In my opinion, the answer is no. I have listened to the Mac+DAC combo vs. the cdp and the cdp sounds fuller with more dynamics, present and body.
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Your question is even more difficult than you may think. Unfortunately the axiom "Everything matters" is as true with computer-based playback as it is from more "conventional" sources. With a standard Mac using USB with a spinning hard disk, itunes, and the Mac OS you may get one result; with a solid state disk, different software, or a different interface you may get a completely different result.
Spend some time over at Computer Audiophile and I think once you get past the overwhelmed feeling you'll begin to develop a better sense of the issues and (hopefully) some direction. I'm in the process of doing that myself.
cheers for sharing, my friend's gone through the ripping and enjoying his download, and he too is in the process of upgrading his software, last time i was around his place he was using fubar? So I was just calculating if the cost of Cx7e mp could get me the DAC+Mac then I'm more inclined to the DAC.
I agree with you Aggielaw, everything matters!
I'm also concerning the fact that I'm moving back to the UK in about 3 years time, have to go through the hussle of converting the voltage to 220, so i might as well get the cdp and sell it. It's a tough one!
just read some stuff from audioasylum Charles from Ayre insisted that the dac is on par with cx5e mp, cx7e mp only sounds better cuz the dac is not fully broken in.
And also to maximise performance with dac, he said it's better to upgrade up to 8GB RAM, there are tests about Macbook pro sounds much better than mini+ with software like Amarra it makes top notch sound. Oh he mentioned pluggin the dac in power filter as well. So there you go.
I have a QB-9 and love it. I also have a Esoteric DV-50 and if there are any differences, they're too subtle for me to hear and rely on memory.
I also keep seeing the thing about the Mac and adding the extra memory changing the sound. (Could be from one source and repeated here and there). If adding memory does in fact change the sound, there's something "broken" on the MAC. It doesn't take a lot of computes with today's, or even yesterday's, hardware to take a PCM stream and send it out USB. The MACs problem could be sloppy software design unpacking lossless compressed music files and generating the PCM stream. Although I still can't think of a way this would change the actual output data from what was originally used when compressed. There's no variables, it's a deterministic transformation. I'm guessing it's "faulty recollection" that happens way to often in audio if not broken software. Also, all this assumes the MAC software does not process the resultant PCM stream before output or rely on some sort of system timing to generate the PCM.
My 1GB memory based Samsung netbook and external USB disk drive running XP sounds exactly the same as my Quadcore 6GB DDR3 based game system. And I'm not a Windoze fanboy. Microsoft has generated some of the sloppiest software known to man. :)
I haven't heard the cx7e, but I listened to the 5XE and the QB-9 with B & W 803D speakers and Ayre K5 amp and preamp. I also heard the qb-9 with Wilson Maxx speakers and Audio Research amps (sorry, don't know which ones), the 5xe with Wilson Sasha speakers and agree, to some extent, with Cerrot's opinion above. I actually did like the qb-9 though, if the right equipment was matched with this dac I think it would sound very good. Only when comparing with a more expensive cd player did it show it's weakness. With the Ayre amps and B&W speakers, it was warm sounding with good detail, nice soundstaging. Of course this was my opinion, others may not have liked it, but I thought for the price it was very enjoyable to listen to. Sandra
To my ears, in my system, the CX-7eMP and QB-9 are pretty close overall. The QB-9 sounds a bit more open and immediate but also a bit smoothed over, perhaps a hair less dynamic. I'd call it a draw, overall. It's impossible, however, to farily compare the two because the computer *must* be part of the equation for the QB-9 and there are boatloads of variables that affect computer playback (all the hardware combos, OS, msic player, power supply and on and on). I still need to try 1) different music players (eg, Jplay, JRMC, etc); 2) upgrade USB cable; 3) linear power supply; 4) SOtM USB card. I'm hopeful that the QB-9 will outperform the CX-7 after I get the computer "optimized". In the meantime, the CX-7 can't play hi-rez material even tho' it is far easier to use than ripping/tagging/organizing/backing-up music files.
