207d
instruction Manual
Aphex Systems Ltd. Model 207D
Page 10
207d
2-ch tube mic preamp with adc
Page 11
Aphex Systems Ltd. Model 207D
Installation & Interfacing
may both be used at the same time to feed separate
equipment. Both jacks run at the same output level
but are not fully isolated from each other. Shorting
out the XLR will take down the 1/4 phone. However,
shorting the 1/4 phone will not affect the XLR. You
may safely plug a mono style (TS) 1/4” phone plug
into the phone jack and take an unbalanced output.
The diagram shown below explains the electrical rela-
tionship of the two output jacks.
If you intend to take an unbalanced output from
the XLR jack, you must not ground either pin 2
or 3. Simply take from pin 2 and use pin 1 for
ground. Leave pin 3 unconnected.
Refer to Appendix C & D for more information on the
proper wiring of balanced and unbalanced lines.
3.8 OPERATING LEVEL SWITCH
Between the input and output jack is located the
Operating Level switch. This sets the nominal oper-
ating level for both output jacks simultaneously to
either -10dBV or +4dBu. You should select the posi-
tion that most closely matches your receiving equip-
ment. In the event that you are not familiar with the
operating levels of the equipment in your system, you
should consult your manuals. In general, most entry
R
Tip -SEND
Ring - RETURN
Sleeve - GND
TABLE 3-1 - INSERT “Y” CABLE PINOUTS
level “home studio” equipment operates at -10dBV
as it is assumed that the user will likely intermix home
hi-fi equipment, such as cassette decks and CD play-
ers. Most professional recording gear and live sound
equipment operates at +4dBu.
3.9 OUTPUT TRIM
In addition to the OPERATING LEVEL switch on the
back panel, there is a front panel trim for precise
output level matching. The OUTPUT TRIM is recessed
to stay out of your way and can be adjusted with a
small screwdriver blade. The range of adjustment is
0 to -12dB. First, set the OPERATING LEVEL switch to
the appropriate position. Next, using a loud input or
an oscillator, drive the OUTPUT HEADROOM meter to
ZERO. Set the OUTPUT TRIM to just barely drive your
equipment to its maximum input level. If you are in
doubt about how to do this, simply set the OUTPUT
TRIM fully clockwise and rely on the OPERATING
LEVEL switch to get you close enough.
3.10 WORD CLOCK IN (BNC Jack)
If you use a house or master clock source, then con-
nect it here. The input impedance is 75 ohms. You
should then be sure the sync mode is set to EXT on
the front panel. If you don’t seem to get any S/PDIF
output, then you should double check if external
clock is present.
3.11 DIGITAL OUTPUTS (AES3 and S/PDIF)
Both outputs can be used at the same time. Signal
will be present if the 207D is set to any internal clock
frequency or is externally clocked by a valid word
clock source from 32 to 96kHz. The outputs are
muted if there is no valid clock.
OUTPUT JACK SCHEMATIC
with OPERATING LEVEL SWITCH
604
Ω
2 (+
)
3 (-)
1
Tip
Ring
Sleeve
+4dBu
-10dBV
OUTPUT PAD
1/4” PHONE JACK
XLR JACK
604
Ω
715
Ω
267
Ω
56
Ω
56
Ω