Page 1
23. CIRCUITBREAKER:The B4R employs an AC line
circuit breaker to help protect against damage due to excessive current demands. If the amplifier stops work-
ing, check the circuit breaker. If it has opened, the but -
ton will be protruding and showing a contrasting color .
Y ou can reset the circuit breaker by pushing it in until it
latches. The breaker must cool down for a short time before the button will latch. If the circuit breaker opens
repeatedly, have the amplifier checked by a qualified service person.
24. ACLINE IN: Firmly insert the supplied AC power
cord into this socket until it is fully seated. Plug the male
end of the cord into a grounded ACoutlet. DO NOT
DEFEAT THE GROUND PRONG OF THE AC PLUG!
25. SPEAKER OUTPUTS: The 1/4 jacks offer a con-
venient method of connecting to speaker cabinets
using cables terminated with 1/4 plugs. However ,
when using the amplifier at or near its full output power ,
using the five-way binding posts (domestic units) or Speakon
®jacks (export units) is recommended. The
binding posts/Speakon ®jacks must be used when
operating in the Mono Bridged mode. (See pages 21
and 22.) In the Mono Bridged mode, pin 1+ = +, pin 2+
= -“.
26. FULL RANGE/BIAMP: This switch determines how
the signal is sent to the internal amplifiers. In the Full
Range position (switch out), a full range signal is sent
to both amp channels. In the Biamp position (switch in), the low frequencies are sent to Channel A and the highfrequencies are sent to Channel B. (See pages 21 and
22.)
NOTE: When Biamping, the Stereo/Mono switch
(27) must be set to Stereo. (See pages 21 and 22.) 27. STEREO/MONO:
This switch sets the operating
mode of the amplifier. In the out position the amplifier is in the Stereo Mode; with the switch in the in posi -
tion the amplifier is in the Mono Bridged Mode. (See
pages 21 and 22.)
28,30. POWERAMPINPUTS: These jacks connect
directly to the power amp for use with external pre -
amps. When using external sources, connect the OUT-
PUTof the sources to these jacks using shielded instru -
ment cables to feed the signals into the power amp sec -
tions. The internal signal is disconnected when a plug is inserted. In the Mono Mode, Channel A = Input. In the
Biamp Mode, Channel A = Low Input, Channel B = High
Input. (See pages 21 and 22.)
29,31. PREAMPOUTPUTS These jacks are direct
preamp outputs for use with external power amplifiers, mixing boards, external effects, etc. Connect the exter-
nal unit inputs to these jacks using shielded instrument cables.
32. FOOTSWITCH: Connect a two button footswitch to
this jack for remote Mute and EQ On/Off control. On the stereo 1/4 plug, the tip controls Mute and the ring con-
trols EQ On/Off. When a footswitch is connected, the Mute switch (3) can still be used; however, the EQ
switch (12) is disabled.
33. BIAMP HIGH/LOWOUTPUTS: When using the
amplifier in the biamp mode, the Biamp High Out jack carries the high frequency signal and the Biamp Low
Out jack carries the low frequency signal. (See pages
21 and 22.)
34. LINE OUTLEVEL: This controls the strength of the
signal at the Line Out jacks (37,38) and works inde -
pendently from the Master control (14). 35. LINEOUT PRE/POSTSWITCH:
The signal at the
Line Out jacks can be set to either Pre or Post EQ with this switch. With the switch in the OUTposition, the sig -nal at the jacks will be Pre-EQ. This is a direct output
not affected by any preamp tone settings. With the switch IN, the signal is Post-EQ and is controlled and modified by the tone controls, Graphic EQ and the
effects loop.
36. LINE OUTGROUND LIFT:This switch disconnects
the ground pin of the line Out XLR jack (37), which may
help reduce residual hum and buzz sometimes picked
up in line out signal cables. The ground is lifted when the switch is depressed.
37,38. TRANSFORMER BALANCED LINE OUTJACKS: These jacks supply a pre-Master, line level
signal for connection to a house mixing board, record -
ing console or external amplifier(s). The XLR-type jack
(37) provides a balancedsignal; the 1/4 jack (38) pro -
vides an unbalanced signal. The signal level at these
jacks is controlled by the Line Out Level control (34)
and is governed by the Pre/Post switch (35).
39. EFFECTSLOOP RETURN:When using external
effects, connect the effects output into this jack using a shielded instrument cable.
40. EFFECTSLOOP SEND:When using an external
signal processor, connect this jack to the input of the
effect using a shielded instrument cable.
41. TUNEROUT :This jack is provided for connection
to an electronic tuner and is always live, even when
the Mute switch (3) is engaged, allowing for silent tun -
ing as well as a monitor feed which remains active
when the house mix is muted.
B-4R rear panel:
Technical Specifications (cont):
GRAPHIC EQ RANGE/LEVEL ±15dB @ 33Hz; ±10dB @ 80Hz, ±8dB @ 150Hz, 300Hz, 600Hz, 900Hz, 2kHz; ±10dB @ 5kHz; ±10dB @ 8kHz;
Level = ±6dB
SIGNAL TO NOISE RATIO 75dB typical
FOOTSWITCH JACKGraphic EQ On/Off, Mute On/Off -“ Tip = Mute, Ring = EQ
POWER REQUIREMENTS 120VAC, 60Hz, 800VA; 100VAC, 50/60Hz, 800VA; 230VAC, 50/60Hz, 800VA
SIZE AND WEIGHT 19 W x 5.6 H (w/feet) x 15.5 D, 43 lbs.
Page 2
In the example shown below, the B-4s two internal power amplifiers are bridged together to produce maximum output power. Set the Stereo/Mono Bridge switch to the IN (Mono Bridged) position and connect the system as follows:
1 : Connect a heavy duty speaker cable terminated with a Speakon
®connector or dual banana plugs from the B-4s Mono Bridge / Biamp Output jack to
the input jack of a speaker cabinet capable of handling the extremely high output power. (Speakon ®: pin 1+ = +, 2+ = -“; Banana: Mono +, Mono -“.)
In the example shown below, the B-4s two internal power amplifiers will each power a set of full range cabinets. Set the Stereo/Mono Bridge switch to the OUT (Stereo) position and connect the system as follows:
1 : Connect a speaker cable from the B-4s Power Amp A Speaker Output jack to the input jack(s) of a set of full range speakers.
2 : Connect a speaker cable from the B-4s Power Amp B Speaker Output jack to the input jack(s) of another set of full range speakers.
In the example shown below, the B-4s two internal power amplifiers will power both a full range cabinet and a low frequency cabinet. The crossover point is determined by the Biamp Frequency control (16).
Set the Stereo/Mono Bridge switch to the OUT (Stereo) position and connect the system as follows:
1 : Connect a shielded cable from the B-4s Biamp Low Out jack to its Power Amp A Power Amp In jack.
2 : Connect a speaker cable from the B-4s Power Amp A Speaker Output jack to the input jack of the low frequency cabinet(s).
3 : Connect a speaker cable from the B-4s Power Amp B Speaker Output jack to the input jack of the full range cabinet(s).
Mono
Bridged
Dual
Mono
Biamp: Full
Range / Lows
B-4R hookups:
