[ku1185]

Well I guess this is burn-in, but I put these on today and surprised to find it sounds significantly better than couple of days ago. I think it might've been in one of those "regressive states" last I listened. I have this connected to the soloist 3xp alongside the Ares II, volume matched (with decibel meter), and both simultaneously fed by Douk u2 pro. All I need to do is press the input button on 3xp remote to instantly switch between the two DACs.

Flipping between the two, there are fewer noticeable deficiencies in the r2r-11. Hardness is gone and there's better texture to percussions and air in vocals. Imaging, separation, and stage have improved. I hear much more nuance and it's musical. I don't get an urge to flip back to the Ares II. Simply put, I'm finding it more enjoyable, even alongside the Ares II where it's 1 button push away.

Only disappointment is that I still have about 2 more weeks or burn-in until I hit the 500 hour mark. And I'll be leaving for a trip right when I hit that mark too =(.

Side note, maybe better for Ares thread: the latency on Ares is wonky. Sometimes there's no noticeable latency and there's no break in continuity when switching inputs. Then, sometimes, there is. Switching tracks, pausing tracks, and changing filters on Ares, sometimes introduces or eliminates the latency. Sometimes it doesn't.

 

[sajunky]

Side note, maybe better for Ares thread: the latency on Ares is wonky. Sometimes there's no noticeable latency and there's no break in continuity when switching inputs. Then, sometimes, there is. Switching tracks, pausing tracks, and changing filters on Ares, sometimes introduces or eliminates the latency. Sometimes it doesn't.

Yes, latency on Ares is variable (using a large circular buffer for reclocking) and there is no cure. R2R-11 has a minimum latency, the same the upper models. Asynchronous USB transfers allow jitter-free data delivery, there is no need for reclocking.

 

[dougms3]

Well I guess this is burn-in, but I put these on today and surprised to find it sounds significantly better than couple of days ago. I think it might've been in one of those "regressive states" last I listened. I have this connected to the soloist 3xp alongside the Ares II, volume matched (with decibel meter), and both simultaneously fed by Douk u2 pro. All I need to do is press the input button on 3xp remote to instantly switch between the two DACs.

Flipping between the two, there are fewer noticeable deficiencies in the r2r-11. Hardness is gone and there's better texture to percussions and air in vocals. Imaging, separation, and stage have improved. I hear much more nuance and it's musical. I don't get an urge to flip back to the Ares II. Simply put, I'm finding it more enjoyable, even alongside the Ares II where it's 1 button push away.

Only disappointment is that I still have about 2 more weeks or burn-in until I hit the 500 hour mark. And I'll be leaving for a trip right when I hit that mark too =(.

Side note, maybe better for Ares thread: the latency on Ares is wonky. Sometimes there's no noticeable latency and there's no break in continuity when switching inputs. Then, sometimes, there is. Switching tracks, pausing tracks, and changing filters on Ares, sometimes introduces or eliminates the latency. Sometimes it doesn't.

I've been experiencing the same thing with the Ares. The latency is really weird, randomly it will pause the music to buffer. Not a big deal, since it only happens here and there maybe once or twice a day.

How does the r2r 11 compare to the ares? Is it more of a lateral step or overall increase in sound quality?

 

[ku1185]

I've been experiencing the same thing with the Ares. The latency is really weird, randomly it will pause the music to buffer. Not a big deal, since it only happens here and there maybe once or twice a day.

How does the r2r 11 compare to the ares? Is it more of a lateral step or overall increase in sound quality?

I'm still in the burn in period, so I'm hesitant to say. R2R-11 sounds noticeably better after just over a week of burning in, and I expect it may change further.

That said, so far my takeaway is that it's just a different presentation. There are a few things about the Ares II that sounds uncanny to me: plasticky treble, weird staging (all empty "space" filled with resonance/reverberations, imaging feels "stretched out," etc.). But I love listening to music on it. The r2r-11 is more akin to the AKM dacs that I'm used to (while Ares reminds me more of ESS dacs' lightweight and "delicate" touch to sounds). More space in between notes, more punch, more weight, and smoother/cleaner sounding, all while with barely any detectable glare/harshness. I thought the D1se was smooth but so far the r2r-11 sounds smoother. I think the Ares II has a touch of that glare/harshness/sibilance, but really not bad at all as it's never presented with a lot of intensity.

