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Conversion of a Chord DAVE to DC power using two Uptone Audio JS-2s

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@MarkusBarkusYes, dreamy indeed! I'm like 'the cat that got the cream' now when I listen.


I'm now turning my thoughts to the Blu Mk II, and I'm curious to know if you use one (or a Hugo MScalar) with your DAVE, and if so whether you've (or anyone else reading this) tried similarly improving the power supply and with what result?


I had a quick peek inside the Blu Mk II and I think its the same SMPS as in DAVE, but there looks to be more PCB in close proximity around it.

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That's so interesting @ecwl, sounds like good thinking to go into the device optically. I also spoke to Rob, a couple of years ago now, and know his opinion is that good quality 24 bit recordings are more impactful on quality than high sample rate. I have to admit I used to seek out High Res files, but since the advent of streaming and MScaler I'm really happy with 44.1k. Although I do beg to differ with him about those SMPS he uses, given my recent experiences...


I am also considering that same swap of Blu Mk II for MScaler that you did, I have literally used the CD part once. It was the only game in town when I got it, but the fact the MScaler is already DC capable is pretty attractive to me...


Where in Canda are you? My wife is Canadian, from Nova Scotia. We go back there two or three times a year (in normal times) but I haven't found too many fellow audiophiles. Sadly I tend to not have much to contribute to conversations about lobster fishing, hunting and trucks... ;)


Your room convolution experiences sound fascinating. For me Dirac, I thought at the time, was ironically too successful - by taking the room totally out of the equation I thought the sense of soundstage and 'musicians in the room' was lacking in the final analysis. I started using it as an 'insurance policy' just before I got my 800 D3's as I have a smallish listening room and wanted to be sure I would be able to control the energy they are capable of putting into the room, but have been able to sort things so its not needed, and is better now. My long term endgame goal does involve filtering though, I want to use Roon DSP to implement a digital crossover(s) with high end DAC & good power amp per driver. For which the DACs need to be able to synchronise clocks.


Anyway, sounds like I have some catching up to do on Head-Fi - thanks, and all the best!

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12 hours ago, ecwl said:

I think the consensus is that you’re better off asking @mitchco to help you create a convolution filter in Roon.

Thanks (again) @ecwl - I appreciate the pointer re: @mitchco, I will try and look out the thread and investigate.


If you ever feel able to investigate swapping out the SMPS in the DAVE, I can only recommend it based on my experience - it, too, is shockingly better :)


All the best.


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3 hours ago, asdf1000 said:


Btw: I don't write all this just to argue.



Thanks for your posts - I'm sure you are right re: measurements etc.


I don't really have a grasp of the theory(s) but based on my experience I'm convinced that taking the SMPS out of the DAVE is one of the best upgrades I've ever done, whatever the reason for the improvement.


It's the hobby that keeps on giving. Barely gives one any spare time to listen to music... ;)

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15 hours ago, skatbelt said:


I agree with you. With the development of DAVE, Rob Watts mission was to design a state of the art DAC within the technological possibilities (at the moment). I therefore see the choice of a SMPS as part of the overall the design decisions. If a LPS would have fitted better within this philosophy and contributed positively to the objectives, then he would undoubtedly have chosen that route. 


There are very good SMPS's and very bad SMPS's just as there are good and bad LPS's. The problem in high end audio is that SMPS almost seems to be a curse word because of the image that is created by the large group of very cheap and noisy ones.


I also have reservations about the objectivity of the OP's assessment. Unless he directly A/B-ed his modified DAVE with a 'standard DAVE' ceteris paribus I cannot take 'shockingly better' very serious.


On the other hand, I have experienced that DAVE is sensitive to the quality of the power provided. For example, a dedicated power line, an isolation transformer with balanced power and a better power cable all brought audible improvements in my system.

Thanks for your comments @skatbelt


One would hope Rob / Chord took the approach you describe, I'm simply reporting that I heard very meaningful improvements after the switch (as have others).


