AD11
Operation
11
The Sample Frequencies (SF) setting controls the digital audio and Word Clock outputs of the AD11.
When operating on external clock, it is also necessary to set the SF of the AD11 to match the SF of
the external clock source.
- To change the desired SF, enter the Setting mode by clicking the
switch once, and then click it
either up or down to move the cursor to the position above the legend for the desired SF.
- With the cursor above the desired SF legend, click the right SELECT switch down in the
set
direction once to change the output SF. Without moving the cursor, clicking the
set
switch again
will
have no effect
because one SF must be selected at all times
- wc & dig-a (for External Clock Operation)
These two settings are used to synchronized the AD11 to an external Word Clock (
wc
) or AES/SPDIF
clock source (
dig-a
for
“digital audio signal”). The status indicators are numbered 5 & 6 in Diagram 2.
The external clock signal (Word Clock or AES/SPDIF clock
) must be connected to the “
clock in
” BNC
connector on the rear panel of the AD11 and the SF of the external clock must match the SF setting
of the AD11 for the proper operation. As a safety precaution, in External Clock operation a miss-
match in SF will cause the AD11 digital output to “mute” and the front panel meters to indicate “no
output
signal” in Operating mode.
- In addition to the status indicators that show whether an external clock function is enabled, there are
“LOCK” indicators for each format of external clock. They are located in the “
left
” (upper) row,
immediately above each status indicator:
- Word Clock
“LOCK” is labeled “a” in Diagram 2
-
AES/SPDIF “LOCK” is labeled “b” in Diagram 2
When the AD11 is set to the Sample Frequency of the incoming external clock signal and it can
successfully lock to the external clock signal, the LOCK indicator illuminates. If the LOCK indicator
does not illuminate, check the SF settings of the AD11 and external clock source, the external clock
settings (either the
wc
or
dig-a
LED
must also be illuminated
), and cabling for possible problems.
-
If the AD11 is not “locked” to the incoming external clock, it does not operate properly; even when
one of the external clock settings is selected (
wc
or
dig-a
is “On” with no “Lock” indication). Operating
the AD11 in this manner can result in recordings with “clicks,” “pops” or “drop-outs” recorded along
with the music program, or at the incorrect sample rate.
- Al
though the AD11 will “lock” to an SPDIF sync source, it is recommended that AES sync is used if
possible because the low voltage of the SPDIF signal makes it less reliable for synchronization.
- aes & spdif (Output Format)
The
“SPDIF” digital audio format is now the IEC 60958 type II Consumer format. For simplicity, the
“SPDIF” designation will be used both in this manual and on the front and rear panels of the AD11.
- To change the Output Format, enter Setting mode by clicking the
switch once, and then click it
either up or down to move the cursor to the position above the legend for the desired Output Format.
- With the cursor above the desired Output Format legend, click the right SELECT switch down once
in the
set
direction to change the Output Format. Clicking the
set
switch again will have
no effect
because one Output Format must be selected at all times.
In addition to the digital audio and “embedded clock,” the digital code contained in the AES and
SPDIF data streams contain other “informational bits” or “flags.” The digital audio code and clock
signal are the same in both formats; but the informational bits are quite different.
As a result of these similarities and differences, most digital audio equipment can accept either input
format using simple adapters or adapter cables. The informational bits are either ignored, generate
only status warnings if a miss-match occurs, or in some cases require a manual setting change to
allow “normal” operation when a miss-match occurs.