I'll probably have more firm opinions in a few weeks, but so far it seems more a lateral step. I'd tentatively say the Ares II sounds technically more impressive due to all the low levels sounds (resonance, reverb, timbre) that it seems to bring out of the music. I do think that the r2r-11 mk2 is better value though. Fewer inputs/outputs, but you get a pretty nice headamp and the preamp is actually really nice on the r2r-11. Works really well with soloist 3xp in poweramp mode (didn't have good experience using D1se or SA-1 as preamp).

 

[Pharmaboy]

I'm still in the burn in period, so I'm hesitant to say. R2R-11 sounds noticeably better after just over a week of burning in, and I expect it may change further.

That said, so far my takeaway is that it's just a different presentation. There are a few things about the Ares II that sounds uncanny to me: plasticky treble, weird staging (all empty "space" filled with resonance/reverberations, imaging feels "stretched out," etc.). But I love listening to music on it. The r2r-11 is more akin to the AKM dacs that I'm used to (while Ares reminds me more of ESS dacs' lightweight and "delicate" touch to sounds). More space in between notes, more punch, more weight, and smoother/cleaner sounding, all while with barely any detectable glare/harshness. I thought the D1se was smooth but so far the r2r-11 sounds smoother. I think the Ares II has a touch of that glare/harshness/sibilance, but really not bad at all as it's never presented with a lot of intensity.

I'll probably have more firm opinions in a few weeks, but so far it seems more a lateral step. I'd tentatively say the Ares II sounds technically more impressive due to all the low levels sounds (resonance, reverb, timbre) that it seems to bring out of the music. I do think that the r2r-11 mk2 is better value though. Fewer inputs/outputs, but you get a pretty nice headamp and the preamp is actually really nice on the r2r-11. Works really well with soloist 3xp in poweramp mode (didn't have good experience using D1se or SA-1 as preamp).

I've never heard an Ares II so can't comment, beyond saying the R2R-11 MKII & Ares II are roughly equivalent pricewise, if you opt for the upgraded USB board in the R2R (I did not).

After burning mine in 500+ hours and listening to it in both systems w/all my headphones as well as speakers, I concluded several things:

• This is relatively neutral but still satisfyingly musical NOS DAC. The sound betters most delta-sigma I've heard.
  • I just became aware of the possibility of adding 2 jumpers to make the sound warmer. I'll check that out, but am not expecting it will transform this DAC into a $30K audiophile special. And I'm OK with that.
• I never used the amp portion (don't need that), but my experience w/past AGD amps is they're powerful, slightly warm, and quite dynamic: good middle-of-the-road single ended SS amping
• For my purposes, the preamp capability is the most meaningful design feature, beyond NOS itself. I find it very handy to use the volume pot to adjust system gain, while controlling actual volume at the external HP amp

All in all, it's a well designed, completent/useful, and good sounding NOS DAC at a reasonable price. It checks all the boxes for me and I'm quite happy with it.

 

[ku1185]

So I've spent a month with the R2R-11 Mk2 with upgraded USB, alongside Ares II and Soloist 3xp. I've used the r2r-11 with its USB in and HP out, and I've also had both DACs fed by Douk U2 Pro and both DACs going into 3xp. They were volume matched and used remote to seamlessly switch between the DACs on the 3xp.

Intro/tl;dr
Fell in love with Ares II in "NOS" mode. Started looking for some other NOS DACs to try and stumbled on the r2r-11 mk2. r2r-11 is a very nice sounding unit. More neutral sounding than I had expected, though just a touch warmer/darker/veiled compared to Ares II (and JDS El Stack II). I don't notice when enjoying music, and generally I'd say this is tonally neutral and uncolored. For casual listening at my desk, I much prefer the r2r-11 over Ares II, surprisingly.

