What did a good 10 MHz clock do for your Gustard R26?

I'm auditioning an R26 and it's lovely (musical, high resolution in the microdynamics for example) but a little soft on the highest octave. The imaging is not great. On my speaker system (B&K ST120, Spendor S3/5) the images tend to collapse into left, right, center. I have a guy who does really impressive mods ... beefs up the power supply, adds ERS paper for shielding, bypass caps, etc.... but that's irreversible in case I don't like the result... I'm worried about it getting too bright after the mod. So I thought, why not try a good 10 MHz clock? I don't have the budget for a Mutec, but I could try a less expensive one and have my guy mod it and also create a good BNC cable for it. So I'm wondering what has a good 10 MHz clock done for your R26? Improve the extension on top? Improve the imaging? Has it changed the tonal balance in any way? I'd like more extended but not brighter.


Whats wrong with Gustard C18. Or C16.

Now, i found denafrips to be MUCH better gear.

When I owned the R26 I found the LHY OCK-2 external clock with a LMR400 cable made a significant difference in how it sounded.  Amazingly, cables do matter and the do require quite a bit of burn in.  I though it added tonal density and presence.  I don't believe I noticed any change in the soundstage.  I felt the improvement was easily noticeable and since you can switch in and out of using the external clock with the remote it is easy to verify.  The R26 should have a very nice, wide, well placed and defined soundstage but it isn't as deep as some more expensive DACs.

@vinylvalet +2

IME ie in my system the R26 is an imaging champ and not rolled off at all on top. Funny how system-specific all gear is, makes you wonder about the true value of reviews or even forum-combing for consensus on a particular piece of gear.

Kinda a crap shoot really the whole system building thing.

@kairosman I'm starting to suspect I have a bad unit. This is my second attempt to purchase the R26. The first one was very dark to the point of sounding broken. This one is better but still soft in the top octave, and the problem with imaging is very curious (I get fantastic imaging on other DACs). I have about 100 hours of burn-in on the R26 so I'm going to give it another 100 hours.

@magon what settings are you using for filter and NOS mode? What cables are you using?

Most importantly detail what your definition of imaging is, I find significant differences between people in how they define that parameter...

@kairosman I'm using custom cabling (interconnects, power cords, USB cable) by the same guy who modified my x20pro... it's very good stuff. His friends in the N.J. Audio Society say it compares favorably to multiple-$1000 commercial stuff, but I've never heard anything other than Igor's cable except for low-end Cardas and such. The "slow" filter sounded best for detail and microdynamics. I didn't like NOS much. 

When I refer to imaging I'm actually talking not about my headphones but about my humble speakers... Spendor S3/5. They have great imaging with my modified Gustard x20pro, in terms of the spooky realistic sense that you can face the direct source of sound and pinpoint its location in space. With the R26 the images tend to exist in either left, center, or right, and not be stable. The sizzle on a violin might seem to come from a different place than the body of it. 

The headspace of the R26, with headphones, is decent. I like a sense of open sound when I'm using headphones, i.e. that the boundaries of my head aren't precisely limited, and I get that with the R26. 

What my R26 does really well is soft music, like the fade to silence (or fade up from silence) of a reed instrument. But in general it seems too soft in the top octave.. it requires careful attention to pick up on details. It doesn't grab me like the x20pro. 

Right now, it's playing pink noise through my relatively new LCD-X, so we'll see how they both sound in a few days when it reaches 200 hours.


It's complicated. I don't have the R26, but I do have the x26 PRO. I first added the C18 master clock to clock both the X26 and LHY-SW10 ethernet switch. It didn't make much of a difference for my Innuos ZENith mk3 streamer connected to the X26 PRO via Network Acoustic Eno III USB cable. However, I then added a DDC U18 to feed the USB cable into it and exiting via a I2s Purist HDMI cable to the X26 PRO.  And the U18 is also clocked by the C18. And WOW!!!

The sound has taken a big leap forward in every way. It's complicated because doing all these upgrades is what finally brought it all together. Exactly what did what is hard to say except that the DDC to send the USB into I2s via Purist cable was a major factor. Just adding a master clock without going any further would not give you that wow factor.




