hi
F
ace
192
k
H
z
/24bit digital audio interface
REVISION 1.o – NOVEMBER 2010
Copyright © 2010, M2Tech Snc di Manunta & Marino
21
M2Tech
www.m2tech.biz
7. Interface special features
7.1. Output voltage
hiFace has an output voltage which is not compliant with te S/PDIF standard (1.75Vpp
instead of 0,5Vpp on 75 Ohms load). This is a choice made to increase the drive capability
with long digital cables. Please contact your local distributor/dealer in the unlikely event the
output voltage is excessive for your DAC’s input stage.
7.2. Sampling frequency coding in the bitstream
S/PDIF standard requires that some information are encoded in the S/PDIF data stream.
Amongst them, the sampling frequency must be indicated. hiFace doesn’t comply to this
requirement. This feature leads normally to no problem. However, some DAC’s use those
information to display the music’s sampling frequency on the front panel. When using
hiFace with such equipment, the sampling frequency indication always remains on
“48kHz”, even if the DAC is correctly converting 44.1, 96 or 192kHz bitstreams. User
shouldn’t be fooled by this indication and refer to the sampling frequency information
displayed by the player on the computer.
7.3. Output connector choice
hiFace comes in two different versions: with RCA output connector and with 75 Ohms
BNC connector. Which one to choose? It mainly depends on the input connector on your
DAC or A/V receiver. Most units have an RCA input connector, so the RCA hiFace is to be
chosen. On the other hand, some high performance units have both RCA and BNC input
connectors, and some of them only have BNC inputs. The rule is: every time a BNC
connector is available, hiFace BNC should be chosen, as the BNC connection, being it a
true 75 Ohms link, give slightly better performance.
Should a hybrid cable be available (that is, a cable with an RCA plug on one end and a
BNC plug on the other), it is possible to use a hiFace BNC with a DAC provided with an
RCA input, or vice versa. A slight performance increase with respect to an all-RCA link can
be obtained.
