the impulse response with 44.1kHz-sampled Ethernet data and the default "Corrected minimum phase Fast Roll-off " (CMPFR) reconstruction filter.

Fig.2 HiFi Rose RS250A, CMPFR filter, wideband spectrum of white noise at –4dBFS (left channel red, right magenta) and 19.1kHz tone at 0dBFS (left blue, right cyan) into 100k ohms with data sampled at 44.1kHz (20dB/vertical div.).

Like the original RS250 and the RS520 integrated amplifier reviewed by RvB in the July 2023 issue, the RS250A offers a choice of seven filters, labeled "Brick Wall" (BW), "Apodizing Fast Roll- off " (AFR), "Minimum phase Slow Roll-off " (MPSR), "Minimum phase Fast Roll-off " (MPFR),"Linear phase Slow Roll-off" (LPSR), and "Linear phase Fast Roll-off " (LPFR)." In the frequency domain, these filters all behave identically to those in the other HiFi Rose products. Fig.2, for example, which was measured with the CMPFR filter, shows the response up to 100kHz with 44.1kHz-sampled white-noise data (magenta and red traces) and the spectrum with a full-scale tone at 19.1kHz (cyan, blue).

Fig.3 HiFi Rose RS250A, 24-bit data, spectrum of 1kHz sinewave, DC–1kHz, at 0dBFS into 100k ohms (left channel blue, right red; linear frequency scale).

Fig.4 HiFi Rose RS250A, spectrum with noise and spuriae of dithered 1kHz tone at –90dBFS with: 16-bit Ethernet data (left channel cyan, right magenta), 24-bit Ethernet data (left blue, right red) (20dB/vertical div.).

While the RS250's low-frequency noisefloor with the network connection was disturbed by some low-level AC supply–related spuriae, the RS250A's noisefloor was clean (fig.3). Other than a slight rise in the level of random noise between 6kHz and 9kHz, an increase in bit depth from 16 to 24, with network data representing a dithered 1kHz tone at –90dBFS sourced from Roon, dropped the RS250A's noisefloor by almost 30dB (fig.4). This graph implies a resolution of close to 21 bits, superb performance for an affordable processor.

Fig.5 HiFi Rose RS250A, high-resolution jitter spectrum of analog output signal, 11.025kHz at –6dBFS, sampled at 44.1kHz with LSB toggled at 229Hz: 16-bit Ethernet data (left channel blue, right red). Center frequency of trace, 11.025kHz; frequency range, ±3.5kHz.

Fig.5 shows the spectrum of the RS250A's output when it was fed high-level, 16-bit J-Test data. In contrast to the original RS250, which boosted the levels of the pair of sidebands surrounding the high-level tone at one-quarter the sample rate (footnote 2), all the odd-order harmonics of the undithered low-frequency, LSB-level squarewave lie at the correct levels, indicated by the sloping green line in this graph. However, the noisefloor still rises in level on either side of the high-level tone, and a pair of sidebands of unknown origin is now present at ±880Hz.

Summing Up
I wrote in my review of the original RS250 that it was "an extraordinarily versatile, affordable product" and that its sound quality suggested that nothing had been compromised in packing so many features into its small chassis. "Highly recommended," I concluded, "both as a streaming DAC and as an all-in-one hub for a high-end audio system." With this audition, I extend that recommendation to the new RS250A. It is an elegant-looking, well-engineered, multipurpose component.—John Atkinson

Footnote 1: HiFi Rose, 11F, 932 Yangjae-daero, Songpa-gu, Seoul, South Korea. Tel: 82-1899-6042. Web: hifiroseUSA.com. US distributor: MoFi Distribution, 1811 W. Bryn Mawr Ave., Chicago, IL 60660. Tel: (312) 841-4087. Web: mofidistribution.com.

Footnote 2: See fig.14 here.

HiFi Rose
US distributor: MoFi Distribution
1811 W. Bryn Mawr Ave.
Chicago, IL 60660
(312) 841-4087

Axiom05's picture

Well, the jitter spectrum of the QB-9 Twenty looks good at least. I really should get my QB-9 DSD upgraded.

CG's picture

Good catch!

That's probably the review of the QB-9 Twenty in its entirety. After all, the Twenty is an upgrade to a no longer manufactured product.

And, yeah, you should get the upgrade. At the risk of sounding like a shill for Ayre, the upgrade is really worth the asking price, and probably a lot more. (Which I paid in full - if I'm a shill, I'm also a very bad negotiator.)

Axiom05's picture

I just upgraded the USB board in my QX-5 Twenty and WOW, I was not expecting this kind of improvement. Definitely a worthwhile upgrade. I guess we're both shills for Ayre. :-)

CG's picture

I can see why.

