@vortecjr All inputs on the PWD II go through a digital lens to reduce jitter (the digital lens being a re-clocking circuit I believe). I2S inputs on the PWD II go through a second digital lens when nativeX is selected. Many have found this improves the SQ, myself included. Paul might chime in here if I have this wrong…
One of the issues I have with USB is the cable itself and the way it is transmitted. USB is a two-way communication that really depends on a good connection and cable to work at all - hence the restriction of cable length - where I2S over HDMI has none of those restrictions and is a one-way communication.
Having said that, the second Digital Lens you’re referring to is NativeX - and while not a true Digital Lens (there is no RAM involved) it does cleanup jitter nicely and USB or HDMI will pass through this for good benefit.
The Bridge has its own reclocking device onboard and it outputs I2S as well (it’s really just another I2S input) and I believe what Jesus is referring to is somewhat the same thing only physically separated from the PWD MKII - which certainly can have advantages and disadvantages depending (in this case) on the cable.
Paul, he has a server with a built in USB to HDMI/i2s converter all powered by a standard SMPS. The same server also has USB output. He seems to prefer the i2s output on the server. I can’t argue his preference, but I think it’s important to explain the best use of these formats. I don’t agree with the results based on the technical merits of the formats as used and extensive testing I have conducted for our own projects. I’m considering the following: 1. The USB to i2s converter in your DAC is powered from a linear supply verses the SMPS in the server. 2. The server has the additional conversion from i2s to LVDS i2s. 3. He is having issues with the reclocker in the DAC locking on to one or two sample rates. This tells me that the incoming jitter at those rates from the HDMI/i2s output is outside the bandwidth of the reclocker. The fact that he is not having issues with the same server via USB at the same rates means that the jitter is lower via USB. Having said that, there are ways to improve the server with a better power supply and with an SOtM USB card. The power supply will improve the USB and HDMI/i2s output, but no guarantee it will solve the locking issue. The SOtM USB card will only improve the USB output. Again I’m not trying to argue his preference…
Jesus R
I can’t argue with your logic Jesus. Your explanation of the implementation of the I2s over HDMI in the W4S server should mean it is no better than USB, if anything, it should be worse. I had wrongly thought i2s was dealt with differently to USB in the PWD II, but Paul’s advice is that in nativeX mode, they are processed similarly.
USB cable seems to make a difference in SQ, even when the implementation of USB interface is asynchronous, and perhaps this is relevant to the SQ difference I have found.
I have always tried audio equipment with a view to listen first, explain later. When I have USB working again I’ll work on testing different USB cables to see if this affects SQ.
A bit later this year I’m going to try a Paul style “shootout” between the bridge, the W4S server, and a bryston BP-2 (on loan). Final result aside, it will be great fun! And that’s what it’s about for me.
I can't argue with your logic Jesus. Your explanation of the implementation of the I2s over HDMI in the W4S server should mean it is no better than USB, if anything, it should be worse. I had wrongly thought i2s was dealt with differently to USB in the PWD II, but Paul's advice is that in nativeX mode, they are processed similarly.
USB cable seems to make a difference in SQ, even when the implementation of USB interface is asynchronous, and perhaps this is relevant to the SQ difference I have found.
I have always tried audio equipment with a view to listen first, explain later. When I have USB working again I'll work on testing different USB cables to see if this affects SQ.
A bit later this year I'm going to try a Paul style "shootout" between the bridge, the W4S server, and a bryston BP-2 (on loan). Final result aside, it will be great fun! And that's what it's about for me.
Looking forward to this, stereophilus.
I do not believe that an internal conversion to USB is a good thing, as Gordon mentioned.
@stereophilus, your right…this should all be fun! The things to try next are a good power supply and good cable. You can’t use the SOtM card on that server, but the reason for it is that it provides needed isolation on it’s USB outputs…
Jesus R
"A bit later this year I'm going to try a Paul style "shootout" between the bridge, the W4S server, and a bryston BP-2 (on loan). Final result aside, it will be great fun! And that's what it's about for me."
I WILL BUY THE BEVERAGES -- send the dates!
Post the results as soon as the smoke clears from the shootout!
@vortecjr I’m not much of a “hardware tinkerer”, so internal mods are a stretch for me, Jesus. Cables I can do!
Just as I mention my 3-way shootout, Jesus tells us the Sonore rendu now does gapless over i2s in nativeX… I may have to do a 4-way shootout! This has the makings of a classic spaghetti western.
<)
stereophilus said: Jesus tells us the Sonore rendu now does gapless over i2s in nativeX... I may have to do a 4-way shootout! This has the makings of a classic spaghetti western.
