C1.2 User Manual
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7.4 C1.2 with D1.5/D1 (both with SYNC-I/O board) and T1 Time Reference (or
other 10MHz external master clock)
When both the D1.5/D1 and the C1.2 are equipped with a SYNC-I/O board, and an ultra-high stability clock
generator such as the CH Precision T1 10MHz Time Reference is available, optimum performance is obtained
when both the D1.5/D1 and C1.2 lock themselves to the external clock generator. Direct clock connections from
the T1 to the individual devices are preferred over daisy-chaining. The audio stream goes from the D1.5/D1 to
the C1.2, and the clock signal is distributed to both the D1.5/D1 and C1.2 from the T1. The schematic below shows
how to connect such a system:
D1.5 clock source: SYNCHRO BNC 75
Ω
C1.2 clock source (for this input): SYNCHRO BNC 75
Ω
If in this configuration the C1.2 is unable to lock (open padlock) on an incoming S/PDIF audio stream but properly
detects its sampling frequency (a valid Fs is displayed instead of “Fs UNKNOWN” in the upper left corner of its
display), it probably means that the S/PDIF source does not comply with AES standards and/or has too much jitter.
To overcome this problem, set the clock source as Sample Rate Convertor (SRC) – Sync 75
Ω
for this input.
D1.5 – C1.2 – T1 connection when SYNC-I/O equipped
Ground
link
Ground
link
AC
power
AC
power
CH LINK HD
D1.5
C1.2
X1 umbilical cables
BNC clock cables
AC power
AC power
T1
X1