In my system, my QB-9 is better than my C5xeMP.
And it's outperformed other CX5s & CS7s (and for that matter - every CDP regardless of cost) on various locations where I was voicing a system.
I believe (not stated as fact, just opinion) that much of this is so system dependent - cables, computers, optimization of computer & files, music players, etc.
So I'm not sure if any of our opinions count for much except how the components worked in THAT system.
Hello Doggie, the way it was explained to me, the QB9 DAC was derived from the C5's DAC, the USB input was added to make the QB more universal ( sell more unit's ). The DX was made even more universal with it's video capability. This came in person from Ayre's X Steve S. now with AudioQuest.
For what ever it's worth, I brought both the C5 and DX5 home for a lengthy audition, the DX had a bit more drive but the C5 had musicality and a sense of pace in a precise way that the DX could not match.
I feel all the above are beyond reproach in there price category.
Having lived with the QB-9 for a couple of months now, I still think it has pretty similar SQ on redbook material. However, I have a couple of hi-rez downloads now (most notably, Ani DiFranco's Reprieve) that make my system sound better than it ever has including my very best vinyl examples. The texture and warmth of vinyl is combined with the the completely silent backgrounds of CD. Wow! More of this, please!
I have the latest qb-9 and love it. It is better IMO than the CX7emp and the CX5emp that I owned and easier to manage your collection.
I haven't had much luck with hi-rez downloads, at least from HD Tracks. Most were missing major information and after a dozen emails was urged from support to beware of the flaws associated with "popular hd files."
I was able to get a credit to download some 192k files and find they are not really that good either.
"I haven't had much luck with hi-rez downloads, at least from HD Tracks."
So, these were missing metadata?
I've read some negative comments about HDTracks but have, so far, been quite happy with my purchases and customer support from HDTracks (about 10 albums). The aforementioned Ani DiFranco is from HDTracks. The best sonics I've heard from any album of any format (hi-ez, CD, vinyl, FM) on my system.
Rufi, I don't know what you mean by missing metadata but they sounded open and dynamic but edgy. I can't handle edgy when good digital is smooth and deep. HD Tracks rep said their downloads are hit or miss in this department.
Seems like quality control or attention to some of the details might be helpful on their site.
If the QB-9 loses out to the C5, it's a possibility that the computer system wasn't fully performing.
I'm not saying that it wasn't - but it is a possibility.
It took awhile before I got my MBP and QB-9 to move beyond the C5's performance.
It wasn't the equipment in my case, it was the learning curve that I had to climb.
So I am not sure they can be directly compared as there are so many variables - it's not simply one or the other - at least it wasn't for me.
"it's a possibility that the computer system wasn't fully performing"
Could be, but I'm finding my QB-9 more or less "immune" from computer-side tweaks. I suspect the asynchronous USB operation and galvanic isolation make it so that futzing with the PC is not neccessary to get great sound.
"The qb9 was no where near the C5"
My guess is that the QB-9 was not fully broken in. On another site, Charles Hansen opined that the C-5 and QB-9 are neck-and-neck sonically.
Not really familiar with the QB-9 however I can say without a doubt that the Wavelength Cosecant is superior to the C5xeMP which I used to own. My brother says it is no contest vs. the C7 which he also owns.
As you may or may not know, the QB9 uses the proprietary Wavelength asynchronous USB technology - but I've heard from several people that the Cosecant is far, far superior - although of course it does cost more.
If I were in the market for a digital source I wouldn't buy a CDP - I do believe that the technology is on its way out and service on transport, laser etc is likely to become difficult in the coming years.
