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Multi-Channel Design: The Boston GTA 704 is a 4-channel
amplifier, basically two independent 2-channel amplifiers built into one chassis.
Either side can be bridged so it can be used as a 4-channel, 3-channel, or
2-channel amplifier. The amplifier is stable down to 2-ohms in stereo, and
4-ohms when bridged.
CEA 2006 Compliant: The GTA 704's power ratings are measured
according to the Consumer Electronics Association CEA-2006 standards. These
standards allow you to accurately compare the rated power output of all CEA
2006-compliant amplifiers, even different brands. Manufacturers who adhere to
the standards can display the CEA 2006 logo on their products and packaging. The
power output is measured from 20 Hz to 20 kHz using a 14.4 volt power supply:
- Four-Channel (4-ohm): 70 watts x 4-channels
into 4-ohms with no more than 1% THD+N
- Four-Channel (2-ohm): 125 watts x 4-channels
into 2-ohms with no more than 1% THD+N
- Bridged (4-ohm): 250 watts x 2-channels into
4-ohms with no more than 1% THD+N
Controls and Terminals: All the controls and terminals are
conveniently mounted on one side of the amp.
Gain: The amplifier's gain setting is adjusted using two
independent rotary controls for the front and rear channels. The line-level
input gain settings are continuously variable from 200 mV to 5.0 V; the
speaker-level input gain settings are continuously variable from 400 mV
to 10.0 V.
Crossover Switches: There are also independent crossovers
for the front and rear channels; each can be set to HP (high pass), Off (full
range), or LP (low-pass).
Crossover Frequency: You can independently select the crossover
frequency for the front and rear channel crossovers; each is continuously variable
from 50 to 200 Hz. The crossover slope is 12 dB/oct.
Q-Tune: Q-Tune bass boost can be applied to the rear channels;
the boost is +6 dB at 45 Hz and can be turned off if you prefer.
Speaker-level Input: Front and rear speaker-level input harnesses
(included) supply signal to the amp when the receiver has no RCA outputs.
Line-level Input: The front and rear amplifier sections have
independent RCA input jacks.
GTA-RSL: RJ-14 port; connect an optional GTA-RSL remote level control (item number
065GTARSL, sold separately); the GTA-RSL is attached to the rear channels
and only functions when the low-pass crossover is engaged.
Speaker Output: Four pair of set-screw terminals are provided
for connecting the speakers; the terminals accept up to 10-gauge wire; the set
screws are tightened/loosened with the supplied 2mm Allen wrench.
ATO Fuse: Two 25-amp ATO-type fuses are located between the
speaker and power terminals.
Power/Remote: The power, ground, and remote wires connect to
three set-screw terminals. Each terminal accepts up to 8-gauge wire and the set
screws are tightened/loosened with the supplied 3mm Allen wrench.