DACS Ltd, Unit A19 Stonehills, Shields Road, Gateshead, NE10 0HW
2
Using the DACS
HeadLine
Guitar Switching System
User Interface/Selector Unit
The
HeadLine
selector unit has 12 illuminated buttons, 8 red and 4 blue. The red buttons are for
selecting guitar amplifiers and the blue for selecting loudspeaker cabinets. The loudspeaker
connections are continuously monitored. This ensures that there is a functioning loudspeaker
present and there is no short or open circuit.
When routing, available speaker outputs will be shown by a dimly lit switch. Unavailable outputs will
not be illuminated.
NOTE – when initially powered up with NO SPEAKERS CONNECTED all 4 blue switches will
flash.
To label each amplifier and cabinet we use a Neodymium magnetic strip set into the case, onto
which white magnetic labels are placed (we supply pre-cut strips with a whiteboard pen in a
drawstring bag). The strips are cut to size. We have supplied extra labels, so you can keep a
collection of prewritten labels or printed tape labels ready for use on a new session.
Relay Switcher Unit
The
HeadLine
switcher unit switches all screens/0V lines with the signal lines ensuring total isolation
between amplifiers, and total fidelity of transmission.
On unselected amplifier inputs, the signal and screen are linked (like a ‘silent switch’ jack) to ensure
there is no hum or other interference picked up by the amplifier. Unselected amplifier outputs are
connected to a dummy load to ensure that sensitive valve output stages are not compromised.
When a new amplifier or loudspeaker is selected, the first step is to disconnect the currently active
amplifier input line and link the signal and screen. Very shortly after this the selected amplifier
output is routed to the selected loudspeaker, then the guitar input is connected.
The very short delay gives the amplifier a chance to settle, and any reverb to dissipate before
disconnecting its output. Changing loudspeakers follows the same procedure.