DAC Sound
Very full bodied, smooth, and a bit forward presentation to sounds. Good sense of weight and presence, while doing a good job bringing out those subtle nuances/microdynamics that, combined with that weightiness, makes for engaging and enjoyable listening. I can just feel the music better, particularly in the vocals. Ares II, while beautifully detailed, has a more reserved and laid-back presentation. Sounds don't have as much presence and often feels like it's lacking gusto. r2r-11 is more gripping, yet never feels overwhelming or fatiguing. It's very forgiving of poorly recorded music. I've been really digging 80's music and R&B since I've got this, but works very well with just about all genres methinks.

Staging is fair. Not as interesting as Ares II or OG BF2, but I prefer this over other D/S DACs I've had (D1se, El Dac II, Topping E30, K5 Pro, various dongles). Perhaps lacking some spatial cues, and feels a little like sounds are coming from the void. Separation, imaging, layering are all decent, but behind the Ares II (and probably BF2 as well, as it had the best staging of DACs I've owned). Seems slightly improved with oversampling.

Dynamics get full marks from me. More power and energy than Ares II, and more controlled and nuanced than OG BF2. And it's worth repeating that the subtle nuances in dynamics are nicely captured in the full bodiedness and weightiness of the sounds. Brings that weight and dynamics to the forefront which helps to nicely convey the phrasing in the music. The two aforementioned DACs do it too, but seems to plays a bigger role in r2r-11's defining sound characteristics, at least in my mind. The Ares II is probably better in this regard, but it's more upfront and center with the r2r-11.

There's nothing to the sound that's so uncomfortable or lacking that I feel it interferes with enjoyment of music. No harshness, no awkward timbre, no congestion.

Build and Misc.
Built fairly nice, actually. Doesn't look nearly as bad as I'd thought it might. I kinda admire the industrial look to it. Really big, but taking off the hood and seeing the guts is cool. Wish it had more inputs/outputs. Volume knob is stepped, and hearing the relays clicking is cool. The volume control is great overall, and have no issues with sensitive headphones like LCD-X (which I can't say for SA-1 or JDS El Amp due to channel imbalance at low levels).

Burn in was a bitch. Sound quality was all over the place and took ~2 weeks before DAC started settling in. The USB input took additional week or two to settle in but it sounds fairly good now. Sounded good through U2 Pro via coax and SPDIF too, but r2r-11's coax input does not do 176khz, and SPDIF only goes to 96khz. Bummed, but at least it's stated as such on their webpage. Oversampling seems to make a more noticeable difference to the sound than other DACs I've messed around with.

Preamp works great. Allowed me to volume match with Ares II. Moreover, I was very pleased using the r2r-11's preamp and 3xp's poweramp mode. I didn't have good results with SMSL D1se or Singxer SA-1's preamp, but the r2r-11 was good even at low levels (~5-8/100). Feel like I've now a much better idea of 3xp's potential.

The headamp section of the r2r-11 is very adequate. Very smooth sounding, but feels a bit pushed up against me. Sounds feel more forward and stage feels tightly packed (but not congested) and flatter. Feels less "open" or spacious over the 3xp or even El Amp II. But otherwise, I think the amp sounds smooth, refined, and fairly good overall. Vaguely reminiscent of Jot2's balanced out in presentation but smoother, and maybe less depth.

I've not had any issues with popping noises. It's rarely there when changing tracks, and usually barely audible. Audio-GD's website does warn users of such noises, however, so YMMV.

Warm sound jumper is a pain in the ass to get to. Have to open up the unit and snake your fingers onto the jumper. Easy once I got the hang of it, but annoying and time-consuming nonetheless. With the jumper, sound is much warmer/darker, maybe a little thicker, a little softer. Preferred it with DT770 and HD600, but lose too much upper mids/treble for the LCD-X and HD58x, causing sounds to feel a bit muffled.

Closing thoughts
This is perfect for my desk for casual listening while gaming, lurking forums, etc. Wish I'd found something like this a year ago right after I had the OG BF2. Shame that these aren't more popular here in the West. At this point, I'm starting to wish I'd gone for something like the R28. If only I had the space...

