VC220pm
Digital Volume Control
Installation Instructions
Warning: To be installed and/or used in accordance with appropriate electrical
codes and regulations.
Caution: Do not install these keypads in an electrical junction box with 110V or
higher unless an approved barrier separates the high and low voltage sections.
Description: The Knöll VC220pm digital volume control attenuates stereo speaker
signals in 17 steps. It contains Powermatch circuitry allowing connection of up to eight
VC220pms to a receiver. A non Powermatch version, model VC220 is available. The
VC220pm includes mute and start-up functions. The VC220pm is controlled with a
VC200 or VC201 keypad or an external controller such as the VCI-28 interface. Up to
three keypads can be connected (daisy chained) to a VC220pm. The VC200i and VC201i
keypads contain an internal infrared receiver (no extra wiring is necessary) to control the
stereo and other systems. The VC220pm requires a 12VDC power supply, is usually
wall-mounted and works best if mounted vertically.
Basic System Layout and Pre-Wiring: See “Typical Wiring Diagram” on the back
page. The VC220pm makes a noticeable “click” sound when changing volumes. We
suggest mounting it in a low voltage panel, electrical room, closet, etc. From one to eight
VC220pm’s can be connected to a single amp or receiver (that has 4 ohm capability).
VC200’s and VC201’s cannot be attached to the same VC220pm. Only one VC200i or
VC201i can be connected to a single VC220pm.
Use the standard T568A wiring practices to run a cat 5 or cat 3 wire from the keypad or
controller to the VC220pm. If more than one keypad controls a single VC220pm daisy
chain the wire from keypad to keypad. If the VC220pm(s) are not located next to the
stereo, run a single eight-conductor cat 3 or cat 5 wire run from the stereo to the
VC220pm(s) for the power supply, the infrared system and future upgrades such as
paging override.
From each VC220pm run a fire rated two-conductor speaker wire to each speaker. To
save time and money, most installers run a four-conductor speaker wire from the
VC220pm to the closest appropriate speaker and then run a short two-conductor speaker
wire to the other speaker. If there is more than one pair of speakers connected to a single
VC220pm, the speakers can be wired in series or parallel whichever makes the
impedance closest to 4 or 8 ohms. Do not attempt to make the final combined speaker
impedance less than 4 ohms.
If the VC220pm(s) are not
located next to the stereo, run a single fire rated four-
conductor (or two two-conductor) 14-18 gauge speaker wire from the stereo to the
VC220pm(s).
Connecting VC200/VC201 keypads to VC220pm controllers:
Use a single cat5 wire using all eight conductors (usually run inside a wall). Always use
standard T568A Cat 5 wiring practices (shown below). Use the correct wire pairs.
Polarity is VERY important! The stereo signal is not routed to the keypad, just the digital
control signals. Signals from an infrared receiver (if used) are routed down the same Cat
5 wire. If more than one keypad is to be connected to a VC220pm controller, the wires to
the keypads are paralleled.
VC201i keypads are connected
to VC220pm controllers, the
same as other keypads, the
only difference is extra power
supply and IR emitter wiring
are required (see Infrared
connection diagram below).
Connection to Stereo Equipment: Remove the VC220pm eight-position speaker
connector. The stereo amplifier or receiver outputs (left and right) are connected to the
VC220pm connector labeled “TO AMP”. Be very careful to observe the correct polarity.
The VC220pm uses independent floating grounds so bridged amplifiers can be used
safely.
***The VC220pm is rated for use with maximum
120 watt per channel amplifiers. DO NOT use
higher-powered amplifiers with this product
for safety reasons.***
Up to eight VC220pm controllers can be connected to a single amplifier or receiver if it
rated for 4-ohm use. If the amplifier or receiver is rated for 8-ohm use, up to three
VC220pm controllers can be connected. Wire from the amplifier speaker terminals are
always wired in parallel to the VC220pm controllers “TO AMP” terminals either by
stripping and soldering, using a speaker wire paralleling board (our model WT6), or daisy
chaining from one VC220pm connector to the next VC220pm connector etc. Connect all
VC220pm’s to amplifier speaker A or speaker B terminals, but not both. Wire the
VC220pm connectors labeled “SPEAKER” directly to the correct speakers, again strictly
observing polarity.
Power Requirements: The VC220pm
needs a 12vdc power supply. The
VC220pm controller also supplies
power to the keypads. A maximum of
60mA is needed for each VC220pm. If
possible, connect the 12vdc power
supply to the switched outlet on the
rear of the amplifier or receiver. This
wiring causes the VC220pm to reset to
brown 8
white/brown 7
orange 6
white/blue 5
blue 4
white/orange 3
green 2
white/green 1
Stereo
12VDC power supply plugged
into stereo switched outlet
POWER
INFRARED
+12V G 12V SIG
Infrared
emitter(s)
12VDC power supply
plugged into power
full time
+
-
+
-
VC220/VC220pm