CD vs Computer playback on DirectStream


This is my first post, so please bear with me :-) If this has been discussed before (I searched but couldn’t find one), I would appreciate if someone can point me to the thread.

The DS (running Yale) has been great DAC in my system.

Here is what I am trying to figure out - In short, CD playback is far superior and Computer playback. The CD playback creates a lot of
rich harmonics, thicker images and far more depth which are sometimes lost when the same is played through Computer using Async USB (CD rip of lossless flac files). I will come to my setup in a moment but I have tried 192KHz on some albums that were bought from different places, like HDtracks but results are mostly the same. I have ripped some of the CD in wave format but still no luck.

My setup

Source - I play CD through Oppo BDP-105 and its connected to DS through a coax using Rivercable digital cable (which is by far from being a audiophile & expensive cable).

Digital files are played using Jriver on CAPs V3 Zuma on a Dual PC JPlay setup running Windows Server 2012 w/ AO running in Core
mode. Both setup are powered using HDplex linear psu. PPA v2 USB card with JCAT dual-head USB cable between the Audio PC and DS. I have tried other playback s/w, like Bughead and Foobar but results are the same. Both the CAPs runs i7 3.2G (but down clocked to 1.6G). Ram is more than sufficient at 16G. So I don’t think the computer lacks CPU processing power or memory and Jriver was setup according to the instructions on this site.

There is no way for me to verify SACD/DSD playback since Oppo won’t output via coax (or for that matter on any digital output). In the meantime, I will try to play the same digital files through Oppo to see how does their CD counterpart sound relatively.

Anybody face similar situation or could take a stab at what could be the issue ?

Thanks in advance.

You might run the Bit Perfect test to see if the raw bits are getting to the DAC: i.e. that nothing is upsampling or otherwise manipulating the bits. (

another possible problem is ground loops or other issues having a computer tied into your audio system. If you have the choice you might try a TOSLink cable, that will help to narrow things down.


I remember running the bitperfect test earlier when I had set it up couple of months back and it ran fine. I just ran it again now 192k/24 and the DS did say “BitPerfect” reporting the correct sample rate also.

The ground loop is an interesting one - I do have some ground loop hum with my Comcast cable. Both the PC and Oppo is connected to the same Audience power conditioner, however, the Oppo is not connected to the network but the PCs are due to its dual play setup and controlling it via remote desktop from my macbook pro. Both the PCs are connected to switch which in turn is connected to Airport extreme, which in turn is connected to modem.

I am trying to scratch my head and see how can I disconnect the network from the PC source - maybe I will start the album from Jriver and disconnect the switch from the router. Any other possible ideas ?


– Dev

Besides the TOSLink cable you might try just plugging things into different outlets, if the plugs are non-polarized try turning them over.

Tho I don’t have one to recommend you might try a network isolator - something that galvanically isolates one side of your network from the other. I wouldn’t spend too much on it, but it could be good for an experiment.


You are obviously doing a lot of things right in terms of reducing noise from the PC and so forth. Have you looked at the actual USB connection? There has been a lot of talk in this forum and elsewhere recently about the benefits of using things like the AudioQuest Jitterbug or the Uptone Regen. Today’s Paul’s Post has a very good explanation from Ted about why USB suffers from some issues. You might want to try one of these USB gizmos (Full disclosure: I have no connection with anyone who makes or sells them). Based on the description of your system, it seems to be the only thing you haven’t addressed.

Not going to suggest better hardware in this case! Nice.

How are you at BIOS? If BIOS tweaking is not your gig I would leave it alone unless you have a buddy who is experienced. You might peek under the hood and look into shutting down unused USB ports, RS-232 etc. You don’t have fans so no worries there. You might disable hyperthreading and Turbo. Adjust video settings to the lowest resolution and voltages possible (even though you are headless!). I have not experimented with JPlay/AO yet but my experiences with i7 chips is that underclocking them can lead to substantial gains in sound quality although this perhaps runs counter to the conventional philosophy of JPlay/AO users. I’ll bet that you do not have an unlocked i7, however. Undervolting the CPU may give some gains as well but the only way to find out is to try and it is possible with an unlocked CPU. I run mine underclocked, undervolted and in single core mode which sounds great but I am using minimserver with Fidelizer Pro. Try pulling out half of your RAM to reduce noise (forget about what the theories about RAM playback are and give it a try). I wish that I could tell you more but I am just collecting parts for a second computer to experiment with which I will set up for dual mode with JPlay/AO. Good luck. You certainly have a great hardware setup and this is really puzzling.