Do not use any of those connections or USB DACs, sell your CD player and go discless. The sound will be far superior. A LINN DS unit is a much better sounding solution in one box, all controlled from an iPad and get rid of the CD player totally. Files would be sent via CAT5/6 from your PC or NAS and controlled in your listening chair with an iPad. Having any other connections (USB, SPDIF converters, etc.) are just mucking up the sound. Access all your music at better than CD quality once ripped with dbPoweramp into 24/96 or 24/192 FLAC or WAV files. The LINN Akurate DS will beat out CD players in excess of $10k.
With all due respect Audiofreak32 you are giving your own opinion. If there were one interface which was unquestionably better than all the others then that is all that would exist. There is by no means any kind of consensus here. Asynchronous USB DACs can sound great and do have some sonic advantages in a well-implemented design.
i wouldn't put too much time into his responses, almost every DAC thread has his name on it mentioning the same LINN DAC's as significantly better than any other. I think he's vested somehow...either dealer, importer, or employee.
Either way it doesn't really matter and detracts from the thread of comparing the qb9 to the c7xe.
I have not heard the c7xe but have had the qb9 in my system at one point. I'm definitiely partial to computer based front ends now so on connection options only i would choose the qb9 over the c7xe. I believe shy of the dx5 though the qb9 should employ the best Ayre has in their lineup.
Thanks for your input Jcote. Audiofreak certainly has his agenda, whatever the reason.
Isn't the DAC in the DX5 the same one as in the QB9? I always kind of thought of the DX5 as a C5xeMP and QB9 in one chassis.
Like you I am committed to computer audio. To my ears, my Mac mini through Wavelength Cosecant has been a revelation in digital audio - my first digital front end that can give analogue a run for its money - and that includes my previous Ayre C5xeMP player.
And it's so nice (albeit potentially quite expensive) to be able to download high res albums in minutes rather than having to get SACDs shipped from online dealers.
As I said, I heard the Linn servers at a show and was underwhelmed but don't feel I have enough experience with them to have an educated opinion - hence I would never post anything about them unless specifically asked or challenged. You, on the other hand, have basically dismissed all USB DACs as inferior but provided no evidence that this "opinion" is based on anything tangible.
Now, for the last time, I ask that you defend your disparaging comments about USB DACs with a list of ones you have tried that have led you to your conclusions.
It would also help if you could provide a technical explanation of why a USB connection is inferior since you talk as if you know this to be a fact.
Educate us please!
yeah Audiofreak32 seems to rub people the wrong way a lot & he's done that in one too many threads. He (it does not look like it's a 'she') indulges himself in this audio forum but provides no useful information (which the very essence of being involved with any audio forum - if you have some info, share it with others so that as many of the audio community will be better off. Long-term it will make for a better educated audio community & will raise the bar for manuf & listeners alike). But Audiofreak32 is far too obstinate to get that concept....
I'm not sure that I can contribute much here but here is an attempt:
From a very detailed engineering article I was reading (it's an old article in that it's 10+ yrs old but it clearly shows some of the hurdles that exist in the USB format as used for data transfer in an audio application. just for this sake, this article is useful) here is a short cut & paste:
"There are four USB transmission modes (please see Table 1). The two of those that are used for sending large quantities of data are (1) Isochronous Mode - A fixed number of packets is guaranteed to be sent and received. This mode is used with multimedia data such as images and audio. (2) Bulk Mode - A fixed quantity of data is sent at one time. If for some reason some of the data, is lost it is resent.
For data storage or printer applications the bulk mode is best because speed is of utmost importance and, through retransmission, data errors will be eliminated. But for audio data, real-time transfer is even more important than occasional missing data. (Noise is more tolerable than interruptions in the data. Of course pops and clicks are intolerable, but even more unpleasant is an intermittence of the data.) In this case, the isochronous mode is used. In other words, a real-time transmission scheme, with no re-sending of packets, is used for audio data, which streams from the PC in an RS-232-C-like manner.