In the end, like many, I do now agree that a master clock is valuable to clock multiple pieces together but is not very effective reclocking a single unit. It only makes sense.

The overall tone of this thread reads like a warning to me. The OP is trying out a second unit because the first sounded dark and broken. Now the second unit the  imaging collapses and the highest octave is soft. I also read several other posters have added modifications to their R26s from clocks to cables in order to achieve the desired performance level. Clocks can add $750 up to $5500 to a $1700 component. I wish you luck in this pursuit. I also believe you and others will be successful due to your knowledge and dedication and obvious discerning audio talent. This one is not for me, my budget is more like spend $1700 but don't take chances @jolywins 

After having issues with the second unit if it was me I’d absolutely cut bait and move on as there are so many other excellent DACs out there.  The Denafrips Pontus jumps to mind, and adding their Iris DDC at some point will give you the ability to take advantage of its i2S connection and get a significant performance boost for not much more $$$ especially if you buy used (that’s what I did).  Just my $0.02 FWIW.

Found the best solution for my R26 was Gustard C-18 clock output to U18 DDC (set to Ext. Reference). Use good quality coax cable here. Experiment with square wave vs sine wave clock output. Sine wave output is less sensitive to cable impedance (U18 clock input is 50 ohm - make sure to use equivalent impedance cable if using square wave output). 

U18 is fed USB from server (in my case Antipodes K30). R26 gets the I2S output from U18 (make sure R26 is set to Int. Ref for clock). I2S cable supplies data and 10M externally referenced clock signal from U18. Once again -  a high quality !2S cable is important (Tubulus for me).

Sounds great to me. In this setup I believe the overall quality of the server is of greater importance and contributes more to the sound quality than the dac. I'm feeding the U18 with upsampled PCM (via PGGB - files served from internal SSD on the K30) at 705/768 kHz/32 bit. The R26 is set to NOS mode.



For the sake of argument, since I basically have a similar system as dspringham in above post, but unlike him I keep the dac on ext clock which provides a wider more expanded sound than using the int clock. I am of the school that thinks the entire chain gains from being on the same master clock, even I2s. At least it is true to my ears in this system.

For the sake of argument, since I basically have a similar system as dspringham in above post, but unlike him I keep the dac on ext clock which provides a wider more expanded sound than using the int clock. I am of the school that thinks the entire chain gains from being on the same master clock, even I2s. At least it is true to my ears in this system.


When you run the clock cable to the DDC on Ext Ref and then I2S from DDC to DAC, the 10Mhz clock signal is supplied to the DAC via the I2S signal. There is no need to run another clock feed as external reference for the DAC. In this case, the DAC clock should be set to Internal. When used in this fashion with I2S It is redundant to run separate 10 Mhz clocks to both the DDC and the DAC. Saves the cost of an additional clock cable.





@audphile1 You're talking about my R26 right? Mine doesn't seem to match the descriptions of others' R26s. Like the imaging. I suspect mine is broken.

I got a Gustard 10 MHz clock, the $750 or so model, from Amazon, could return. After an hour of warmup of the clock (the R26 DAC was already warmed up), I hear an improvement in extension and tonal balance, more midrange where there seems to be an upper midrange recession in the stock R26. But it's a small difference. Call it one step of difference. I would want about 5 steps of difference to be worth $1000 (The Gustard clock plus Gustard clock cable plus tax). I don't think I'm keeping either the clock or the R26. Not sure what I'll do. Maybe just go back to previous DAC (a modified iFi iDSD Nano, surprisingly good after mods). And wait. Maybe try the Denafrips.

Yep I’m talking about R26. If you have a second unit that doesn’t sound right then you should be done. 

there’s a lot of hype going on around the LAiV Harmony DAC. May be try that? Seems to be receiving lots of praise from the reviewers. 

@magon yeah maybe cut bait and run if you're not happy, return the clock and sell the R26, the aftermarket price for them is pretty decent.

I've owned a Denafrips Terminator II (sold it to fund a Lampizator Baltic V4) and would recommend the brand, good sonically, good rep, excellent after sales service and warranty support, seems the new Pontus is a sweet spot in the lineup but you will also definitely need one of their DDCs to fully exploit its capabilities.

Another good DAC I own is the Weiss 204, you won't need a DDC or clock with it, lots of reviews and forum posts about it.

@magon so by now you’ve tried 3 dacs. Gustard R26, your modified Gustard and the PS Audio DSD MkI. Just to summarize…R26 is dark and dull, the PS Audio is too bright, snd the modified Gustard is just right?

This begs the question - have you tuned your headphone and speaker system (s) to the sound of modified Gustard so much that the other two DACs don’t sound right? Both R26 units sounded broken. And I’m most surprised about your assessment of PS Audio DSD. That DAC is anything but bright. So my suggestion based on this DAC shootout you have conducted, is to take a close look at your system, room and the associated equipment as I suspect you have created a synergy for that particular modified DAC and now nothing else can integrate. Is it possible?

@audphile1 I suppose it's possible, but if my system has a characteristic tonal balance, why would it be too dark on one DAC and too bright on another? 

But curiously enough, a lot of my system is modified or custom by the same guy who modified the Gustard x20pro. He did my power conditioning (which is based on parallel capacitance concentrated on my system circuit but also distributed throughout the house), my power cords, interconnects, headphone, and USB cable, and modified my headphone amp. Also speaker cable. My Aurender N100 is stock and I've found that greatly improves any DAC it's feeding compared to my previous mini PC. Obviously I really like the sonic character of Igor's work - very extended on top without being bright, deep musical bass, great dynamics (micro and macro), musical details, etc. 

My speakers are stock - Spendor S3/5, and so is my B&K ST120 amp (from the 70's - great amp - mine is excellent condition and low use). 

As far as what parts of my system affect tonal balance, the headphones are the obvious culprit. I have obtained loans or second hand purchases of several headphones and more will be here soon. I really want to give this a chance before I return the R26. 

What I haven't mentioned is that the modified X20Pro stimulates some kind of resonance in my left ear that has something to do with my tinnitus. Certain pitches sound like they've hit a high-Q resonance. Very odd. I'm going to see an ENT about it. For some reason the modified Gustard stimulates the resonance like crazy, which became more obvious when feeding it from the Aurender, while the modified iFi iDSD doesn't stimulate the resonance at all. And the R26, only a little bit. I want to keep the Aurender as it's so promising, and Igor agreed to trade the X20Pro for future work. So my goal is to match the Aurender with some other DAC that doesn't stimulate the resonance. Oh, the PS Audio doesn't stimulate the resonance.

Thanks for your feedback. I'm sorry I made it so complicated. But I have patience. It's been fun to try a lot of stuff - very educational for my ear. 

@magon interesting. So…couple of things…

I’m also using Aurender, but N200, to feed my PS Audio DSD MkI. I have never experienced any brightness with it. The bass is prodigious. The vocals are velvety smooth. So there’s something there in the associated equipment in your system that doesn’t match. Could be impedance mismatch between B&K amp and PS Audio DSD (not sure if you use preamp). 
As to modified gear - I’ve had bad experience with a modified amp. I loved it in its stock form but it was horrible after mods. It caused tremendous fatigue and I couldn’t listen to my system. That was it for me as far as mods are concerned. Keep in mind that a manufacturer will voice their product to be as neutral as possible. Changing parts, even for better quality ones, doesn’t always result in better sound. In addition, selling a modified component becomes more difficult as the sound signature was altered and the potential buyers understand it. It becomes unpredictable and no one can anticipate what it will sound like. Same applies to cables - the DIYers of the world don’t have the means and the equipment to come up with a cable that would work with wide range of components - they usually tune it to their personal preference using the components available to them at the time. 
I wish you luck in your quest for a better dac and have that tinnitus checked out for sure. 

Everyone likes a good 10 mHz clock.

Contacting tech support to get them adjusted for daylight savings time every 6 months is rather inconvenient.

"When you run the clock cable to the DDC on Ext Ref and then I2S from DDC to DAC, the 10Mhz clock signal is supplied to the DAC via the I2S signal. There is no need to run another clock feed as external reference for the DAC. In this case, the DAC clock should be set to Internal. When used in this fashion with I2S It is redundant to run separate 10 Mhz clocks to both the DDC and the DAC. Saves the cost of an additional clock cable."

