Fender Twin Amplifier - Manual (Page 6)

of the slave amps such that they NEVER clip with full output from the
Twin. Here’s why: Since the signal at the BALANCED LINE OUT is
derived directly from the output transformer, the signal is a replica of
the voltage present at the speakers in the Twin. If the output of the
slave amps never clip, then the voltage at the output of the slave
amps will also be a replica of that on the speakers in the Twin. This
will preserve the Twin sound. As for the 300 watt minimum rating...
In order for a “slaved” solid-state amp to reproduce the sound of a
tube master amp, a solid-state amp needs lots of headroom. For
example, because of the way a tube amp interacts with a speaker
load, a 20 watt tube amp, when driven into heavy clipping, can pro-
duce output signals equivalent to a 180 watt solid-state amplifier.
This nine-to-one ratio can get excessive when a 100 watt tube master
amp is used. But, if the solid-state slave amp has enough headroom
to never clip, and if the speakers used on the slave amp are the same
as those used in the Twin, voila! You now have the capability of
obtaining large amounts of on-stage Twin sound. We recommend
using a Fender Electronics SPL9000(s) with an additional Fender
speaker enclosure(s).
If the BALANCED LINE OUT is used as a send to a mixing console, it
should normally be pre-equalized before going to the console input.
What works well is to run the BALANCED LINE OUT signal through
a low-pass filter set to 5 to 6 kHz. The slope of the filter needs to be
steep, 18 dB per octave minimum. A handy way to do this is to use
the low-pass output of an active crossover, or to use a parametric
equalizer. By tweaking the equalization, some very useful sounds
can be obtained.
Q. EXT. SERIES JACK — Plug-in connection for extension speakers.
This should be used in conjunction with the MAIN SPEAKER jack
(item R). By using the EXT. SERIES JACK, the extension speaker is
placed in series with the main speaker; therefore, the impedance of
the extension speaker adds to that of the main speaker. For exam-
ple, by connecting a 4 ohm speaker to each jack, the total load is
4+4=8 ohms. The IMPEDANCE SELECTOR switch (item T) would
then be set to 8 ohms. (Note: an additional 8 ohm speaker could be
added to the EXT. PARALLEL JACK (item S) for a total of 4 ohms, with
the IMPEDANCE SWITCH set accordingly.)
R. MAIN SPEAKER JACK — Plug-in connection for speakers. For
proper operation, this jack should always be used first as connection
to the primary speaker(s). If this jack is used alone, set the IMPED-
ANCE SELECTOR switch (item T) to equal the total speaker load
impedance connected to it.
S. EXT. PARALLEL JACK — Plug-in connection for extension speak-
ers. This jack should be used in conjunction with the MAIN SPEAKER
JACK (item R). By using the EXT. PARALLEL JACK, the extension
speaker will be placed in parallel with the main speaker; therefore,
reducing the total load impedance. For example, by connection a
16 ohm speaker to the MAIN SPEAKER JACK and a 16 ohm speaker
to the EXT. PARALLEL JACK, the total impedance will be
(16X16)/(16+16)=8 ohms. The IMPEDANCE SELECTOR SWITCH
(item T) would then be set to 8 ohms. (Note: An additional 8 ohm
speaker could be connected to the EXT. SERIES SPEAKER JACK (item
Q) for a total load of 16 ohms, with the IMPEDANCE SWITCH set
accordingly.)
T. IMPEDANCE SELECTOR SWITCH — Sets the output impedance of
the amplifier. The setting should equal the total load impedance as
determined above using the three speaker jacks. (The Twin is sup-
plied with two 8-ohm speakers connected in series; therefore, the
IMPEDANCE SELECTOR SWITCH is set to 16 ohms at the factory.)
LOW POWER OPTION
The Fender Twin can be run with only two output tubes instead of
four. This is done by removing the inner two 6L6GC tubes (the 2nd
and 3rd large tubes, counting left to right), and setting the IMPED-
ANCE SELECTOR SWITCH to one-half of the total speaker load; e.g.,
with a total speaker load of 16 ohms connected, the OUTPUT IMPED-
ANCE SWITCH should be set to 8 ohms. (Remember — half the
tubes, half the impedance.) This will produce 60 watts RMS in the
OUTPUT HIGH setting, and 15 watts RMS in the OUTPUT LOW setting.
LINE CORD
Your amplifier is equipped with a grounding type supply cord to
reduce the possibility of shock hazard. Be sure to connect it to a
grounded AC receptacle. DO NOT ALTER THE AC PLUG.
TUBES
The Fender Twin tube complement consists of four Fender Special
Design 6L6WGC/5881’s (part number 039214), three Fender
Special Design 12AT7’s (part number 023531), and five 12AX7A’s
(part number 013341). Fender’s Special Design Tubes provide opti-
mum performance in the amplifier. For best results, replace with
Fender original equipment tubes only. Tube location lable is in cabinet.
BLACK TOLEX COVERING CARE
The exclusive Fender Tolex covering on your cabinet is especially
designed to provide years of lasting beauty. A very light soapy solu-
tion on a sponge may be used to remove dirt and residue that may
accumulate in the grain. Be careful not to let any liquid come in con-
tact with the operating surfaces. DO NOT have the amplifier
plugged into a power outlet when cleaning.
TROUBLESHOOTER’S CHECKLIST
- Is the power cord properly plugged into an electrical outlet?
- Is there power at the outlet?
- Is the fuse blown?
- Is the speaker(s) properly connected to the amplifier?
- Is the amp on standby?
- Are all the control knobs turned up above “4”?
- Is the volume control on the instrument turned up?
- Is the instrument plugged into the amplifier?
(Eliminate any effects devices and try another cord.)
If, after checking all of the above, the system is still not operating
properly, consult your authorized Fender Service Dealer.