USB is Clockless, Differential, Serial Transmission
It is not our intent to fully discuss the USB specification here. (Please refer to sister publication, Interface, March 2000.) USB 1.1 is a 12 Mbps bi-directional, serial bus, which is connected with 4 conductors....
Two of those conductors are power (VBUS) and ground (GND). Information is transferred through the other two: 1) D+ 2) D- Since there are only two data lines, only four states can be used for data transmission.
It follows that there is no explicit clock on the USB cable (this compounds the problem). Rather, the signal is restored based upon the intervals between edges of the data. In this type of digital communication, if the sender uses a perfect clock to create the signal, and the receiver uses a perfect clock to interpret the data, the original data can be reconstructed. Since NRZI reconstruction is possible if there is a clock that is four times the bit rate, it can be accomplished if both the sender and receiver both have 48 MHz clocks (the transmission rate is 4 times 12 Mbps).
However, when viewing this from the standpoint of an audio device, the very fact that the sender and receiver both have local clocks becomes a stumbling block.
The Evil of Clocklessness
The fact that there is no clock line within the USB cable leads to a thinner cable which is an advantage. But, no matter how good the crystal oscillators are at the send and receive ends, there will always be some difference between the two. For example, if the sender is sending audio data at a rate of 48.001 MHz and the receiver is receiving at 47.999 MHz, the receiver is reconstructing data slightly slower than the transmission rate. When a large quantity of audio data is sent under these conditions, the buffer will soon overflow, resulting in lost data
On the other hand, if the receiver is running faster, an underflow will occur resulting in a discontinuity in the audio data. In a CD player, angular control can be used to control the motor such that it will synchronize with the playback data rate. But the USB receiver cannot control the sender. The resulting missing data can be digitally compensated (using a smoothing filter, please see Figure 6), but our company's development philosophy does not allow for such deception! (As an aside, there is no problem at all if the data is reconstructed with the receiver's clock after it has all been sent.)
A FIFO is Used to Deal with Packets that are not in Order
USB sends audio data packets on 1 ms intervals. Since, as mentioned previously, pauses in the audio cannot be tolerated, audio playback begins when the first packet arrives, and the next packet must arrive before all of the data in the previous packet has been played. Although we are discussing audio packets in particular, it is possible for the order of packets to be disrupted by other USB packets. In other words, a FIFO large enough to hold at least two packets is required to deal with the possible change of order.
In the case of dealing with 48 kHz, 16-bit stereo data, the buffer capacity must be at least 48 x 16 x 2 x 2 = 3,072 bytes......
USB Clock Error Uses up the FIFO!
On the other hand, the USB specification allows for clock frequency error of 500 ppm. This is an easy-to-accomplish specification for a crystal oscillator and makes the design of the USB circuitry rather easy. However, this is an allowance for an error between the send and receive clocks, and poses a problem for audio.
In this case, the read and write clocks for the FIFO are different. As the 500 ppm error accumulates, the 1 packet buffer margin will be completely used up in 2,000 packets. Since 1 packet is 1 ms, 2,000 packets works out to 2 seconds. If one packet is lost and the device jumps to the next, a popping sound will be heard........
The Terrors of the Isochronous Mode
We still have a problem. It is a problem with a USB mode: in the adaptive isochronous audio transmission mode, the receiver has to determine the bit rate. This means that the bit rate is unknown prior to the time the data arrives.
The bit rate cannot be known prior to actually observing the packet.
Another terror of USB is that, according to the specification, it would not be unusual for the bit rate to change when the operating system is busy. Since the packets arrive on 1 kHz intervals, the PLL must lock within 1ms. In most PLLs, if we say that 1 kHz fluctuations are clearly audible and decrease the gain, we cannot track! Terror of terrors, we have just bumped into a brick wall. Upon doing some investigation, we were actually able to observe fluctuations in the audio frequency characteristics of one company's USB-DAC. Upon listening this could be detected as a disruption in the rhythm of the music. In reality, fluctuations in the time domain will probably result in an unpleasant listening experience. This is probably because they are delaying the lock-up time in order to reduce the jitter distortion.
