10
II. CROSSOVER— (Bi-amplifier control) Sets the frequency at
which your signal is split into high and low components. This
always affects the Low and High Out {GG and JJ} jacks. This only
affects the *LF and *HF speaker Outputs {OO and RR} when *Bi-
Amp mode {HH} is selected.
JJ.
HIGH OUT— TRS1 line level, 1/4" output. Supplies high frequen-
cies; useful for connection to an external power amplifier in a
bi-amp configuration. NOTE: This output is always active, inde-
pendent of the positions of the mode switches {HH and PP}.
KK.
TUNER OUT— Plug your instrument tuner in here. This TRS1
output can also be used as an always-active, tube-influenced
direct output.
LL.
IN— An alternate input to input 1 on the front panel; useful for
wireless receivers. This input is disabled when a plug is inserted
into input 1 on the front panel.
MM.
MAIN BREAKERS— Protects the power amplifiers from electri-
cal faults and circuit overloads. If a breaker has tripped (button
pops out), switch the Power {Z} OFF and allow the unit to cool
down. Inspect your speakers, all connections and other equip-
ment for damage before pressing each circuit breaker back in
to reset them.
NN.
POWER CORD SOCKET— Connect the included** power cord
to a properly wired AC electrical outlet in accordance with the
voltage and frequency ratings specified on the rear panel of
your amplifier.
** The SM-1500 uses a heavy duty power cord to supply the
high power requirements. To ensure safe operation: If
an extension cord is required, use only one extra-heavy
gauge cord (10 AWG or heavier) that is no longer than
absolutely necessary.
OO.
PARALLEL RIGHT (LOW FREQUENCY) SPEAKER OUTPUTS—
Connect right channel (or low frequency) speakers to these
three jacks in any combination. The total impedance load of
these speakers should ideally be 2 ohms and must never be less
than 2 ohms. The power handling capacity of these speakers
must be at least 750 watts.
The SM-1500 furnishes both 1/4" and Speakon® speaker con-
nections. Use the Speakon® jacks whenever possible to take
advantage of their superior electrical efficiency and secure
connectors. All three jacks on each side are full range and wired
in parallel. Read the Speaker Guidelines section below before
connecting speakers.
PP.
NORMAL / BRIDGE SWITCH— Selects a core mode of opera-
tion for the SM-1500 power amplifiers. Each mode uses different
speaker outputs and master volumes. Turn OFF the SM-1500 while
switching modes and connections. Use the tip of a pen to reach the
recessed button:
• Normal Mode—The power amplifiers operate separately as
right and left channels (in Stereo mode {HH}) or as low and high
channels (in Bi-Amp mode). In Normal Mode: use the Parallel
Right (*LF) and Left (*HF) speaker Outputs {OO and RR} and
both Volume knob {Y} sections.
• Bridge Mode—The power amplifiers are bridged together to
operate as one monolithic power block. In Bridge mode: use
the one center speaker output {QQ} and the inner Volume {Y}
knob alone.
QQ.
MONO (BRIDGE) MODE SPEAKER OUTPUT— One Speakon®
speaker output jack is available in Bridge Mode. The total
impedance load of this speaker(s) should ideally be 4 ohms and
must never be less than 4 ohms. The power handling capacity
of this speaker(s) must be at least 1500 watts. Read the Speaker
Guidelines section below before connecting speakers.
RR.
PARALLEL LEFT (HIGH FREQUENCY) SPEAKER OUTPUTS—
Connect left channel (or high frequency) speakers to these
three jacks in any combination. The total impedance load of
these speakers should ideally be 2 ohms and must never be less
than 2 ohms. The power handling capacity of these speakers
must be at least 750 watts.
1TRS Balanced Jacks
NOTE: Jacks {FF, GG, JJ and KK} are balanced TRS (Tip/Ring/Sleeve) types and are designed
to accept either TRS or TS (Tip/Sleeve) plugs:
Tip=positive (+)
Ring=negative (–) and
Sleeve=ground.
While standard shielded TS "mono" guitar cables may certainly be used, the use of "stereo" TRS cables may improve signal-to-noise ratio
and/or reduce hum, especially when longer connections are required.