 

[Pharmaboy]

So I've spent a month with the R2R-11 Mk2 with upgraded USB, alongside Ares II and Soloist 3xp. I've used the r2r-11 with its USB in and HP out, and I've also had both DACs fed by Douk U2 Pro and both DACs going into 3xp. They were volume matched and used remote to seamlessly switch between the DACs on the 3xp.

Intro/tl;dr
Fell in love with Ares II in "NOS" mode. Started looking for some other NOS DACs to try and stumbled on the r2r-11 mk2. r2r-11 is a very nice sounding unit. More neutral sounding than I had expected, though just a touch warmer/darker/veiled compared to Ares II (and JDS El Stack II). I don't notice when enjoying music, and generally I'd say this is tonally neutral and uncolored. For casual listening at my desk, I much prefer the r2r-11 over Ares II, surprisingly.

DAC Sound
Very full bodied, smooth, and a bit forward presentation to sounds. Good sense of weight and does a good job bringing out those subtle nuances/microdynamics that, combined with that weightiness, makes for engaging and enjoyable listening. I can just feel the music better, particularly in the vocals. Ares II, while beautifully detailed, sounds more reserved and laid-back. Sounds don't have as much presence and often feels like it's lacking gusto. r2r-11 is more gripping, yet never feels overwhelming or fatiguing. It's very forgiving of poorly recorded music. I've been really digging 80's music and R&B since I've got this, but works very well with just about all genres methinks.

Staging is fair. Not as good as Ares II or OG BF2, but I prefer this over other D/S DACs I've had (D1se, El Dac II, Topping E30, K5 Pro, various dongles). Perhaps lacking some spatial cues, and feels a little like sounds are coming from the void. Separation, imaging, layering are all decent, but behind the Ares II (and probably BF2 as well, as it had the best staging of DACs I've owned). Seems slightly improved with oversampling.

Dynamics get full marks from me. More power and energy than Ares II, and more controlled and nuanced than OG BF2. And it's worth repeating that the subtle nuances in dynamics are nicely captured in the full bodiedness and weightiness of the sounds. Brings that weight and dynamics to the forefront which helps to nicely convey the phrasing in the music. The two aforementioned DACs do it too, but seems to plays a bigger role in r2r-11's defining sound characteristics, at least in my mind.

There's nothing to the sound that's so uncomfortable or lacking that I feel it interferes with enjoyment of music. No harshness, no awkward timbre, no congestion.

Build and Misc.
Built fairly nice, actually. Doesn't look nearly as bad as I'd thought it might. I kinda admire the industrial look to it. Really big, but taking off the hood and seeing the guts is cool. Wish it had more inputs/outputs. Volume knob is stepped, and hearing the relays clicking is cool. The volume control is great overall, and have no issues with sensitive headphones like LCD-X (which I can't say for SA-1 or JDS El Amp due to channel imbalance at low levels).

Burn in was a bitch. Sound quality was all over the place and took ~2 weeks before DAC started settling in. The USB input took additional week or two to settle in but it sounds fairly good now. Sounded good through U2 Pro via coax and SPDIF too, but r2r-11's coax input does not do 176khz, and SPDIF only goes to 96khz. Bummed, but at least it's listed on their webpage. Oversampling seems to make a more noticeable difference to the sound than other DACs I've messed around with.

Preamp works great. Allowed me to volume match with Ares II. Moreover, I was very pleased using the r2r-11's preamp and 3xp's poweramp mode. I didn't have good results with SMSL D1se or Singxer SA-1's preamp, but the r2r-11 was good even at low levels (~5-8/100). Feel like I've now a much better idea of 3xp's potential.

The headamp section of the r2r-11 is very adequate. Very smooth sounding, but feels a bit pushed up against me. Sounds feel more forward and stage feels tightly packed (but not congested) and flatter. Feels less "open" or spacious over the 3xp or even El Amp II. But otherwise, I think the amp sounds smooth, refined, and fairly good overall. Vaguely reminiscent of Jot2's balanced out in presentation but smoother, and maybe less depth.

