Hello Levy3,
".....use the PSA duo together with the I2S connection and hi res audio. then take the reference transport and plug it into the PTD and do the same. this way....you would be comparing the PWT and the reference transport(forsell) in their corresponding, recommended, optimal set-ups."
Sure, you are absolutely right here. Since I do not own PWD then for me (and people like me) the choice of the DAC has academic interest only - as long as its qigh quality obviously. For people who have or will have PWD, your idea will be much more interesting and more importantly, very relevant. Agree with you - 100% Sorry for miscommunication again.
All The Best
Rafael |
no problem Rafael....my original post stated that roger is very likely correct. nothing wrong or unfair about his statements. the only way it could be considered unfair is if PSA was not marketing them as being "fine" hooked up to other equipment in alternative ways. they clearly are so roger's test is as fair as any. as i stated in reply, the PSA duo is very proprietary at this point imo. this in and of itself is a negative thing for many i'm sure. i agree with your idea that selling them as a set would be the best way to go. unfortunately business's don't always do what is best for the consumer. they're after our money for the most part.
regardless of how PSA chooses to sell/market them, i think they were/are made for each other and should be paired to hear their full potential. not doing so leaves alot on the table in my eye's. at my demo, the dealer briefly hooked up an alt connection and i heard a substantial difference instantly(forgot which connection he used...sorry).
in the end....i think we are in agreement. i by no means think either PSA piece's are "the best". with my limited experience.....i couldn't even tell you what the best transport or dac would sound like. those kind of determinations are better made by folks with alot more knowledge then i(like rodger. you and many others around here). i am smart enough to know my own limitations ;-).
i just took offense to your "cry" comment. not a big deal really but here is what i was looking for in a transport only comparison. 1st...use the PSA duo together with the I2S connection and hi res audio. then take the reference transport and plug it into the PTD and do the same. this way....you would be comparing the PWT and the reference transport(forsell) in their corresponding, recommended, optimal set-ups. again...this is only what i personally would like to see/read/hear. not saying it's more fair or a better comparison. that's how i'm buying them so that's what i wanted to see.
shazam- what are your thoughts on the various media types?. have you had a chance to compare redbook, reg cd's, high res dvd, ect... thanks for the write up. look forward to more of your input.
cheers
Lev |
Hello Levy3,
Roger concluded: "...PWT itself does not sound as good as a high-end transport like the Forsell"
In response, you wrote: "...as of release, the PWT and PWD are made to work together in a pretty specific way. super high res DVD recordings, native and memory playback, I2S connection, asynchronous clock, digital filters ect..."
However, transport part of this "specific way" was replicated in Roger experiment in full except the signal was transmitted not by I^2 as recommended by PS Audio. Even if I^2 would be implemented then result for PWT, at best, could be slightly better... nothing more
If my characterization of your objection of stepping out from PS Audio prescribed protocal (as of release, of course ;--) then my deepest apologies.
As self characterized newbie try to distinquish very few, almsot impeccable observations like Roger did from bazzilion of other like above where someone stated that he examined a hansful of hi-rez file using regular USB port which is capable of 16 bit 48 kHz max transmission.
As you can see I am not looking for the budies here but accurate information which Roger provided and this fellow did not. His (probably accurate) observation I attribute in large degree to his faulty methodology and thus almost worthless. I am saying "almost" because others who use noisy computers with non-dedicated UBS port or Sonos as the source and compare to... other PS Audio DAC ( improved by Mr. Cullen or not) should be very clearly happy with his results, and its important and its useful.
All The Best.
Rafael |
Roger; does anyone have experience connecting the PST transport via hdmi into the new Meridian 621 switcher; which claims to have its new aphodizing filter incorporated; then running that back out into a digital Meridian processor. PS Audio's web page states that their hdmi interface is proprietary; and may only work on their DAC unit for optimal sound...
