SPELLBINDER BLUE™
(This is the model name for warranty claims)
6
are: TUNER_RP, EFX_RTN-, EFX_RTN+,
LINE_RP, MUTE_RP, HEADPHONE, EFX_SEND+,
and EFX_SEND-. There is also +/-15V as well as
analog ground.
TUNER_RP feeds both the tuner output buffer at
U1B as well as the DIRECT signal for the BAL-
ANCED LINE OUTPUTS. The DIRECT or LINE_RP
signal is selected using S1, and is muted by FETs
Q1 and Q2. The signal is then buffered at U1A,
where the PAD control (R4) sets the output level. A
balanced line driver DRV134 (U2) is employed to
produce a high quality signal at both the balanced
¼” (J3) and XLR jack (J7).
The HEADPHONE output (J5) employs a paralleled
pair of 4560 opamps to obtain high current drive
capability for all types of headphones.
XOVER PCB:
The speaker crossover components are located on
the XOVER PCB, inside the speaker cabinet. L1 is
a -6dB/octave low-pass filter for the 10” speaker
and C3 is a -6dB/octave high-pass filter for the
Horn. A 50W L-PAD (connected to the PCB via
wires) controls the volume of the Horn.
160W Power Amp:
The power amp assembly is the Bang & Olufsen
50ASX2. This is a complete power supply and 160
Watt amplifier on a single PCB Assembly. The
power amplifier is produced and tested independ-
ently, and is a non-serviceable part.
The amplifier output connects to the Internal
Speaker On/Off switch and Speakon jack via the
twisted pair black and white wires, which are termi-
nated with insulated faston receptacles. The
Speaker Output ground can not, must not, ever
connect to Preamp ground or chassis ground.
Doing this will immediately destroy the power
amp module. Be careful when connecting test
equipment (such as oscilloscopes) to the
speaker output ground, as this can result in a
connection to Earth ground.
The power amp module also produces a low volt-
age +/-25V supply at P103. This low voltage supply
is made available to the Ancillary Power Supply
(Fender p/n 0076036000), which in turn produces
the other voltages needed by the Preamp circuits.
See the Ancillary Power Supply section for more
information.
Ancillary Power
Supply:
The Ancillary Power Supply is a non-serviceable
switching power supply module that takes the +/-
25V AUX Supply output from the B&O 50ASX2 and
creates the following voltages: +300V (Tube), 12.6V
(Tube Heater), and +/-15V (Preamp Op amps). The
module must be loaded to get the correct voltages
out of it, so do not operate it with the 6 pin header
unconnected.
To Next Page
Loading...