I'm not super knowledgeable about some of these connections and need a little help - I'm using a Gustard x26 Pro.  I began by using the USB input.  My first upgrade was to use a cheap Douk Audio DDC with a decent LPS so I could use the I2S input in the DAC.  This was an improvement for me.  My next upgrade was an Afterdark external clock.  This was another improvement.  Now I'm reading the above post and I'm looking at a Gustard U18 DDC.  Looking at the back panel of the U18 there is a BNC connector marked as an input "1OMCLK".  There is also a BNC output marked "WCK".  If I understand the post, I can use my Afterdark clock with the DDC and then simply use an HDMI connection to the DAC and I will get the benefit of using the external clock with the DAC as well.  Is this correct?  Thanks for any help.



While I do recognize that my system might have some kind of "signature" as a whole that is obscuring these components, I've had a very good experience with Igor's mods. I started with just his power conditioning (but all stock components at the time). It made my system more extended on top and more musical by quite a lot. In particular it made things more extended by not brighter. Everything he's done since has built on that. I've carried some of his modified components to other people's systems and they bring similar qualities. Like, a long time ago when I still used CD I brought his modified PS Audio Lambda II to a friend's system and it improved the extension without making the system brighter. I've been in contact with folks in the New Jersey Audiophile Society who use his cables rather than the $5000 cables they could easily afford. He mainly takes moderate priced equipment and brings out the potential - so for instance my headphone amp is a Chinese 12AU7/FET zero-feedback design that comes with a SMPS ($100 new!). He replaced all the parts, added shielding through ERS fabric, added damping, and designed a LPS. Many people in the headphone community praise the concept of 12AY7/FET designs, so it's not surprising how good it is.

With the PS Audio DAC, I'm feeding that by a stock Aurender through Igor's USB cable. Tell you what, I'll replace that with a stock USB cable and test it. Then everything will be stock components except the headphone amp. I'll try it with several headphones through their stock cables. Let's see if it changes the tonal balance or component signature.


@magon actually not a bad idea! I always go back to stock cables to set a baseline for a component’s sound when evaluating it. Aurender includes a very nice usb cable if you still have it, worth a try. Or just use any basic usb and power cord. 
Awaiting your updates. 

Looking at the back panel of the U18 there is a BNC connector marked as an input "1OMCLK".  There is also a BNC output marked "WCK".  If I understand the post, I can use my Afterdark clock with the DDC and then simply use an HDMI connection to the DAC and I will get the benefit of using the external clock with the DAC as well.  Is this correct? 

Yes, correct - Just make sure the DDC is set to External Clock and the DAC clock reference is set to Internal when using the I2S input.




@audphile1 Whoa... went to an iFi USB cable (maybe $150 when I bought it 7 years ago) and the brightness in the PS Audio is gone! The strangeness in the bass is gone. It's still a bit bass-light compared to the two Gustards I've had in my possession, but it's much closer to something balanced. It's also less exciting, less microdynamic, less resolution.... but it suggests that I could look for a USB cable with all that resolution, and also the correct tonal balance to boot. Or perhaps drive a D-D convertor through my original USB cable and then drive the PS Audio via coax or something else. 


Interesting. Take few days to get used to the sound and run it 24/7 to let the cable settle. The PS Audio DAC won’t scream look at me I’m here and attract attention to itself. But it plays music in a very satisfying way. Nothing stands out. 
It takes a bit of time to get used to it if you’re coming from a more analytical dac. 

I got a hold of a Cardas Clear USB (the top of the line Cardas USB, $450 new) and it works beautifully with the PS Audio. Good resolution, beautiful timbre, and all the bass and brightness problems are solved.

In the previous comment I mentioned an iFi USB cable. That was okay, but after listening for a few hours, it was clear it lacked beauty of timbre and it was grainy on piano.

@audphile1 I did put Igor's best PC on it. The members of the N.J. Audiophile Society tell me it can compete with $5K power cords. Of course this might be introducing Igor's signature again, but I don't think so, because the weirdness all went away with the USB cable switch. 