I am using a G-98 into the 621 switcher via hdmi; and noticed a nice improvement; but want to soon audition the PST; and want to figure out best way of incorporating it...hard to use external dacs with Meridian gear; as their processors convert most all signals back to digital anyway...thanks. |
who's crying Rafael??. the only times i saw the word "fair" were in rodger's and your post??. i certainly didn't use it or even imply it. sounds like you got a little chip on your shoulder Rafael. it appears you have found the comparison results you were hoping for =)
if you really want to use word "fair" and or "unfair"...that's fine. while the reference set-up in this comparison was configured as recommended or near optimally, the PWT was not. i didn't/won't use the word unfair but will say it was not a *good* comparison if one hopes to find out what the PWT/PWD can do. other then that....i had no problem with the comparison. what i do have a problem with is you saying me or anybody else is crying here. talk about BS! |
Just got my PWD last night, and here are my initial impressions.
I have two source connections, a Sony Viao laptop (via USB) for playing a small handful of hi rez files I have and a Cullen Circuits modified Sonos (via Coax) with a 96k upsampled output for all my redbook content. Previously I was using a PS Audio DL3 with Cullen Circuits Level 3 mod. The Cullen Modded DL3 reached much deeper and was much more detailed/cleaner than the stock unit. I preferred it by a wide margin to the Benchmark DAC 1 (too analytical sounding for my tastes) and the stock Slim Devices Transporter (lacking in energy for me). I'm using Nordost power and speaker cables, Transparent Audio interconnects, ProAc 1SC speakers, and a Manley Stingray integrated.
Right out of the box, the PWD is immediately even deeper and wider than the moded DL3 - a bit of a surprise, but a welcome one. The accuracy and detail impressed me too. There were things I was hearing in some of my favorite recordings that I knew were there but wasn't hearing on the DL3. Thinks like the resonation of a drum hit or the pluck of the bass string that got muddied or covered previously was there now. of course, this was especially evident when I went to my hi rez recordings via USB.
The thing that has me the most excited - and was not something I expected - is the lack of fatigue. On first listen, it seemed more laid back than the DL3 and I was worried it wouldn't be lively enough for me. But the more I listened the more I realized it is just a higher quality sound. I listened for about 4 hours with almost no fatigue - something I could never do with the DL3. In retrospect, I think I was interpreting the brightness of the DL3 as the vivid sound I like when in fact I just lacked quality. Because I could hear more, I felt more involved with the PWD than I ever did with the DL3. Assuming that trend holds, I'll be very happy to be able to have more extended listening sessions.
I didn't mess with the filters much, preferring to just let the auto filter do it's thing. However, flipping around them I can clearly hear how someone may find a preference for one over the other to suit their tastes. One rolls off the high end a little quicker, one does a little better job of knocking down the clutter you get with a lot of instruments in the mix, and so on. I might even end up developing a preference based on the type of music I'm playing. Let's face it, I listen to acoustic jazz for different reasons than I listen to pop, prog rock, or classical. And yes, I listen to all of them.
I'm looking forward to eventually replacing my Sonos and Laptop with the Bridge when it comes out. It will probably help me eliminate the last bit of glare and hash I get from the Sonos. And I've never been able to get the AISO driver properly configured for my laptop, so I'm always wondering if I should be getting better there as well.
All things considered, I'm extremely happy with my first few hours. Talk to me in a month and hopefully I'm still giddy. |
i agree Rodger. if they're gonna sell them separate and make marketing statements regarding alt set-up's...your comparison was 100% fair/valid imo.
just wasn't the camparo/information i was looking for specifically. not knowing alot about transports and dac's in general, i was hoping to see some real world comparisons with the duo against other similar set-ups.
btw...funny you mentioned the transport sound when opening/closing. that was the single biggest negative i remember from my demo.
thanks again for taking the time to report
cheers
Lev |
Hello Roger,
Thank you very much for your experiment. It provided the best assessment of PWT capabilities. The Forsell Transport is one of the best around
Thank you again
Regarding cry that it was not fair - because PWT was designed to work together via I^2 - its pure bull s...
1 - as you said if that would be the case then PS Audio should ethically to sell PWD separately as well as PW Player (i.e. P+D togeter for about $4.5k).