Also, for isochronous USB data, a buffer is necessary for the time between the beginning of the packet until PLL lock, so the PLL lock-up time is reflected directly in the chip cost. The more audio quality is pursued, the longer the necessary buffer and the longer the time lag when playback begins.
there's a lot more to this article that was intended for people skilled in the art of USB interface, PLL (phase locked-loop) & delta-sigma D/A design. IOW, it's an article written for an analog/mixed-signal engineer. Hence only relevant bits & pieces pertaining to why the USB interface provides a (serious) challenge in hi-end audio data xfer were cut & pasted.
You can read the entire article at your own peril here:
(BTW, there'll be a test afterwards to check comprehension & understanding. LOL! :-D)
Hfisher3380, hope that this helps....
I must admit my eyes are glazing over as I try to read this - too technical for me! What I DO notice is that the article is >10 years old and doesn't deal specifically with the proprietary asynchronous USB technology developed by Gordon Rankin of Wavelength - which appears to address the jitter and clock issues inherent in the technology. No doubt many USB connections are afterthoughts in most CDPs and DACs but the newer generation of specialist asynchronous USB DACs (such as the QB-9 discussed here) appear to have jumped many technological hurdles in truly making the computer a slave to the DAC and the whole system highly jitter-immune.
Here is a more technical explanation if interested:
More importantly, however, my ears tell me that that asynchronous USB technology certainly is capable of state of the art sound.
Hfisher3380, the power supplies are different in the DX5 i believe (bigger) so you may get just an ounce more of the Ayre magic. I've since moved on to other front ends & DAC's as the QB9 while sounding great in other systems I had heard didn't sound great in mine. But those systems where it did sound good, it sounded very nice. I haven't heard a Linn DS but have heard Linn front ends before and they were good but nothing to say OMG about.
LINN CD players are nothing like the DS. LINN was not great at making CD players... they sounded good (when they worked). The LINN Ikemi was a great player for the money, but with these DS units, you would be very surprised at the sound difference between them and almost any CD player. The Akurate DS would simply trash the Ayre USB unit.
Before you all go crazy: I have heard both units and I do not work for LINN or sell LINN.
What I DO notice is that the article is >10 years old and doesn't deal specifically with the proprietary asynchronous USB technology developed by Gordon Rankin of Wavelength - which appears to address the jitter and clock issues inherent in the technology. ....correct, the article is old but I cited it just to show you the inherent flaws in the USB protocol & why Audiofreak32 stated that USB connections are "bad". You might have already know this about the USB standard so if it was a repeat, just ignore that info.
Simplistically, I believe that the TI TAS1020B part that Wavelength, Empirical & Ayre use has the ability to generate 2 clocks. Thus it allows itself to be the master & makes the PC the slave. Thus, jitter can be dramatically reduced using the clean clock on the TAS1020B IC. This was not possible with the other TI USB controller, the 2702. The TI 2702 IC used the data input to extract the clock. Also a bad side-effect of this was the USB controller had to wait for the PC to send the USB packets every 1ms +/- a certain amount to vaariable time. So, there was no exactness to when the data packets would start/stop. Jitter was very high. Thus, Empirical Audio & others (I think Wavelength Audio) simply gave up on this USB controller.
Both the TI 2702 & the TI TAS1020B use an on-board PLL and also FIFO buffers. So, I do not think that this was the technology improvement. I think that it was the dual clock generating ability in the TAS1020B that took the particular USB DACs you are referring to a new level of playback.
Just want to say Linn Klimax has curred my upgratitus. I have been completely satisfied with my system, coming up to 1yr mark now. I feel no desire to upgrade (except for a bigger room and bigger speaker).
I think I would have been just as happy with PD, but the simple appearance of the Klimax and the iDevice interface won me over.
Ayre amp + Linn DS is a damn good combo.