| Wheatstone
General Installation FAQ |
| Question
|
Answer
|
|
| What
type of wire do you recommend for analog and digital audio? |
Any modern installation will benefit by
using digital audio wire
exclusively for all analog and digital connections. Cable designed for
digital audio has low capacitance, tight twist tolerances, and provides
superior performance compared to analog cable. |
|
| What
gauge of wire should I use with my D-sub 25 connectors? |
The factory supplied crimp style AMP DB-25
mating connectors (Amp part
number 1-745496-8)
are designed for 26 to 22 AWG wire. |
|
| What
kind of punch blocks should I use for my digital audio
installation? |
We recommend Krone 50 pair termination
blocks – model
6652-1-880-10.
Be
sure to wire the blocks in a pattern of Pair 1 H-L-SH, Pair 2 SH-H-L,
Pair 3
H-L-SH, etc., to take advantage of the built in patch and test
point cables manufactured by Krone. |
|
| How
do I wire an unbalanced analog output to a balanced analog input? |
Wire the unbalanced Hi to the balanced Hi,
unbalanced Shield to the
balanced side Lo and Shield. |
|
| How
do I connect an unbalanced DIGITAL (SPDIF) CD output to a balanced
AES input? |
We suggest using a "balun" or format
converter if possible, but if
not available you can try connecting the CD (+) to AES in HI (+),
connect CD (-) to AES in LO(-). Leave the AES input’s Shield
connected at the console/card end only. This works because all of our
AES inputs are transformer coupled. The impedance is not correctly
matched, but this method will work in a pinch. The AES receiver will
ignore the copy protect (SCMS) bit. |
|
| How
do I connect a balanced AES digital console output to an unbalanced
(SPDIF) input? |
You must use an external AES to SPDIF
converter. |
|
| Do
I need to use a telephone hybrid with the phone module? |
Yes. Phone modules are designed to
interface via balanced analog
line level connections to an external telephone hybrid. They are
NOT
intended to interface directly with the phone line. Doing so can
result
in damage to the console. |
|
| Where
can I find phone module application information? |
Please see our white paper Making
The Connection (pdf). |
|
| How
do I use the channel ON tallies from my three mic channels to
make my ON Air light come on whenever any of three mics are on? |
To do it this way with some consoles you
need to add diodes in what
is commonly called a wired-OR configuration. The orientation of the
diodes will depend on the polarity of components and/or voltages in the
external circuitry. But this is generally not necessary. On most of our
consoles you can set the CR mute function for the desired mic channels
and then wire your ON AIR light to the console’s ON AIR TALLY
output,
following the console-specific instructions as outlined in the
console’s manual. |
|
| What
is the logic output port topology? Open collector? Relay contact? |
Actually, neither. Almost all logic port
outputs use a solid state
switch, LH1522 or equivalent. This solid state
switch works like a contact closure with
about 10 ohms of resistance. It is also bi-directional, but we
recommend
that you wire ground side signals to the (–) terminals to keep
the documentation and wired polarity consistent. You can switch a
positive or negative voltage but be aware of the potential for dropping
too much voltage across the 10 ohm resistance of the solid state switch
and limit current to less than 100mA. |
|
| What
is the logic input port topology? |
All logic input ports are the photo diode
side of a solid state
switch. Logic inputs have a built in current limiting resistor that
allows them to be controlled from +5 to +12vDC. Connect the external
voltage to the (+) terminal and externally switch the ground side to
activate the input. |
|
| Do
I need to use an external DC power supply when wiring logic
connections? |
In most cases the answer is yes. Logic
circuits are opto-isolated
for maximum protection. Certain products, like the Wheatnet IP SAT and
the
Micro-Sat, do supply +5v and Ground. |
|
| What
kind of “wall-wart” should I use to provide power to
the logic inputs? |
You can use an external
“wall-wart” type DC power
supply in the +5 to 12VDC range. Select a current rating based on the
number of switches and LED’s (allow 10-15mA each). In most cases
it makes sense to jumper the positive (+) side of the supply to all of
the logic Input pins right at a punch block. Then externally switch the
ground side of the “wall-wart” to the negative (-) logic
Input port to activate it. Same with logic outputs, switch the GND side
of the external supply. You can switch a positive or negative voltage
but be aware of the potential for dropping too much voltage across the
10 ohm resistance of the solid state switch and limit current to less
than 100mA. |
|
| What
size UPS should I buy for my console? |
See the suggested UPS rating for your
Wheatstone product as shown in the table
below. Note that these
ratings are based on the maximum configuration for the product. Your
product may be short loaded or draw less power than shown in the table.
| A-20/A-32 |
200W |
| A-300 |
500W |
| A-500 |
500W |
| A-5000 |
500W |
| A-6000/7000 |
500W |
| D-500 |
500W |
| D-600 |
500W |
| D-700 |
500W |
| D-4000 |
500W |
| D-5000 |
500W |
| SP-8 |
500W |
| TV-600 |
1200W |
| TV-80,
TV-1000 |
| console |
2000W |
| SS Cage |
300W each |
| RC-1000 |
100W |
|
|
|
|