2 - Assuming that in PSA implementation by I^2 provides no or minimum jitter one can extrapolate that results would be better with I^2 - but by how much??? Day/Night? I doubt. Everybody who dealt with digital clocks will tell you that better clock improves sound and noticeably and that's all.
3 - I am not familiar with DACs you used in this experiment but I will assume that they are on the same level as Forsell. If so then
a)Their jitter suppression must be superb thereby futher reducing the possible difference between I^2 and S/PDIF inputs.
b) their power supplies, their analog output stages would be much, much better then relatively cheap PWD output stage and therefore sound should be much better too.
4 - This is my pure speculation and I could be wrong. If I^2 is so much superior to other methods of digital signal transmission then why only PS Audio, company with so far mediocre ("non remarkable" more polite word if you wish) products - as compare to the level of Forsell product - exclusively introduces it. Why not Wadia, Esoteric and few others - accepted leaders for decades in digital world. Must be a good reason and its not the cost, nor technical expertise nor luck of experience. I don;t know the answer but this fact bothers me a lot
Thank you Roger again. Wonderful experiment with multiple observers.
Rafael |
If the PerfectWave transport can only 'shine' if it is connected via I2S to the PWD, why then did PS Audio separate the two and sell them separately for $3k each? I have evaluated the transport for what is is against another unit with the same intended funcionality and I think this is fair. The fact that PS Audio has chosen not to give more emphasis on the quality of the PWT's S/PDIF and balanced digital outputs is unfortunate, but it is what it is.
Yes I will also evaluate the hi-rez DVD-R music material and try to borrow a PWD before I will come to a final conclusion.
And Levy, you may be very happy with the PW combo when you integrate it optimally into your system (as you describe). All I am saying in my post/comparison is that the PWT itself does not sound as good as a high-end transport like the Forsell.
Good luck and share your impressions when you have the combo at hand. |
thanks for the info Roger. i've got the duo incoming with only a short in-store demo under my belt. was wondering why you wouldn't do a comparison of the PWT with the PWD?. i'm pretty close to a know nothing regarding alot of this stuff, but have read almost everything regarding the PSA duo. just finished the owners manual today. the recommended way to run the PWT is with the PWD via the I2S cables, then directly to the amp. pre-amp is ok if you must (Mr M called it the best way in the video).
again....knowing little about dac's and transports in general, i might have missed something here?. PSA itself might share some of the blame too?. they have made statements implying "it's fine" to hook these piece's up in a variety of ways. however, from what this newbe has gotten out of all his PWT/PWD research is this. as of release, the PWT and PWD are made to work together in a pretty specific way. super high res DVD recordings, native and memory playback, I2S connection, asynchronous clock, digital filters ect...all working together. we'll have to tune in later for additional compatibility (bridge, FLAC, folder access ect...). right now it seems very proprietary to me at least. if the point of this comparison was to prove/disprove PSA's claims of compatibility/versatility ....then i understand the set-up and reason behind it. your judgments are very likely spot on imo. no doubt in my mind that at this point when compared by itself, the PWT couldn't out-shine the Forsell.
it does seem that the set-up available didn't let the PWT "do it's thing". to do so it would need to be hooked up as recommended. that's how my demo was set-up and it went fantastic. plan on hooking it up the same way when mine arrive (with the PSA hdmi silver I2S-12).
kinda like trying to re-create a dream.
wish me luck.
cheers
Lev |
I'm not sure if PWT best quality will shine with DACs other than the PWD. I thought the main selling point for the PWT was its mating with the PWD via HDMI I2S connection. A recent review by a British mag showed its SPDIF and USB were inferior to the HDMI connection. Seems like you need to compare the PWT/PWD combo as a unit, lest you lose the synergy. |
Here is my experience with the PerfectWave transport (PWT) that I received a few days ago.
Nice and well built piece although the drawer makes an awfully cheap sound when it opens/closes. The touchscreen is a nice feature but with the unit I have received it flickers once in a while (intended?).