Compare Figure 16 to the comparable plot in the Stereophile review for the original QX-5 Twenty.

Of course, many, many people will tell you that this sort of thing is inaudible and that you are crazy. But, crazy people can be happy, too.

Jack L's picture


When one crazy enough to burn his/her easy money to be happy, why not ?

Life is short so make the best use of it.

Jacl L

CG's picture

Somewhat OT:

This seems as good a place to ask this as any.

This particular digital solution seems to perform not quite as well as some other products with regard to jitter sidebands. Is this audible? By how much? Why?

Now... Head to the bottom of this very web page and click on the button that says "hi-finews". That'll take you to a website for the magazine of the same name.

Look at a turntable review. Any turntable review.

In the Lab Report, there is a plot of what is labeled Wow and flutter. This is a spectral display of a single tone from a vinyl disc played back through the turntable under review.

Isn't that pretty much the same concept as the jitter test, at least with regard to the central tone of the J-test at 11 KHz?

So, how is one to interpret all of this? One is obviously far different than the other.

It's not obvious from either plot and associated labelling what the measurement parameters are for the spectrum analyzer. The resolution bandwidth, the video filtering, the averaging type and number of samples, the detector type, and so on are not shown for either. (To be fair, this might be explained in an article somewhere that I failed to find - my bad.) Variations there would explain a lot. But, maybe there's much more to it.

I find this all confusing. Perhaps I am the only one who does, though.

Perhaps I am overthinking all of this, too. Wouldn't be the first time.

Archimago's picture

I don't think there's much confusion here. Jitter was never all that audible as an issue. No need for audiophiles to fear this "boogeyman" in general. I posted a demo for folks to listen to years ago - just Google "Archimago Jitter Demo".

Yeah, the J-Test for a device like this is not good for modern 2021 digital especially for the 24-bit ethernet input. I still don't think it's audible in real music anyways, it's more of a reflection of the engineering that the time-domain wasn't better despite the claims of using femtoclock parts and the ESS ES9038Q2M DAC chip!

No surprise as well that turntables are comparatively inaccurate vs. digital (Google "Archimago vinyl LP fidelity" for a discussion). It's very obvious if one listens to a pure tone like 3150Hz as per HiFi News. Time-domain is poor with LP playback not just because of turntable rpm variations but also the imperfections of the vinyl itself. Again, with music we don't notice these issues as much.

BluesDog's picture

Nice article. Thanks for testing storage drives (i.e. usb thumb drive, portable HDD, etc) on this device Some of us have amassed significant size CD quality or better on storage drives. From the late 90’s and before streaming had the quality we see tday. Streaming Qobuz and Tidal are impressive but some of us aren’t quite ready to pay for yet another streaming subscription. Articles like yours (and the use of Roon) help prepare us for if that plunge ever comes.

Jack L's picture


If only HD music videos are needed (what else??), I would not bother to spend my nerves & hard-earned cash on those bells & whistles loaded 'hi-tech' streamers.

Yes, YouTube provides 24/7 tons HD & 4KUHD music shows, streamable FREE by any WiFi HD & 4KUDH blue-ray players. Let's lead a simple life & enjoy really
eye-widening & ear-thrilling HD/4KUHD music shows on our 4KUHD TVs streamed free from YouRTube. Who needs to sweat fighting with those complex 'hi-teck' remotes ???

This is exactly what yours truly have been doing since a couple years back. I simply feed the digital PCM audio signals from the coaxial O/P jack of the HD Blu-ray player to my 24bit/192KHz DAC which in turn hooked up to the linestage I/P of my design/built tube phono-preamp with its PASSIVE bypass switched on. So the HD audio signals from the DAC electrically feeds direct to the power amp !

Please note any DACs deliver adequate output voltage to drive directly any power amps to their rated full output power. Or simply feed the DAC L/R analogue audio signals direct into the power amp if it comes with built-in volume controls. The sonic is sooo rewarding..

With such DIRECT signal feed to the power amp, the HD sonic quality of so many those HD/4KUHD music shows from YouTube becomes surprisingly sooo good to make my skeptical vinyl-addicted ears up-pointing !! No kidding.

Life is short so let's make it simple.

Listening is believing

Jack L

franz2022's picture

The one year warranty from a new company is a disappointment. At a minimum it should be two years. The NAD M10 and Cambridge Audio EVO 150 are covered for three years. I've had far too many expensive electronics fail within three years of ownership. HP replaced a 4K monitor that stopped working unexpectedly after two years (covered for 3) while I was out $2k when my Noble Audio IEMs failed shortly exceeding their warranty period.