SELECTING STEREO, PARALLEL, OR BRIDGE MODE
Each of the four Channel Pairs can be set for normal Stereo operation, Parallel Input mode, or Bridge Mono mode.
Stereo Mode- Each channel within the pair remains independent, and may be used for two different signals.
Parallel Mode - This setting connects both inputs of a pair together. One signal feeds both channels. Each channel's Gain control and speaker connection remain independent.
Bridge Mode- This setting combines both channels of a pair into a single channel with twice the output voltage. Use only the first chan- nel's input and Gain control. Set the second channel's Gain control at minimum. The load must be rated for 140V, and is connected as shown on page 6.
Stereo Mode - Switches 4, 5, 6 and 7 are all set to the DOWN position.
Parallel Mode - Switches 4, 5, and 6 are set to the UP position. Switch 7 is set to the DOWN position.
Bridge Mode- Switches 4, 5, 6 and 7 are all set to the UP posi- tion.
EN
Do not connect different inputs to each side of a channel pair when operating in parallel or bridge mode.
SETTING LOW FREQUENCY FILTERS
Each channel has a 12dB per octave Low Frequency filter to prevent saturation of the 70V speaker transformers. This reduces distortion and prevents amplifier overload.
The filter should only be turned off for driving subwoofers with special low frequency transformers. The 50 Hz set- ting usually works well with high quality speaker trans- formers. The 75 Hz setting works well with
Each channel has its own switches for LF filter on/off and frequency selection.
The first channel uses switches 2,3. The second channel uses switches 8,9. Switches 3 and 8 turn the LF filter ON. Switches 2 and 9 select 50Hz or 75 Hz
TERMINAL BLOCK INPUTS
Each channel has a balanced
The input impedance is 12k ohm balanced or 6k ohm unbalanced.
Balanced connections are recommended for less AC hum and interference, especially with long cable runs. Unbal- anced connections may be suitable for short cables. The signal's source impedance should be less than 600 ohms. If the DataPort is being used, do not connect cables to the terminal blocks.
Balanced inputs: Strip the wire ¼ inch (6 mm) and connect to the plug as shown. Be sure to tighten the screws firmly.
Unbalanced inputs: Strip the wire ¼ inch and connect to the plug as shown. The middle pin must be connected to the
shield pin as shown. Be sure to tighten the screws firmly.
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