To evaluate the sound quality of the PWT I compared its music presentation with my 2-channel reference transport/Dac system consisting of a Forsell Air Reference MarkII transport and an Audio Synthesis Dac2 D/A converter connected to a Meridian G 68 XXD pre/pro. Amplifiers were Krell KSA-300S, speakers Apogee Divas and cables NBS or Transparent Audio Ultra/Reference. The power cables for the two transports were matched and provide balanced power from an Equitech power supply (50amp dedicated circuit). For the comparison of the transports I used the same Redbook CDs with Jazz, female opera singer, classical piano, violin, whole orchestra, and choir acapella music. The PWT was connected to the pre/pro in two different configurations: I first connected it via NBS Master S/PDIF digital cable with a digital input of my Meridian XXD pre/pro to provide the D/A conversion (24bit/96kHz) dacs. Alternatively I connected the PWT via an NBS Pro balanced digital cable with the Audio Synthesis Dac2 which in turn was connected to the Meridian pro/pro in the same way as the Forsell transport. So alternative one was "all digital" from transport to digital pre/pro, alternative two included an external D/A converter in addition.
For both pathways the PWT sounded detailed and with a solid lower range. Voices and solo instruments were presented with good texture and placement. The overall impression of the sound was on the bright side and not very lively. It was clean and precise, but somewhat 'sterile' (esp. live recordings). Unexpectedly the soundstage and the volume of the reproduction increased when the path with the additional external dac was taken.
The direct A/B comparison of the PWT with the Forsell transport with the same diverse music material revealed for both setups that the PWT cannot reach the sound quality of the presentation of the Forsell. The Forsell transport presents voices and instruments more solid in their position and more natural in their texture. There is more ambiance/detail in the presentation, it is significantly more lively and engaging. The differences were not subtle and an audience of several audiophiles could pick them up in a blind A/B session easily.
Although the PWT is obviously a very good sounding transport it is no match for the transport (Forsell) used in this comparison as a reference. |
I got an answer from Ryan Conway at PS Audio:
"The DL3 will take virtually any two channel PCM you can feed it as follows:
USB = up to 16/48
Toslink = up to 24/96
Coax Digital = up to 24/192"
So I can hear hi rez today (well, once I figure out how to get 24/96 out of my HP laptop. No Toslink or coax on this bad boy. :-( ) |
i'm jumping in the lake without dipping a toe first. have been looking to upgrade my cdp and eyeballing DAC/Transports for a while. the PS Duo just popped onto my radar last month. a set was made available the other night (right after i posted above), so i jumped on it. should have mine next week. much rather waited a year for some debugging but hey....it's not a pacemaker or baby crib. i'll survive if it takes a crap.
with everything i've read and 4k with trade-in program....it seemed like the thing to do.
looking forward to it
|
Best demo I've heard of the PWD: a decent CD player and the PW duo connected to the same pre/amp/speaker setup with two copies of the same album. We did some A/B listening flipping between the two and got a real sense of the differences. Much smoother and a bit better stage I recalled. But most importantly, it was the least "digital" sounding digital device I think I've ever heard - and that is what sold me. Seems there is something to the new filters.
My PWD just arrived at the dealer today (just got the call). I think I'll take my source in (Cullen modded Sonos & DL3 with Cullen level 3 mod) and do some listening since I'm swapping out my DAC as part of the deal. We'll see if they let me do it. |
i'm considering the PWT/PWD too. just gave them a short demo at a local audio shop. sounded really nice but then everything i hear in a demo room sounds really nice. have heard alot of positive comments(mostly from folks selling the product) but would like to hear more from owners who have some extended "real world" use with the pair.
look forward to hearing and reading more. |
Hello,
I will receiving this new exciting product in a few weeks. My dealer says I in for a real treat.
He states that the sonic presentation is truly non-digital sounding and extremely enjoyable that most people can live with the PW duo until the end of time.
I am hoping owners may share their opinions about the sound performance and some tips using this new PW.