I listened for a while through two different headphones -- LCD-2 (pre-fazor) and 2021 LCD-X. The LCD-2 is dark, and not a good match for the PS Audio.. it just sounds rolled-off with this combination. But the LCD-2 has a very beautiful midrange, and that came through clearly. I also listened to the PS Audio on speakers and noticed the extraordinarily beautiful midrange and deep musical expression - and like you say, it does require attentiveness on the listener's part, because the PS Audio isn't exactly "grab ya by the collar."

I then listened through the LCD-X, which has a much better overall tonal balance, something generally true of Audeze's fazor headphones. The sound was more interesting and attention-grabbing with the highs no longer rolled-off. But unfortunately there wasn't as much musical expression. The fazor LCD-X has a less beautiful midrange than my LCD-2. I couldn't go with the LCD-X for my long-term listening.

I then switched to my Gustard R26 with the C26 clock. The sound was much more lively and a better match for the LCD-2. In testing the PS Audio and the Gustard, I listened to Maria Schneider's "Walking by Flashlight" for big band, which builds to a climax on a beautiful, very rich/complex chord near the end. The PS Audio emphasized the beauty of this chord. The Gustard emphasized more the climatic nature of it, giving a better sense of shape and finality to the piece.

Because the Gustard is a better match for the LCD-2 (and at this time I don't want to start a whole new search for the perfect headphone), and because I find it more important to make climaxes exciting, I think I'm going to go with the Gustard, which by the way is much improved with the Cardas USB and the C16 clock. I started this thread complaining about the Gustard R26, but it seems pretty resolved. It still needs more oomph, especially in quiet music. My goal is to make quiet music, and sudden pianissimo, as captivating as loud music. (Something true of live instruments.) Maybe a better clock or clock cable.


Cool. You have to go with whatever suits your preference and perception of best sound. It took me a while to begin appreciating the PS Audio DAC after the somewhat more forward and resolving but cooler sounding Bricasti M3 and now I just love the DSD DAC sound. It’s all about synergy and personal taste.

I love the PS Audio DS Dac's beauty and musical expressiveness. If I could find the right headphone with it, something more balanced than my LCD-2 yet with an equally beautiful midrange, I would go with the DSD no question. I've just run out of time in all this searching.

I don't understand why people buy external clocks. The dac itself should already come with an excellent clock. Not sure I like the idea about adding an additional box to address a deficient clock within a dac.  Plenty of higher end dacs have excellent clocks.  Maybe you're stuck with a deficient dac that should be replaced.


I don't like separate dacs and I have a couple but I purchased a lumin x1 which is a streamer/dac and that's working out really well.  I don't have to fiddle with extra connections and tormenting myself with a feeling I need to consider a new dac. Also the internal wiring if done well to connect a really good dac capability is far superior than dealing with additional interconnects, etc 

I'm not a fan of integrateds, but in these couple of areas above it would seem to me justifiable

I don’t understand why people buy external clocks.

Well we’ll just add that to the already huge and growing pile. I sense yet another inane thread coming our way. 🤪🙄

The Gustard C16 external clock has an OCXO with its own power supply. The R26 has a crystal but not at the level of an OCXO, and it's rare to find a DAC with a separate power supply for the clock. That's part of the benefit of an external clock.

I may have changed my mind. You should probably ignore me because I keep changing it, but I listened to another DAC this weekend (the Denafrips Terminator 1), and tried another USB cable between my Aurender and each of my DAC options. I also considered that whatever I do I'll probably have this technician friend (Igor in New Jersey) modify the DAC, and in the case of the PS Audio he can do the well-known transformer and VOCM mods, which will probably increase the resale value as it's well regarded. I decided that the PS Audio has many strengths (such as faithful/beautiful timbre and musicality) and its only weakness is a bit lacking in oomph and resolution compared to the Denafrips or my previous DAC, the modified X20 pro. Well, Igor can fix that. The R26 and Denafrips had more weaknesses with no guarantee they can be fixed. So I think the winner at this point is the PS Audio! And off to the shop to get the transformer and VOCM mod, plus a power supply component upgrade. Anyway that's the plan. I keep changing it, but I'll know for sure at least by the time the R26 has to be returned to Amazon.