I've not had any issues with popping noises. It's rarely there when changing tracks, and usually barely audible. Audio-GD's website does warn users of such noises, however, so YMMV.

Warm sound jumper is a pain in the ass to get to. Have to open up the unit and snake your fingers onto the jumper. Easy once I got the hang of it, but annoying and time-consuming nonetheless. With the jumper, sound is much warmer/darker, maybe a little thicker, a little softer. Preferred it with DT770 and HD600, but lose too much upper mids/treble for the LCD-X and HD58x, causing sounds to feel a bit muffled.

Closing thoughts
This is perfect for my desk for casual listening while gaming, lurking forums, etc. Wish I'd found something like this a year ago right after I had the OG BF2. Shame that these aren't more popular here in the West. At this point, I'm starting to wish I'd gone for something like the R28. If only I had the space...

Thank you for these cogent & well-expressed perceptions of the R2R-11 MK2.

I use mine in my side-system (headphones only). Because I asked AGD to add a 2nd RCA output to the back, I typically hear any given headphone on 2 amps being fed the DAC output of this unit. And I agree with all your comments. This is NOS voiced to be relatively neutral. You don't run into that every day.

This unit is also a terrific preamp. I need a transparent volume control on the DAC in this system, and that's what this unit has. It allows me to reduce the gain by 25% to put both amps' volume controls in their "sweet spot."

 

[sajunky]

Sounded good through U2 Pro via coax and SPDIF too, but r2r-11's coax input does not do 176khz, and SPDIF only goes to 96khz

My U2 Pro also doesn't play 176kHz, but it does play 192kHz, see my comment on the Poorman DDC thread. It looks to me a faulty XMOS chip, as all other 44.1kHz family sample rates have a slight, but noticeable jitter, while 176k gives a noise. It looks like we got the same batch of a faulty chip.

 

[ku1185]

My U2 Pro also doesn't play 176kHz, but it does play 192kHz, see my comment on the Poorman DDC thread. It looks to me a faulty XMOS chip, as all other 44.1kHz family sample rates have a slight, but noticeable jitter, while 176k gives a noise. It looks like we got the same batch of a faulty chip.

Interesting. It works fine at 176khz through the Ares II.

Do you have one of the upgraded clocks version?

 

[sajunky]

Interesting. It works fine at 176khz through the Ares II.

Do you have one of the upgraded clocks version?

Not. Replaced on U2 Pro oscilator 44.1kHz family the same grade, hoping it will fix the issue, but no changes. I planned to do, but in this situation there was no reason upgrading oscilators on U2 Pro. My R2R-11 is early version, not mk2 as yours, no correlation.

[Edit] If you meant upgrading oscilators on R2R-11, then yes, it is already DIY upgraded to the Crystek fem-to second oscilators.

Nice review, I agree all around.

 

[Dailydrive]

I'm a cheapstake in this hobby, with budget DACs in 11.38 ('18) & R2R11mk1 ('19) & DEQ5 (2xPCM63P-Y), thru Tidal HiFi Plus

It's often in critical listening over same song repeated over (& comparing against) each DAC that I hear and understand the difference, which is actually subtle on my T1.1, HE4Xx, AB SRM-222/SC-1 combo.

In fact, I'm actually quite happy with my then-only 11.38, until I suffered brutal sibilances with SR1A on entire song (Ask of You by Han Dong Geun) that I started searching for R2R as alternative, including older DACs from the begone era, with intention to feed them with modern day jitter-cleanups source I can humbly afford thru U16 DDC.

The sonic quality of R2R11 is as many had raved about that I shall not repeat

strangely, i enjoy SR1A with DEQ5 more than R2R11, even though this old yamaha AD/DA only accept 48k

e.g. in They Can't Take That Away From Me (master), Ella Fitzgerald took a slightly more youthful voice on R2R11 (not sure if it's a good thing) over DEQ5, while DEQ5 brings more realism with Louis Armstrong's signature throaty, gurgling voice.

throw in Trance for fun, bass is fantastic on this pairing (via old Forte 6 AB amp DC bal & high-biased to hot 70mV) that I think no further of complimenting with a sealed sub. Trance on R2R11 is too warmth for my liking, and that narrow its genre.

