Group/Foldback Module (GFM-7)1. AUX INPUT connector (XLR type) is balanced, transformer-isolated. The nominal level
and impedance are +4dB and 600 ohms respectively.
2. GROUND (GND) LIFT switch is for pin 1, which is used to avoid ground loops that are
often caused in connection with other equipment and that may induce hum. Sliding th e
ground lift switch from the NORMAL position to the LIFT position cuts ground loops and
may reduce hum. For most applications it should be set to the NORMAL position.
3. ACCESSORY SEND/RECEIVE jacks are unbalanced and their nominal level and
impedance are +4dB and 10k ohms, respectively. They provide the ability to insert signal
processing devices into the signal path for special applications. The regular signal pat h
between the group mixing bus and group out is interrupted at the RCV jack by inserting a
plug into it.
4. SUB INPUT connector (female XLR type) is balanced, transformer-isolated. Its nominal
level and impedance are +4dB and 600 ohms, respectively. This connector is useful for
cascade connection with another mixer to expand the input capacity.
5. GROUND (GND) LIFT switch is for pin 1 of the Sub Input connector.
6. FOLDBACK PEAK level indicator LED turns on when the foldback output signal level
reaches l0dB above nominal.
7. FOLDBACK MASTER control adju sts the output signal level of FB OUT on the rear of the
frame.
8. EQUALIZER for AUX INPUT consists of the following three equalizers
HIGH 10kHz ±15dB boost/cut shelving type
MID 200—5kHz variable ±15dB boost/cut peaking type
LOW l00Hz ±15dB boost/cut shelving type
Flat frequency response is provided at "0" position of each equalizer.
9. EQUALIZER IN/OUT switch permits the equalizer to be either in circuit or out of circuit.
10. GROUP ASSIGN pushbuttons apply the AUX input to any of the four group mixing
busses.
11. AUX INPUT master control adjusts the level of the signal to be fed t o the group mixing
busses.
12. CUE pushbutton assigns the signal (pre AUX INPUT master control) to the cue bus for
monitoring with headphones, monitor speakers, and/or the cue VU meter. A separate cue
VU meter is provided on the RX-7-328, bu t the cue and talkback VU meter is combined
and is switchable on the RX-7-164 and RX-7-248.
13. GROUP ON/OFF pushbutton connects or disconnects the signal to the GROUP out and
group out bus. The adjacent green LED illuminates when the group out is "on".
14. PEAK level indicator turns on when the group output signal level reaches l0dB above
nominal.
15. GROUP FADER TRAVEL is calibrated in dB and insures very smooth operation. The
fader controls the level of the signal to be fed to the group out and group out bus.
16. CUE pushbutton assigns the pre gro up-fader signal to the cue bus for monitoring with
headphones, monitor speakers, and/or the cue VU meter. A separate cue VU meter is
provided on the RX-7-328, b ut the cue and talkback VU meter is combined and is
switchable on the RX-7-164 and RX-7-248.