Aphex 188 Eight Channel Mic Preamp User Manual
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188
Ground loops hardly ever cause problems within the 188 since it was designed with high
immunity. However, other equipment connected to the 188 may experience hum and noise from
a ground loop. Ground loops can occur when various interconnected equipment is powered from
separate AC circuits that are fed from opposite phases of the power feeder. Most service panels
assign odd numbered breakers to one phase and even to the other. Rooms that are powered from
more than one circuit can have outlets that are out of phase. Adjacent rooms may be powered
with opposite phase.
NOTE: If your system is plagued with ground loop troubles, you should try to get all the
equipment onto the same phase or use a local power isolation transformer.
3.5 MICROPHONE INPUT
The eight transformer coupled microphone INPUT CONNECTORS are locking female 3-pin
XLR’s wired with pin 2 positive.
3.6 OUTPUT CONNECTOR
DB-25 using the TASCAM standard for the eight transformerless impedance balanced
outputs .
DB-25 PIN CONFIGURATION (Analog OUTPUT)
The following chart is a pin configuration for the analog DB-25 connector
.
This connector pinout matches the Tascam Analog DB-25 connector that has also been adopted
by many other manufacturers such as Mackie and Yamaha. Ready made cables can be purchased
to connect with other products, or to obtain a break-out to XLR plugs.
2 Positive (+)
3 Negative (-)
1 Shield (Ground)
CH1
CH2
CH3
CH4
CH5
CH6
CH7
CH8
(+)
24
10
21
7
18
4
15
1
(-)
12
23
9
20
6
17
3
14
GND
25
11
22
8
19
5
16
2
Female
Male
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Aphex Model 188