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Introduction
Mitchell & Johnsons USB board allows for state of the art connection via USB.
For correct operation of the USB interface with Microsoft Windows machines, a USB driver
must be downloaded, installed and configured. Please see page 35 for instructions.
Apple OSX® and Linux® operating systems do not require an additional driver.
They will however require their respective audio playback devices to be set to”XMOS”as
the default.
Asynchronous USB
In a conventional USB playback scenario, the computer varies the speed of the digital au-
dio stream emanating from it’s USB port, itself. The DAC has no option but to slavishly
follow this variable data rate. This is not a suitable method for producing high quality audio
since it results in high jitter which in turn results in high distortion.
Asynchronous USB playback requires the DAC to accurately regulate the data output
speed of the computer to practically eliminate jitter based distortion.
In practice this is a very complex task and requires the computer to have a free USB 2.0
port, connected to the DAC via a suitable high speed USB 2.0 cable.
Mitchell & Johnsons 800 series pre-amp uses a USB high speed device which upon con-
nection, invokes the USB port’s high speed mode. This mode is only available under USB
2.0.
Windows does not natively support High data rate audio formats, hence the need for a driv-
er to be installed.
UPDATE
…..Windows 10 creators update now includes the XMOS driver as standard.