Oh yeah, Bridge II sounds and works great.wink

Dev said Greetings, There is no way for me to verify SACD/DSD playback since Oppo won’t output via coax (or for that matter on any digital output). In the meantime, I will try to play the same digital files through Oppo to see how does their CD counterpart sound relatively.
Have you tried changing SACD Output to PCM in the Oppo's set-up? This will allow .DSF and .DFF recordings (either on SACD [.DSF] in the first case and for files in either format in the second case) to travel via the coax to the DS DAC. This will kinda even the playing field since RBCDs are PCM and you will be comparing apples to apples. I think.

I experimented with it yesterday night disconnecting the wired lan. I had Oppo and the PC start the same album and I switched inputs on the DS from a remote. Disconnecting the wired lan didn’t work - the more I listen, I am finding the PC sound on the learner side and lacks the musical qualities. The Oppo 105 bass has more weight and fill the room nicely.

Ted, I will try experiment with your ideas.

magister, I have had AQ Jitterbug but I haven’t found it positively contributing to my system. Regen is on order and should be delivered this month.

wglenn, yes I have fiddled around with the Bios and have disabled most of the unnecessary stuff including hyper-threading and virtualization. yes, its a multiplier that reduces the processor voltage and hence make it run at low freq. When I started building this music PC, I started with a single PC and then added Jplay, then added PPA USB card, then a linear power supply, JCAT Usb cable, then AO and then dual PC setup. Each step contributed positively to my system - relaxed presentation, soundstage, etc etc but compared to the Oppo playback, its still not there. I have the Bridge-1 but the PC sound is better I have found.

Joe, if I am not mistakenly, the SACD playback will output only 44kHz ?

Have you tried using only one core on the streaming PC? You can run the lowest voltages in this mode. I know it seems counter intuitive to take a great processor and castrate it but it would be worth a try. I definitely prefer the sound of single core - more natural to my ears.

Welcome Dev…If you like the sound quality of cd playback with the Oppo driving the DS…You would absolutely l-o-v-e the DS with the PWT at the helm. party_gif

wglenn, No I haven’t tried that. Yes, sometimes uni-processor systems are beneficial than multi-core. Its worth the try.

mark-d, Thanks! Now you are taking about WPF (wife permission factor) :-) Nevertheless, I have only heard only good stories on DS + PWT combo. The problem is I no more buy CDs whenever digital files are available and want to get the PC system work desperately.

Welcome, Dev!

A PC can sound superb, but it does take effort. You’ll get there. laugh

Dev, puzzling because I use a single multipurpose i5 desktop PC with JPlay, Fidelizer, and Bug Head and it sounds very good (tho I haven’t adjusted with cpu cores because I found any differences maginal). While I’m not sure it would cause the problems your report, if you have bothersome ground humm an idea is to experiment with a Humm-X unit or two in different power cord positions (I use one with to the computer). I’ve found the Humm-X doesn’t hurt sound quality.

Hey Dev. The stories are true,the PSA combo is killer. I do not do computer audio right now. When the powers that be get it all straighted out, I may look into it then…but for right now I’m very happy with my redbook collection on the dac and transport…dancing-009_gif

I too go to the boss when spending big money…you know what they say…happy wife—happy

I don’t have a DirectStream DAC (yet) but I have compared sound quality from CDs played on a Perfect Wave Transport with the same tracks on a ‘computer’ system. The fundamental difference from your system is that I gave up using USB output from a computer (Mac Mini) to using ethernet output from a NAS running MinimServer. I ended up with a Sonore Rendu as renderer after comparing the sound quality of tracks via those on my shortlist with that from the same tracks on CD. Several of the renderers produced marginally better SQ than the PWT.

As noted by Ted Smith above, a network isolator can produce an improvement in SQ. I use a pair of wire-to-fibre ethernet converters, connected back-to-back by optical fibre, immediately upstream of the Rendu. Result is a subtle but worthwhile improvement in SQ.

Sorry if I sound like the Irishman who, when asked for directions to some place, replied “… well I wouldn’t start from here!”

