Theater-Solutions VCS User Manual
VCS
VCD
Impedance Matching
Stereo Volume Control
Models VCD, VCS
The impedance matching volume control is a full range volume control that can be adjusted to meet the
requirements of your installation. With a simple change to the placement of two shorting bars on the printed
circuit board, you can safely connect multiple pairs of speakers to a
the charts provided in this manual to determine how to set the shorting bars to ensure the proper impedance
level is sent to your amplifier.
Features and Technical Information:
• Can be used with any combination of 4 ohm, 8 ohm, or 16 ohm speakers
• Impedance is adjusted by positioning two shorting bars to the appropriate terminals
• 12 steps of attenuation: first position is “off”, steps 2 through 7 at 3db each, steps 8 through 11 at 6db
each, and final position allows the signal from t
he amplifier to pass through completely.
• Frequency response: 35 Hz to 20kHz (+0/-2db) at rated power
• Input and Output connections accept up to 14 gauge speaker cable
• Independent grounds for use with any amplifier
• Decora-style faceplate included
• Fits most deep single gang electrical junction boxes
Installation Considerations
Type of Speaker Cable
For most applications, we recommend you use 14 or 16 gauge, oxygen free copper (OFC) speaker cable for
the volume control connections. For individual lengths greater than 80 feet, 14 gauge cable is
recommended. When running speaker cables inside walls, you must use a special type of speaker cable.
For most building codes, the requirement is that the cable has a specific “CL” rating, such as “CL2” or
“CL3”.
Avoiding Interference
Speaker cable can act as an antenna for electrical noise. Locating the speaker cable too close to a light
dimmer or switch may cause a “buzzing” or “popping” sound to be heard through the speakers. If you must
locate the volume control wiring near electrical devices, try to route the speaker cables a minimum of 18”
away form the electrical wiring and cross any electrical wiring at 90 degrees.
:
single amplifier (or receiver). Refer to
x1, x2, x4, x8 = Positions for the Shorting Bars
If you are using a 2 ohm rated amplifier:
4 ohm speakers
8 ohm speakers
16 ohm speakers
If you are using a 4 ohm rated amplifier:
4 ohm speakers
8 ohm speakers
16 ohm speakers
If you are using an 8 ohm rated amplifier:
4 ohm speakers
8 ohm speakers
16 ohm speakers
x1 x2 x4 x8
2 pairs 4 pairs 8 pairs 16 pairs
x1 x2 x4 x8
4 pairs 8 pairs 16 pairs 32 pairs
x1 x2 x4 x8
8 pairs 16 pairs 32 pairs 64 pairs
x1 x2 x4 x8
1 pairs 2 pairs 4 pairs 8 pairs
x1 x2 x4 x8
2 pairs 4 pairs 8 pairs 16 pairs
x1 x2 x4 x8
4 pairs 8 pairs 16 pairs 32 pairs
x1 x2 x4 x8
---- 1 pairs 2 pairs 4 pairs
x1 x2 x4 x8
1 pairs 2 pairs 4 pairs 8 pairs
x1 x2 x4 x8
2 pairs 4 pairs 8 pairs 16 pairs
X1X2X4
X8
X1X2X4
X8
* Shorting bars
Installation
1. Select a convenient mounting location for the volume control.
2. Run 4-conductor speaker cable from the amplifier (positive and
negative for both the left and right channel) to the volume control.
Similarly, run 2-conductor speaker cable from each of the first
pair of speakers to the volume control. Label the cables for future reference.
3. Connect the speaker cable to the volume
a. Strip 1/4” of insulation from the end of each cable
b. Tightly twist the wires in each cable until there are no frayed ends
c. Insert the 4-conductor speaker cable from the amplifier into the
input terminals
d. Insert the two 2-conductor speaker cables from the first pair of speakers
into the output terminals
4. Connect additional speakers in parallel.
5. Make certain that all connecti
ons between your amplifier and the volume control, and between the
volume control and each speaker, are “phase correct”, that is + to + and – to –.
6. Turn the volume knob to the “off” position (all the way counterclockwise), turn on the amplifier, and test
the functionality of the volume control.
control:
Impedance Correction
This process ensures that the impedance load shown to the amplifier (or receiver) never goes below the rated
capabilities of the amplifier. See the charts (opposite page) for specific impedance loads that will be
presented to your amplifier, depending on the quantity and impedance of the speakers you are using. Most
amplifiers are rated at 8 ohms (stable down to 4 ohms).
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