You raise a fair point about objectivity, and of course as I don't have two DAVE's I can't easily do repeated A/Bs. The conversion took maybe 20 minutes in all, so there is that gap too. However, set against those potential issues are the facts that I was using tracks that are VERY well known to me, same volume levels, the conversion was done after about an hour or so of acclimatisation of listening with my friend (so his and my wife's opinions too, not just mine), and I was actually not expecting that much to change (if anything). That's really the reason I posted about it; it was such a dramatic change when there are many reasons to expect it to be subtle, at best. I remain delighted with it.


On another topic, I'm really interested in your experiences with your isolation transformer, having had a dedicated mains spur put in over the summer.  I'll try and read up more about it myself, but presumably the reason you do this is to further reduce mains noise? Do you have any before & after measurements? Also a question about the transformer size, am I direct in thinking that do you need to match up the transformer spec with the needs of the electronics 'behind' it, particularly the power amp?


Thanks in advance for any information.

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3 hours ago, ecwl said:

I’d probably look to see if there are any bass peaks to tune out using parametric EQ in Roon.

Thanks for the thought @ecwl; thats actually exactly what I did after I got my room as good as I could the 'old fashioned' way, and had only minor uplifts corresponding to the room L, W, & H.


I found that I couldn't really tell any difference with the parametric EQ in or out, so decided to leave it off.


I'm pretty certain now that I'm going to swap Blu Mk II for Hugo MScaler and use a JS-2 for power, I think there were RFI improvements to it compared to Blu Mk II.

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2 hours ago, skatbelt said:


I won't start a psychological discussion... :)


There is a whole thread in this sponsored forum about isolation transformers, infused by - who else? - John Swenson:




When implemented properly it will reduce high frequency common mode noise on the AC line. All details can be found in the thread. It is quite a read so in short you'll need an isolation transformer that has enough headroom to power the needed wattage behind it and one that has extreme low so called interwinding capacitance. You need to power all components behind the transformer from one power strip and make this part of the system a closed group in electrical terms. So, no copper connections with powered components that aren't part of the group to prevent from leakage currents.


I have mine wired for balanced power. It is a moderate 1KVA model but this plenty enough to power a dCS Network Bridge, DAVE and a Lyngdorf TDAI-3400. The uptream network components are isolated via an etherREGEN and a separately powered subwoofer is isolated via a Jensen transformer.


I perceived implementing this as a full component upgrade with added tranquility, ease and realness and at the same time more details in sound reproduction. The difference between balanced/symmetrical vs. asymmetrical was quite shocking to stay in your terms... :)




Thanks so much for taking the time to explain all that @skatbelt, I really appreciate it.


I'll definitely dig into that thread in the coming weeks for the details.


I heard changes like the ones you describe when I switched to a separate power line, but I'd imagine there is still noise on there. I'm still working out how to measure the noise to see what the extent of any further gains might be...

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3 minutes ago, ecwl said:

Sounds like you just don’t have any major problematic bass peaks. Usually if you have peaks more than 5dB, an exact parametric EQ to tune it out would make a pretty obvious difference. Correcting troughs usually don’t work.


And yes, I suspect in your system, JS-2 + HMS probably would sound better than Blu Mk II. Even without the JS-2, the USB input of the Blu Mk II is not galvanically isolated whereas the HMS one is. So that alone would probably gives a bit of improvement. Although maybe not because you already have lots of ferrites on your dual BNC cables. I don’t use ferrites. I think Rob Watts thinks adding ferrites between HMS and DAVE actually makes things worse? Whereas ferrites between Blu2 and DAVE are better.


Ah thanks for the info on HMS - sounds like he learned some lessons from Blu Mk II then! I did not know that about the USB.


At least ferrites on vs. off the BNC cables is a pretty easy A/B to do!

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Thanks @ecwl and @MarkusBarkus, very useful.


As I understand it the USB interface on the Blu Mk II itself was a last minute addition based on dealer feedback on the prototypes, so perhaps there wasn't time for a thorough job.