“tho I haven’t adjusted with cpu cores because I found any differences marginal.” - highstream

Same “hear” if just going to one core. The real changes occur in combination with dropping voltages and underclocking. Single core operation allows lower voltages, in particular, but I must say that the underclock resulted in the biggest change to my ears. YMMV.

Of course one could take the smarter and less nerdy approach of just getting a Sonore Rendu in place of the second computer. I have my eye on the Signature but now have most of what I need to build a second one. Dilemma.


Here is an update - I asked the same question to the Jplay folks and they suggested to experiment with the Jplay streamer mode. So, for the past day or so, I installed Minimserver (as indicated in their manual) on the control pc and used the jplay streamer. Well, the difference in sound is vastly improved. Now its not as good as the Oppo still but getting quiet close. This leads me to believe that their is some fundamental issue with the PC system and I believe its in the power supply. The Minimserver is a very very lightweight application that consumes very least amount of cpu resources and targeted to run in embedded systems. Probably, one big mistake I did was to miscalculate the power budget for both the PC. I use a single HDplex 100w LSU to power both the PC, one PPA USB card and a netgear switch. I think with appropriate power and a good power supply, it might well surpass the Oppo. I got to figure and lay this thing out pretty well.

Thoughts ?



Perhaps it would make sense to scrap the micro ATX/i7 solution and go with a small processor based mobo. An alternative would be to install an unlocked i7 processor in your current PC and “turn down the lights” using underclocking and undervolting and single core. This would be cheaper than a new linear power supply but more work and will also drop the demand on your HDplex. I use a Seasonic ATX fanless power supply (not linear) and have attained the same sound quality as the Digibit Aria using minimserver on a single PC solution. Without performing the underclock I was not able to get there. The Aria, like most commercial servers, uses an embedded low power processor. It seems that to get to this level you need to go low power one way or another.

wglenn, do you currently use Jplay in a single core system ? The reason I ask is Jplay works best when allocated a dedicated core, in fact, it binds to core 1 whenever available upon loading. If I understand Jplay’s philosophy correctly, its trying to solve timing/latency issues with realtime processing. if the software is designed to work best and optimized in a multi-core environment, then putting it in a single core system will limit it’s performance and usability since everything will be serialized (consider several tasks that needs processor cycle at the same time - like scheduler, networking, jplay, etc etc and each of these will be time sliced in a round robin fashion or some other algorithm that Windows incorporate). And this will be true irrespective of how fast a uni-processor is (like i7 ‘K’ vs ‘S’). I have found parallelism to reap huge benefits if the s/w is designed and written that way, not otherwise. On the other hand, the more the number of cores the more the noise. So there has to be a trade off. This was one of the reason why I tried to reduce the operating freq of the processor to reduce some of it. There is not much difference between buying an unlocked i7 vs hdplex lpsu but I would agree if someone was buying an upscale linear psu like Uptone’s JS-2. Having said all these, the proof is in the pudding and only way to find out is to experiment smile


Pity it’s a 105 you have rather than 103 as there is a mod available for the 103 that will let you play the DSD layer from a SACD through coax to the DS. Will also play a BD or DVD in 24bit PCM. It’s a Dutch company called AudioPraise and they manufacture a pc board that replaces the DAC/RCA board at the back of 103 and a piece of cake to swap over. The board is called a Vanity HD and you’ll need to DOP version to pass DSD. It’s available in the US but costs more than the Oppo. I’m in the UK and the Vanity/Oppo cost me just shy of £1200.

Theyve also posted a legal page explaining why the board doesn’t breach any copyright law. I’m in the law and wouldn’t take on a case for Sony given their copyright predates iTunes by about 3 years plus they dumped SACD about a decade ago so no much sympathy there either. Actually their case is undermined by fact that Oppo paid them the SACD and HDMI licenses which were passed onto the consumer plus you bought the SACD.

Just a quick note on coax cables. The Vanity includes RCA sockets that fit in the space where Oppo fitted theirs but they put out a SPDIF signal for up 8 channels. When first hooked up to my DS, I slightly found the sound from my Mac Mini on 24 bit downloads to be better. I was using a Cambridge coax cable that well built and most acceptable at the price. I then heard about a Canadian company, Audiosensibility, whose coax got highly rated. Ordered one including 3 day burn and took over a week to delivered but it knocked spots off the Cambridge. So much for 0’s and 1’s arguments. Still undecided upon whether the Mac is better and too busy enjoying the music to spend ages comparing equipment.