Thank you,
Terry |
Does the dac sound better single-ended or balanced? I'm still waiting for my PWD to arrive. During the audition, it was connected via a balanced interface, but I'm not sure there would much of a difference between really great single-ended ICs vs balanced ICs. I'll use balanced just because it's available and I have some good balanced cables on hand. One thing to consider is the fact that balanced gives you a 6db gain so if you plan to use the PWD as a preamp that may give you a little extra headroom on the volume. |
Does the dac sound better single-ended or balanced? |
Will the PWT/PWD be able to be controlled and your music files accessed with an I-Pod touch? I had read this someplace but haven't heard it discussed lately? Or would this be connected with the yet to be released bridge? This will be implemented via the forthcoming Bridge device. At one point there was talk about interfacing with an iPod/iTouch device(s). From talk on the PS Audio Forum, it now sounds like PS may take a different approach. As of now it has not been decided (or at least made public). |
Will the PWT/PWD be able to be controlled and your music files accessed with an I-Pod touch? I had read this someplace but haven't heard it discussed lately? Or would this be connected with the yet to be released bridge? |
In any case, I am 99% sure it only deals with 16 bits, but I haven't queried the PS Audio folks yet to get the real answer. Ahh...does this mean the 96 and 192 kHz up-sampling modes are actually 16/96; 16/192? That doesn't seem right?? I guess it won't really matter come December!! Ironically, the 24/96 files that I feed the Duet-DLIII do sound superior to the majority of my Red Book files (just think what they'll sound like via the PWD). |
I believe the DL-III upsamples as a way to reduce jitter. Unfortunately, it does not offer a "native" mode of 44k(like the PWD will.) In any case, I am 99% sure it only deals with 16 bits, but I haven't queried the PS Audio folks yet to get the real answer.
I'll be in the Denver area next week and plan to visit the factory, so hopefully can resolve all my questions there. I'll post my findings.
Cheers. |
Kartracer,
Since the DL-III is an up-sampling DAC (with the choice of either 24/96 or 24/192) I assume that when the SB Duet feeds it a 24/48 signal (from 24/96 files which SqueezeCenter down-converts to 24/48), that signal is automatically up-sampled it to either 24/96 or 24/192 depending on the setting you choose? In other words, we're not really hearing what 24/48 sounds like natively, we're hearing it up-sampled to 96 or 192 kHz. Therefore, via the Duet and DL-III you and I cannot hear what native 24/96 really sounds like. I (think) what we get is a weird hybrid (24/96 converted to 24/48 and then reconverted back to 24/96)??
Once you and I receive our PWDs we can feed them up to 24/48 natively via our Duets, but that's the limit. We'll have to wait for the confounded Bridge to realize native 24/96 and higher. |
I'm 99% sure the DL3 only takes in straight Redbook on the SPDIF inputs (16/44.1) USB is a different story, but I'm not interested in using USB. I want to have some higher than Redbook FLAC files on my laptop ready to feed the PWD when it arrives, so I'm still trying to figure out how to do that (besides USB. But if that's the only way, oh well.) I'm thinking of buying a couple 24/96 albums from HDTracks to use. I'll post this question on the PS Audio forum. |
Kartracer:
Since you have the SB Duet, you are undoubtedly running the SqueezeCenter software, which will down-convert 24/96, or anything higher, to the Duet's native 24/48 output. Im not sure if SqueezeCenter up-converts 16/44 to 24/48, or if it simply streams the 16/44
anyone?? Now, what I don't know is what the DL-III does with the 24/48 signal. It will depend on what it supports natively (maybe the PS Audio website has this information available), but remember it is an up-sampling DAC. So, if you have the DAC set on 24/96, it probably takes the 24/48 signal (and/or 16/44) and up-samples it to 24/96 (I assume this is the protocol). In native mode, the PWD will support up to 24/192 without any up-sampling (i.e.: it will support the Duet's 24/48 "signal" natively).
PS says that the USB on the PWD, which supports 24/96, runs straight to I2S and is one of the best USB interfaces available, but the Duet doesnt support USB so you and I will have to run S/PDIF. Once the Bridge arrives, the best interface between it and the NAS will be Ethernet (or wireless if they go that route, but it sounds like theyre still undecided), effectively eliminating the need for USB or S/PDIF. The Bridge will also go directly to I2S (the PS protocol is to place the Bridge/Lens in the chain prior to the analog conversion, at which point it is output to I2S with asynchronous clocking). |
How are you feeding 24/96 files to the DAC? Are you using a software player that downsamples them to 16/44? Tell me how so I can try it!