I believe the 'RFI' on those BNCs is derived from the clock frequency of the FPGA in the Blu and HMS. It sounds like I should be prepared to keep the ferrite cores on my BNCs regardless (but I will experiment of course!). I wonder if there is any form of optical replacement of BNC cables that someone out there in internet land has tried? That would probably end up being a minefield of noise from the transceivers, power supply angst etc... in itself, but probably worth a Google at some point, though.


edit: hah: https://audiobacon.net/2020/02/22/audiowise-opto-dx-the-rf-noise-killer/

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Oh my goodness @ecwl @skatbelt @asdf1000


This epic Head-Fi review / article / journey is incredibly comprehensive and touches on pretty much all the topics we have all talked about / around in this thread.


Recommended reading, when you've got a fair amount of spare time, and its worth getting through to the end. Also worth reading his linked piece about his DIY 'Ferrite Cable of Shame' as background.

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2 minutes ago, skatbelt said:

Hmmm, there goes my assumption of purposely built or at least custom built to spec for Chord.


This Head-fi post is Rob Watts on the medical SMPS, whats important in a PSU for his DACs and the further conditioning measures he uses in the DAVE, post PSU.


" Would using a better SMPS give better SQ? Maybe, but the evidence suggests no. "


I read that piece before deciding to give the JS-2s a go, and you know my conclusion: 😳. ;)

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16 minutes ago, Nenon said:


I have noticed that the older DAVE DACs use the above off-the-shelf product. The newer manufactured units I have seen, 2020 in particular, had this one - EOS Power LFWLT40-3002. It's a $15 power supply on a $10K+ DAC. No wonder we all like this upgrade :). 


They can talk as much as they want about voicing, but...




In other words, the voicing around the $15 SMPS was not really something I liked in my system. 




Rob's Head-fi post indicates that not a great deal of thought went into the SMPS (no A/B testing, @skatbelt😱 ) despite all the downstream work he describes.


To paraphrase @kennyb123, best to combine the world-class elements that each of these leading individuals bring to the table and 'tune out' other elements based on our own experiences and preferences.


Though it would have been nice to have an external DC input, as with HMS, to allow for experimentation without voiding the warranty... 🧐

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  • 1 month later...
On 1/15/2021 at 1:45 AM, ray-dude said:


Quick update: after a couple months of running the DC4 7/24, it was fully burned in so I was able to get to get my deep dive done over the holidays. (note to self: never sign up for a review of a component with giant Mundorf caps unless you have time/patience for a couple months of burn in)

TL;DR - It's awesome with DAVE!

Look for the multi-part (sorry, I couldn't help myself ;) review to be posted pretty soon.

 @ray-dude Fantastic, thanks for letting me / us know - I'm looking forward to setting aside the time to read it ;)


Don't forget to let everyone know that other LPS' are available... 


Quick update from my end; I have just got round to earthing all the unused inputs on my DAVE (couple of BNC's, XLR and USB) and Blu Mk II and was pleased with the improvement / effort ratio - further reduces the RF noise, a 'calmer' listen. Should have done it long ago. You guys have probably done it already, but I mention it 'just in case'.


Over the next few days / week I'll be DC converting the Blu Mk II, will post her about how I get on. Wish me luck!

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25 minutes ago, asdf1000 said:

I'm not question the improvement you hear but this is generally not recommended practise (earthing all inputs).


I don't think this would be recommended by John S or Rob Watts.

Interesting thanks - do you know what the issue might be? It seemed like a logical thing to do to me.

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4 minutes ago, asdf1000 said:


All good. I don't know if that's any better though 😀


The main thing is it didn't get worse for you, which is the biggest danger with improper system grounding - when you start to hear audible buzz/hum.


And I guess it is possible that (by luck) you actually have objectively improved things too. 


It's such a complicated thing that the only way to get good advice on system grounding is to sketch up a full system diagram LOL. Showing how everything is connection.


That's a lot of work but it's really the only way an expert here (not me) could give good advice.


Other than that, reading the Rane article is a great place to start.

@asdf1000 I'm coming at it from trying to tame the RF sensitivity of the DAVE and Blu Mk II - I definitely feel like I'm on the front foot of the battle at the moment. I'll take my lucky shot!

I feel it did help me, but I will be sure to be mindful in future.


Thanks again for taking the time to reply and your advice, its much appreciated.

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