My point is - there are actually opportunity in older stuff than the usual (more $ modern-day audio) suspects, i.e. if you can overcome the 48k psychological limit.

Close, but R2R11 is not enuff to pull me away from the 63P-Y, because at the end it's all about enjoying what music the DAC can brings.

Regardless, the R2R11 is still a keep.

However, if $$$ allows, I would like to add a preloved pair of Marantz Project D-1 or Zanden 5000 (both Japanese DAC with TDA1541A-S2) , together with modern DS pair of Weiss 501/502. But IMHO, $ on the sound output (headphone/speaker) is a wiser spend with greater noticible difference

 

[sajunky]

I'm a cheapstake in this hobby, with budget DACs in 11.38 ('18) & R2R11mk1 ('19) & DEQ5 (2xPCM63P-Y), thru Tidal HiFi Plus

It's often in critical listening over same song repeated over (& comparing against) each DAC that I hear and understand the difference, which is actually subtle on my T1.1, HE4Xx, AB SRM-222/SC-1 combo.

In fact, I'm actually quite happy with my then-only 11.38, until I suffered brutal sibilances with SR1A on entire song (Ask of You by Han Dong Geun) that I started searching for R2R as alternative, including older DACs from the begone era, with intention to feed them with modern day jitter-cleanups source I can humbly afford thru U16 DDC.

The sonic quality of R2R11 is as many had raved about that I shall not repeat

strangely, i enjoy SR1A with DEQ5 more than R2R11, even though this old yamaha AD/DA only accept 48k

e.g. in They Can't Take That Away From Me (master), Ella Fitzgerald took a slightly more youthful voice on R2R11 (not sure if it's a good thing) over DEQ5, while DEQ5 brings more realism with Louis Armstrong's signature throaty, gurgling voice.

throw in Trance for fun, bass is fantastic on this pairing (via old Forte 6 AB amp DC bal & high-biased to hot 70mV) that I think no further of complimenting with a sealed sub. Trance on R2R11 is too warmth for my liking, and that narrow its genre.

My point is - there are actually opportunity in older stuff than the usual (more $ modern-day audio) suspects, i.e. if you can overcome the 48k psychological limit.

Close, but R2R11 is not enuff to pull me away from the 63P-Y, because at the end it's all about enjoying what music the DAC can brings.

Regardless, the R2R11 is still a keep.

However, if $$$ allows, I would like to add a preloved pair of Marantz Project D-1 or Zanden 5000 (both Japanese DAC with TDA1541A-S2) , together with modern DS pair of Weiss 501/502. But IMHO, $ on the sound output (headphone/speaker) is a wiser spend with greater noticible difference

Interesting about Ella&Luis, as I thought that R2R-11 render a voice very hard, so gurgling should be stronger. I think with R2R-11 you would enjoy upsampling on the PC. DEQ5 is oversampling device if not mistaken, so it would be interesting to see results. Try it with Foobar 2000 and SoX add-on and downloaded CD quality files. With Tidal app it might be not impossible.

 

[Dailydrive]

You are right. R2R-11 render voices well, i.e. if you listen on its own. Value for $ in sound quality; that's why I'll keep it

But if rendered against deq5 side by side with just a switch to toggle betw them, the yamaha sound more natural. Louis's voice is just an example. There are others when it render more realistic emotion to the song than 11, and Im not referring to a case of more/less details or depth.

Kind of difficult to describe in words on naturalness of music but if you have a chance to listen to them side by side, you will understand the something missing in 11 I'm referring to.

 

[Dailydrive]

Interesting about Ella&Luis, as I thought that R2R-11 render a voice very hard, so gurgling should be stronger. I think with R2R-11 you would enjoy upsampling on the PC. DEQ5 is oversampling device if not mistaken, so it would be interesting to see results. Try it with Foobar 2000 and SoX add-on and downloaded CD quality files. With Tidal app it might be not impossible.

Oh.. Forgot to add.

