Graham's Blog Archive

Claiming To Be Asynchronous When They Aren’t?

Posted by Graham
October 20th, 2014

Threads about adaptive (isochronous) products claiming to be asynchronous when they aren’t.

The tendency is to suggest Tenor use asynchronous communication only to set-up the drivers, which on older versions are downloads, and on newer versions are on-chip (UART/EPROM) “sub-routines” which cause installed Windows drivers to change the higher sampling rates to whatever the chip can handle (48k???).

If this were to be the case the chip manufacturer (and all who use it) would be cheating as 96k or higher would be being replayed in exactly the same way as something like foobar2000 plays a 96k (or 192) at 48k for an adaptive isochronous device. We have no proof either way.

What we use in the Bitzie and Majestic for USB is plain-honest 48k adaptive isochronous and the DAC section uses oversampling (8x) to give a very similar analogue result without all the faffing about. In the Majestic USB is converted to S/PDIF and reclocked by a Wolfson WM8804 transceiver which sends I2S to a Wolfson WM8741 (highest spec) balanced DAC chip.