Operating Notes
Generally, operating the GQ600 is very straight forward, however certain functions may not
be immediately obvious and these are discussed here.
Low Pass Filter. 18dB/octave filters are provided for each channel to provide additional
H.F. driver protection against unwanted high frequency signals. These have negligible effect
on frequency response at 20kHz. All units are factory set with these filters in, if not required
these filters can be removed from the signal path by changing the position of two jumper
links on the main circuit board, see following diagram.
Output Balancing Transformers. Outputs are fully electronically balanced as standard. If
optional output transformers are required proceed as follows:-
1.Remove four "jumpers" from CN4 and CN8 on main circuit board (located near XLR
outputs).
2.Fasten two output transformers type 7470 to the inside of the rear panel chassis, using
the screws and washers provided, through the two mounting holes located above each
Klippon connector. Plug in transformer connectors into CN4 and CN8.
3.Monitor output noise of unit and rotate appropriate transformer until noise (hum) is at a
minimum. Fasten transformer in this position and repeat for other channel.
Input Balancing Transformers. Inputs are fully electronically balanced as standard. Input
transformers if required, should be requested at time of purchase if possible. if it necessary
to fit input transformers to existing units proceed as follows:-
On main circuit board.
1.Remove R2, R3, R4, R6, R8, R11, R15, R16, R17, R19, R21, R24.
2.Fit R2 and R15 = 10k ohms, R11 and R24 = 0R0 link.
3.Solder in input transformers type LL1540 to positions TX2 and TX3 on main circuit
board.
Grounding. The Screen (shield ) pins on all audio connectors are normally connected
directly to the ground pin of the IEC mains inlet. The chassis is also directly connected to
this pin. Never operate this unit without the mains safety ground connected. Signal ground
(0V) is in turn connected to the chassis ground via a 10R resistor.
GQ600 Page 8