When I received deq5, I had a hard time figuring out its settings.

thinking that I might have brought a lemon (hazard of buying online, esp preloved item, from another country), I reset back to factory original settings in frustration but still no avail

It was another 2 month of sitting idle that I decided to give another try to read its 57-pages operation manual again, and managed to get it play finally, without further tweaking.

In short, I only set it to receive I/O in Digital, In-format as AES/EBU with emphasis "Off"

Nothing is done to its bells & whistles (deq5 equaliser), effectively it is "flat“.

Similar to the R2r11; no change on its jumper settings when brought prelove, neither any knowledge if previous owner made any jumper settings

Thus, it is an "apple to apple" when I made the comparison betw both, side by side

 

[ku1185]

Well it's been 4 months since I've had the r2r-11mk2 and thought I'd post some more thoughts.

I am still very much enjoying it. I am finding that I really appreciate the dynamics in this thing, while maintaining a very smooth and pleasant tonality to everything. I still stick to my initial assessment that details and staging are just a little bit lacking, but will note that playing with inputs (and oversampling) seem to help a little bit in those regards. Unlike some other DACs I've had, I've yet to notice anything that sounds colored, flavored, weird, off, unpleasant, uncanny, etc. It just sounds good to me ears and don't find myself as curious about other DACs.

But as for negatives, I don't like the USB input on this thing, even with the upgraded USB option I purchased. I have instead been using an inexpensive "DDC" (Douk U2 Pro ~$50) and I much prefer the sound out of this setup. Using of the r2r-11mk2's USB input, the imaging feels more "smeared" and "fatter" while stage seems to flatten out. While this does seem to get a little better using cleaner source gear (computer vs. Pi4b+LPS+Volumio), different USB ports (USB2 vs. USB30), and playing trying certain USB cables, I don't find myself preferring it over the DDC. Using the Douk U2 Pro (especially via optical), things seem to open up just a little bit, breathe better, and sounds a little bit better defined. I'm not finding much loss in the dynamics or change in tonality with either case, either.

For what it's worth, I snapped some pictures of the clocks on the USB board and underneath it to help you better determine if it's worth the upgrade:

These are the clocks that came with my upgraded USB r2r-11mk2 but couldn't really figure out what clocks those are. If I could buy it over again, I would forego the USB upgrade (~$70) and just use the Douk U2 Pro (~$60 IIRC) instead for a USB connection from my sources. Of course, you lose ability to upsample up to 384khz as optical is limited to 24/96 and coax is limited to 24/192 (and can't do 176khz for some reason). I personally don't find myself strongly preferring upsampled stuff to regular NOS.

I also have a WiiM Pro on the way and excited to test that.

One other note: on one occassion, while I was playing around with other amps and whatnot, I had changed the volume on the r2r-11mk2, and about a second or two later heard a loud grinding noise as the volume relays were clicking very quickly and volume shot up to 100. This has happened only once, and I suspect it's because the knob was "straddling" the stepped positions on the knob and possibly shorting or something, causing rapid increase in volume. I was fortunate enough to have been playing a quiet song at the time and didn't damage anything. I have since been more mindful of the volume knob and making sure it's resting in a solid position instead of "in between the steps," and I've not experienced any such issues since.

Finally, I do occasionally want for a little more open and spacious sounding amp. While the amp section on the r2r-11mk2 sounds very full, lush, and smooth, it does feel a little cramped. Compared to Soloist 3xp, Magni Piety, and El Amp II, the stage feels smaller and imaging/separation suffers a little bit. Things have a little more "pushed up against you" feeling off of the r2r-11mk2. On the LCD-X 2021 w/ leather pads, it can feel a little "stuffy" out of this amp, but having swapped to vegan leather pads (which sounds more "neutral"--less warmth and less veiled), it does sound more agreeable to my ears. However, I prefer the HD660s (and DT770s) off of this amp than the aforementioned ones.

So despite all of this, I'm still liking the r2r-11mk2 very much. Now I'm curious what their higher end gear sounds like and find myself wishing I'd gotten an R28 or R1+another amp.