Thanks. |
Actually, the Duet will support up to 24/48 natively. I'm not sure about the DL-III (I know it up-samples not sure about native though)?? I do know that the 24/96 files that I feed my Cullen-modded DL-III via the Duet all sound superior to my Redbook. |
I'm going to trial the PW DAC with my Duet and eventually pick up a NAS when the bridge is out ("Has anyone seen that confounded bridge" - Led Zep) Using the Duet is much more convenient than getting off the couch, turning up the lights and digging through the CD drawers to find the next selection.
I now have the Duet feeding a Cullen Stage 4 PS Audio DL3 and it sounds pretty darn good, but it won't handle any rez higher than redbook, hence my interest in the PWD. It will be interesting to compare the two DACs. |
no USB on the Sonos - so SPDIF it is. |
Shazam,
I'm still waiting on mine too. Like you, Im hoping for a wireless Bridge, but as long as the remote control interface is stiller (which Paul indicates that it will be) I can live with an Ethernet connection - which might even enhance the transmission quality. It would be another freakin' wire to string across the floor though.
While youre awaiting the Bridge, what will interface your Sonos and PWD with USB or S/PDIF? |
Paul M of PS Audio said he believes the price on the bridge will be in the $500 range. But that is subject to change if they change the design (which is possible given the current design lacks wireless - an unacceptable condition in my eyes).
I'm still waiting for delivery of my DAC - no word on when that will be. Not even sure if my dealer has one yet. |
I'm thinking of taking the same road that 2chnlben is taking. The Powerwave DAC seems to be the answer for what I'm looking for and I'm very curious about how the bridge will be implemented.... AND how much it will cost. If they keep the cost down it will probably be a no-brainer |
Distributor representatives hit the road with products for auditioning in June. Thats how I auditioned the series at my local dealer. The series that I listened to extensively was just superb. While the HD files and DVD disc (containing HD files) did sound exceptional, I found that Redbook playback was the best that Ive heard to date. |
I think very few people have heard them, just beta testers. Their impressions on PS Audio's forum have been generally quite positive, with three caveats. First, the Transport/DAC supposedly sounds best on high-res formats that are not widely available commercially. Second, the units supposedly sound best plugged directly into an amp rather than a preamp, which creates a problem if you listen to vinyl. Third, the products may not be completely bug-free at this point and some of the functionality (like wireless music server capabilities) has yet to be developed and is not scheduled to be released until the end of the year. |
Shazam,
That approach wouldn't surprise. Looks like PS is going down the high performance/proprietary architecture/customer lock-in route more like Sonos with this product line from what I can see.
The plus to this is that the stuff you buy from PS Audio should perform very and be easy to use together.
The down side is that you may be locked into PS Audio for upgrades and add-ons that are compatible down the road and may pay more for what you get as well.
Kind of like the Apple computer road that many gladly go down. |
The buffer in the PW Transport and PWD Bridger is a RAM chip very similar to computer memory.
Also, they haven't decided if the Bridge will be wireless or not yet (I think it might have been another thread someone asked about that). They are considering doing something like Sonos does where you can plug a device into the router and create their own network mesh that doesn't bother depend on the limitations of standard WiFi.
This from the horses mouth last night (Paul of PS Audio). |
Any other beta testers besides Mr Darby? Comments? |
Tbg -- From the owner's manual: The memory for the PWT is not located in the rear SD card as is commonly assumed. The rear panel SD card holds the cover art and song title information as it is acquired. In addition, the SD card is used to program new firmware in the PWT. The SD card is flash memory, of course, but as this indicates it is not what is used as the buffer memory for the music. Regards, -- Al |
Almarg, I think the Memory Player uses flash memory or claims to. I don't remember whether it retains its information, however. What is in this memory can then to downloaded to the hard drive. |
I suspect that it is not flash memory which is being used, but rather dynamic RAM (random access memory), similar to computer RAM memory except with much less capacity. Hard drives and flash memory retain what has been stored when power is turned off, while dynamic RAM does not. However, RAM is much faster, and also cheaper and more compact. Also, flash memory has a limited number of write cycles it can handle before failing, the number being fairly large but potentially a significant factor in cdp or transport lifespan. And it requires sophisticated memory management algorithms to minimize that limitation.
