is ayre qb-9 dac better than cx7e mp?

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:

http://www.usbdacs.com/Concept/Concept.html

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.
FWIW.

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.