This is indeed good news. I too am anxious to hear of the results.
Got the USB working again… An annoying little trick is needed to get both HDMI and USB output at the same time from ms2/PWD II combo. First reboot the server with the i2s input selected on the PWD II. Then once the ms2 is running, power cycle the PWD II to get USB input to work. This is needed only to get both outputs functional at the same time, for comparisons.
Second point I need to clarify. I did mention 88.2 kHz sample rates don’t work over i2s into the PWD. This is wrong, the only sample rate not working over i2s is 48 kHz. I made the mistake because I have several albums in both sample rates, and I didn’t check. However, all hi-res sample rates work over i2s except 48 kHz. 48 kHz sampled files over USB are fine.
Listening impressions. I had a lend of a friends audioquest carbon USB cable to see if I could get USB to sound better. I also moved my Mac mini into the listening room to play audirvana over USB as a second comparison. That didn’t last long. Apart from being a bit noisy, the SQ of the Mac mini over USB was clearly inferior to the ms2 over USB. The mac mini was less detailed and more muddled. It was marched back to the office.
USB vs HDMI. I’m using the w4s HDMI cable (came with the ms2, about 1.5cm diameter, quite stiff), vs the audioquest carbon USB cable, both well burned in. It’s quite close really. The USB has nice detail and air, with more image depth (very slight). But it also has less depth to bass and a “hollowness” in the midrange. I can’t decide if that contributes to the quality of depth, but it gives a dryness to the overall sound. The cheaper USB cable (QED), rolled off the treble in comparison. We tried a third USB cable (belkin) which had great bass, but again, rolled off treble. The HDMI cables (cheap no-name, and the w4s branded) sounded the same to me. HDMI SQ was weightier in the bass, slightly less depth of imaging, but a nice even midrange tonality, and to my ears a slightly more “organic” quality.
Conclusions and thoughts: 1) vortexbox based players (like the ms2) sound much better over USB than a Mac mini (or at least my 2011 dedicated music server Mac mini).
2) different USB cables seem to make a big difference.
3) with a good USB cable the difference between i2s over HDMI and USB is minimal. I will speculate any differences may have to do with jitter, as Jesus has alluded to. The i2s output from the ms2 is apparently custom made by Rick and EJ at w4s with a dedicated clock circuit. It is in proximity to the ms2 processors, which could cause RF and EMI noise. The USB is asynchronous, therefore the clock is determined by the PWD II. I don’t know which method is best. But there is a difference and it seems to affect the SQ, thankfully, not too much.
Now… Bring on the Bryston and the Sonore…
@vortecjr I'm not much of a "hardware tinkerer", so internal mods are a stretch for me, Jesus. Cables I can do!
stereophilus, no need to mess with it internally. Substituting the external power supply for something like this http://www.sonore.us/index4.html would make a big improvement.
Jesus R
@votecjr Yes, power supply upgrade is the next step for the ms2. Could you tell me if it is compatible with Australian 240V AC? The DC cable fits the ms2?
@votecjr Yes, power supply upgrade is the next step for the ms2. Could you tell me if it is compatible with Australian 240V AC? The DC cable fits the ms2?
Yes and yes:)
Jesus R
stereophilus said: The upgraded W4S MS2 server can play into the PWD II with i2s over HDMI in nativeX mode.
Has your MS2 continued to perform wonderfully well?
Is the I2S upgrade now the standard version for the unit or is it a special order? (Does W4S use the PSA protocol for its DAC?)
@elk the ms2 works perfectly, except with 48khz sampled files over i2s in nativeX. The sound is clearly different to the bridge, but the difference is in timbre and texture. I prefer the ms2 most of the time. Interestingly, when I use the ms2 to serve the audio to the bridge to play, the bridge sound comes through.
I don’t know for sure about W4S products, but Clint did indicate to me the digital output board with i2s output compatible with the PWD II in nativeX is now standard on new units. You may have to check with him about the protocol used, I don’t know about that.
The difference in sound between the Bridge and I2S is intriguing, as is an identifiable Bridge sound. It is good to hear you remain pleased.
Thanks for the info!
@stereophilus it is now standard
Sorry to confuse everyone further, but… PWD Firmware makes a difference to the W4S. I’m referring to the issue I had with 48khz sampled files over i2s in nativeX being incompatible. When I switched fmwr to 2.41, 24/48 played fine, but 24/96 gave me white noise (it was loud too!). Prior to that I had been using 2.03.
Fmwr 2.20 gave me no issues with all different sample rates…
This is a bit weird, and probably goes against the theory that the signal over i2s has higher jitter than over USB, rather it has to do with nativeX and the firmware…