In principle a transport could certainly be designed to utilize either a hard drive or a flash memory, but it would add to the cost and complexity, without providing added value for many or most users.
Regards,
-- Al |
2chnlben, if I understand this right, the Perfect Wave merely reads the cd into flash memory and then replays it. Why this is then not added to a hard drive seems unfortunate to me, but I can see why a perfect copy would be better than relying on the cd player to get the data just in time to send it on.
I have not heard a demonstration of hard drive to flash drive for replay versus straight from hard drive. Perhaps this does make a difference. |
There are well known and praised digital front end systems on the market listed at $68,500, $29,000, and
I dont know off the top of my head what MBLs best are listed at. Now, we have the Perfect Wave system listed at $6,000. Comparatively speaking, this cannot be considered over-priced. I just bought the PWD for $2,000 (plus trade in). I have written about what this system sounds like. It does not deserve comparison to the DACs that I am familiar with in the $5,000 and under sector. The PWT/PWT should be compared to the super high-end digital front end systems on the market. It may, or may not hold its own with such products, but I can verify that it is superior to most of the well mentioned systems. Personally, I have opted for the forthcoming Bridge instead of the PWT (transport). To me, a high-end music server makes more sense why bother with individual CDs
|
i find it surprising that ps audio did not use one of three 32 bit dacs. perhaps one of the dacs which incorporates such a chip will give ps audio's productm competition, e.g., the buffalo dac. |
Shazam -- Yes, it makes (bit-)perfect sense! Thanks very much.
So the benefit (or at least a benefit) of the large cache is that it allows time for the large number of retries which may be attempted, at least with marginal disks, which in turn would essentially eliminate the need for error interpolation.
One question that brings to mind that I would want to assess is how well-controlled the acoustic noise produced by the drive mechanism is, considering that it is running at considerably faster than 1x rates, and it will occasionally shuffle around and backtrack for the re-reads. I'd assume that is addressed well in the design, but it seems like a relevant question to raise.
Another point relating to their descriptive literature, though, would be that claims that no error correction is used are probably mis-stated. EAC's site, in fact, states that with the EAC software "if there are any errors that cant be corrected, it will tell you on which time position the (possible) distortion occurred, so you could easily control it with e.g. the media player." In other words, I would envision that the PerfectWave Transport does away with the combined error correction/error interpolation provisions that are provided by more conventional cdp drive units, but then makes use of the Reed-Solomon error correcting codes in its own processing, to correct all errors which can be bit-perfectly corrected. There would seem to be no reason not to do that. The difference relative to a conventional cdp is, if I am correct, that no error interpolation (i.e., estimating of what the sample value should be) is performed -- that is what is eliminated by the multiple re-reads.
FYI, re your statement about the PW using EAC, one of the pages at their site indicates that their MREC (Multiple Read Error Correction) process is "similar in concept to EAC."
The benefit of all of that, of course, will vary with the physical quality of the cd, and perhaps the age and condition of the laser. But there is no question in my mind that the I2S interface approach is vastly preferable to the conventional interfaces that multiplex and then de-multiplex clocks and data, and that is perhaps the most significant advance provided in this design.
Thanks again for the good explanations.
Regards,
-- Al
|
Mostly, yes. I'm still of the opinion that the design is a very good one. if you like the sound of the DAC, it should work well.
I'm not convinced yet that, other than support for higher resolution, it is leaps and bounds above other player or in particular server options at least for redbook CDs.
Isn't it a bit ironic the prices charged for "good" CD transports when a computer is seemingly so much better equipped and cheaper, at least nowadays?
I suppose when CD players first came out the technology needed to read and forward the data correctly was pricey, but I am certain it is not nowadays. |
I agree that the literature is poorly written and doesn't explain it well. I actually spent a good 30 minutes in the PS Audio room at the RMAF last fall chatting with Paul and others about the technology and I think I understand it pretty well.
