我個人覺得Asynchronous 和 Adaptive 都不能“保證”沒有jitter. Gordon Rankin當然是賣瓜的說瓜甜了.

聽一聽另一家之言
Quote from CEntrance DACport http://www.centrance.com/products/dacport/

Jitter Management - Debunking the Asynchronous Myth

Some manufacturers may lead you to believe that Asynchronous USB transfers are superior to Adaptive USB transfers. This no more true than saying that you "must" hold the fork in your left hand. If you know what you are doing, you will feed yourself with either hand.

The USB argument comes down to jitter management and goes as follows: In Asynchronous mode the device is the clock master. In Adaptive mode, the computer is the clock master. Either way works fine, if correct design principles are followed. Here is the tricky part that often gets omitted: No matter which side is the source of the clock (PC or DAC), the two devices are still connected by the USB cable and the digital data on that USB cable is always irregular because the computer is involved. Computers do many things at once and end up sending data over USB in irregular intervals, no matter who is the clock master on the bus. This irregularity causes jitter. So, there is no jitter-free solution, just like there is no dust-free house. Irregularity always creeps in and needs to be actively managed.

DACport jitter cleanup

Here is where the Asynchronous vs. Adaptive argument breaks down: In either of the two clocking schemes, jitter is present during transmission. It's inevitable and also ok, if it is properly cleaned up prior to the D/A conversion, where it matters most. Neither clocking scheme is superior and both are capable of performing well if you know how to reassemble the bits prior to the DAC. Now, how do you actualy do that? There are many ways, the oldest and simplest of which is buffering. Irregular data comes in, regular data goes out. The most important part is to make sure that samples leaving the buffer on the way to the DAC are clocked accurately. DACport employs JitterGuard™, a proprietary two-stage clock management system that does just that - cleans up the jitter on the USB bus so that samples are virtually jitter-free at the D/A conversion point. The result is a natural response, crisp definition, extra resolution and wide soundstage.

我兩家的東西都沒買（沒預算）.