Gallien-Krueger 8000RB User manual

Service Manual
800RB

Table of Contents
Operating Instructions 3
Turn On / Calibration Procedure
Schematics 11
Engineering Change Orders (ECOs) 24
Bill of Materials 34

800RB T/O Procedure
GK Doc. # 420-0045-C
Board #’s: 206-0045-C (preamp), 206-0044-A (power amp),
206-0048-A (power supply). 800RB- all options 8/19/91
Setup
1) Variac on 0, power switch off- connect power cord.
2) Connect outputs to load box (100W-> load A, 300W-> load B).
3) Resistance loads open (switch in center).
4) Speaker on (connected to 100W output).
5) Load box to scope-B and AC- VM.
6) Set scope switch on load box to look at load A (down).
7) Set oscillator on 200 Hz sine wave @ 5mVrms (-46dBV).
8) DVM on 20mV (dc) range.
9) Scope –B on 10V/cm.
10) Scope sweep on 1ms/cm, scope trigger on B on RB front panel, set:
11) Tones, masters and boost to 10, switches out.
12) Volume and bi-amp frequency on 0.
Power Supply and Power Amp Test
NOTE: Unless otherwise specified, output levels are in Vrms and taken from 100W output. Flip scope switch up to
load B to see 300W output.
1) Power switch to ON. Gradually turn up variac to 50V, while listening to speaker and watching scope and
ammeter. Output should go negative, then snap back to 0V. Flip switch to check 300W output, also.
2) Check regulated supplies: (+or-) 14.5V, (+ or -) 1V.
3) Adjust variac to 120V and turn speaker OFF.
4) Set bias: 300W- adjust R38 (on ’44 board) for 5mV DC across R48, R49,& R50 (most pos. of the 3) and R54,
R55, & R56 (most neg. of the 3).
5) Set bias: 100W- adjust R14 for( on ’44 board) for 5mV across R25, R26.
6) Power LED and boost LED should be lit.
7) Connect oscillator to input. ( 200 Hz @ -46dBV).
8) Turn on 4 ohm load for 300W amp and 8 ohm load for 100W amp.
9) Adjust volume for slight clipping in 300W amp. 300W output- 36Vrms.
10) Reduce volume for slight clipping in 100W amp. 100W output- 28Vrms.
11) Engage –10dB switch- output becomes 6.0V. Disengage switch.
12) Turn boost to 0. Output becomes 3.1V.
13) Turn master to 0. Output becomes 0V.
14) Turn loads off.
Tones, Filters, and Bi-Amp Test
1) Set bi-amp knob to 0, all others to center (12 o’clock), switches out.
2) Set scope-B to 5V/cm and 1ms/cm.
3) Set oscillator to 200Hz square wave at –46dBV.
4) Look at output, compare to Figure 1.
5) One at a time, turn tone control knobs and compare output to figures (resetting each to center position after
finishing):
A) Treble to 10- Fig.2; treble to 0- Fig.3.
B) Hi-mid to 10-Fig.4; hi-mid to 0-Fig.5.
C) Lo-mid to 10-Fig.6; lo-mid to 0-Fig.7.
D) Bass to 10-Fig.8 bass to 0-Fig.9.
6) Engage Low-cut switch, compare to Fig. 10. (Disengage).
7) Engage Contour switch, compare to Fig. 11. (Disengage).

8) Engage Hi-boost switch, compare to Fig. 12. (Disengage).
9) Engage Bi-amp switch. Compare 100W output to Fig. 13.
10) Compare 300W output to Fig. 14.
11) Set Freq. Knob 10, compare 100W output to Fig. 15.
12) Compare 300W output to Fig. 16. Disengage Bi-amp switch.
Noise Test
1) Remove oscillator input.
2) Turn front panel knobs to 10, switches out.
3) Connect speaker to 100W output and listen for noise. It should be smooth and not crackling. Repeat for 300W
output.
4) Change AC voltmeter range to 1V
5) Noise( both amplifier outputs) should measure less than 400mV.
6) Engage low-cut, contour, and hi-boost. Noise<400mVrms.
7) Volume to 0. Noise< 110mVrms.
8) Boost to 0. Noise<15mVrms.
9) Engage bi-amp switch. 100W noise< 20mVrms, 300W noise< 5mVrms.
RETURN KNOBS TO ZERO, SWITCHES OUT- READY FOR BURN-IN.

800RB T/O Procedures Rev.1- 2/1/88
1) Inspect wiring on PC boards.
2) Connect power:
A) Variac at zero.
B) Speaker on B ,scope on B.
C) Load off.
D) Trimpots halfway.
E) Tones and master on 10, filters out, volume off.
3) Gradually adjust variac to 50 Vrms. Listening to speaker and watching scope signal should pop negative then go
to zero.
4) Check regulated supplies: (+or-) 14.5 V.
5) Adjust variac to 120V and turn speaker off.
6) Set bias:
A) Adjust 38R TP to get 5mV across R48, R49, & R50 (the most pos. of the 3), and R54, R55, &R56 (the most
neg. of the 3).
B) Adjust R14 to get 5mV across R25 & R26.
7) Connect sine input ( 200Hz, 20 mVp-p) – 44dB.
8) 8 ohm load for 100W amp, 4 ohm load for 300W amp.
9) Check for full power on high and low amps.
A) Slowly turn up volume until amp hits the rails- check output on both amps: 100W= 32 Vrms, 300W=
40Vrms.
B) Check master pots when looking at output of both amps.
10) Turn loads off.
11) Connect square wave input ( 200 Hz, 20 mVp-p) –44dB.
A) Boost on zero, volume at 2 o’clock.
B) Test attenuation and filters.
C) Test tone control.
D) Turn on bi- amp- check if crossover works on both high and low amps.
NOTE: When test filters, tones and crossover compare w/ figures.
12) Turn bi-amp off.
13) Check direct out- NOTE: If direct out does not seem right- use DVM should read .6Vrms at full power (AC)
14) Remove input, speaker on, no load.
15) Noise and tap test:
A) <300mV- all controls on 10, contour off.
B) <500mV- all controls on 10, contour on.
C) <700mV- all controls on 10, contour on, crossover on.
D) <70mV - volume off, controls on 10, contour on.
E) <40mV - volume off, controls on 10, contour off.
F) <6mV - volume off, controls on 10, boost off, contour off.
NOTE: <30mV- volume off, controls on zero, bi- amp highmaster on 10. This is to be done while listening to high end
of the amplifier.