A typical CD player does have a buffer, but it basically amounts to a fraction of a second in most cases (good players will have a second or more). This is to allow for the variations in spin speed and movement of the laser changing the timing data being pulled off the disk. So long as the data pull stays within the margin of the buffer you are fine in this regard. But pull too much data and the buffer doesn't have room for it (buffer over run). Pull not enough data and the buffer empties out and the digital stream stops (buffer under run). This is basically the second paragraph Al quotes above.
The Perfect Wave has a significantly larger buffer which provides much more room for error. Let's say the PW holds a minute worth of music and begins to generate the digital stream when it is half full. This gives the laser 30 seconds either way to keep the buffer filled with enough data to keep music going.
The second part of the equation, however, is the important one. A CD laser is a single pass reader and uses error correction (ECC) to try to clean up dropped sectors - it has one chance to get it right and one chance to clean it up (with imperfect correction data no less). The PW laser operates like a computer drive, which will read a sector multiple times if necessary to assure it has the data right. If you read up on the technology in the ripping software Exact Audio Copy (EAC), you will get a better understanding of the principle at work here. In fact, if I heard Paul correctly, the PW actually uses EAC to read the disk and generate the buffer.
The CD player has to spin at a constant rate that basically reflects the stream rate (this is "1x" speed in CD-Rom speak). The Perfect Wave can spin up significantly faster because it's building a significanlty bigger buffer data file (think a CD-Rom that runs at "16x" or "24x" speed). This is how, when they demo the player, they will eject the disk after about 30 seconds and the music continues. The PW is capable of pulling the data much faster because it is acting like a computer drive to create what amounts to a file, which is then turned into the digital stream.
Finally, the PW generates the digital stream like any other CD player, but if you take the stream out to the PW DAC, it keeps it in I2S format all the way to the DAC chip. A traditional transport device must convert the stream to a different format to accomodate Toslink, SPDiff, or USB, and then the DAC converts it back to I2S to send to the DAC chip. By doing this, all sorts of timing errors and re-clocking problems are introduced which creates jitter and hash. This is where we spend money on external re-clockers (like the Pace Car) to better manage this process. Using the PW combo eliminates this problem because the data is always in the optimal I2S format.
Does that make sense? |
I am a PS Audio dealer and am anxiously awaiting the demo set to be brought by from the rep firm who is local. When I have actually heard the set in my system I will give a report based on comparison to my current reference room demo set of the Bel Canto dac3 and CD2 combination. |
Shazam,
I was under the impression that most optical drives, audio or computer, do rereads of data normally when errors are detected? I didn't think most modern CD players were one pass only because frankly there would seem to be no reason for them to suffer with that limitation. |
Thanks for the good explanations, Shazam. You should replace whoever writes their literature! I do agree that the file-based read, and the I2S interface (which avoids multiplexing the data and clocks together) sound like excellent approaches. Hopefully, as you say, the I2S approach, or something similar, will be adopted by others. What I was taking exception to as misleading, though, is exemplified by this paragraph at their site, in the description of the transport: In a standard CD player or Transport, the master clock is synchronized to the optical disc reading mechanism. This means you are basically relying on a mechanical spinning mechanism and all of its correction systems to give you a perfectly stable, fixed clock to feed the DAC. It does not work and it is not stable.
Here's the problem. Optical disc readers are constantly changing the rate at which the data is coming from the disc. Sometimes it comes faster and sometimes it comes slower than the fixed speed of an asynchronous clock. If that data is coming in faster than the clock, you get a traffic pileup and the system crashes. Too slow and nothing comes out.
The Digital Lens has a large and smart memory storage buffer. It's big enough to handle any speed variation of the optical disc reader. That would appear to indicate that in other transports and players the timing of data to the dac is subject to fluctuation identical to the fluctuating timing of the data coming off of the disk. It was sufficiently misleading, in fact, to have apparently misled one of our most intelligent and experienced members, with whom I was having the discussion above. :) Best regards, -- Al |
