Setup
The initial setup of the amplifier is very straight-forward. Place the amplifier in
a well-ventilated location, as it draws about 180 watts during operation and
requires as much opportunity to cool itself as possible. You should be able to
put your hands on the heat sink during operation. If you can't do this for 5
seconds or so, they need more ventilation.
On the front panel there are two blue LED lights, one for each channel,
indicating power to the channel. On the rear panel you will find a pair of RCA
inputs, speaker outputs, a fuse holder, an AC power receptacle, and on/off
switch.
The label will indicate a serial number and also what AC line voltage the
amplifier is set for. If the voltage is 120 VAC, then the fuse value will be a 3AG
slow blow fuse rated at 2.5 amps. If the voltage is 240 VAC, then the fuse will
be rated at 1.25 amps. Do not substitute a larger value fuse. Contact First
Watt if you have any questions.
I'm assuming that you know how to attach the speaker cables to the 5 way
output connectors provided. Please make all the connections with the
amplifier power switch in the OFF position.
For two channel operation, input signal is connected to the RCA inputs. The
output connections to the loudspeakers are made through the gold plated
brass 5 way connectors. The red (top) connection is positive and the black
(bottom) is negative. In this amplifier the black banded output connectors are
connected directly to signal ground.
A caveat is in order here – this is a very wide band amplifier with a high input
impedance. In order to prevent the output voltage from bleeding back to the
input at very high frequencies (thus making a fine power oscillator), keep the
input and output cables separate, and don’t externally connect the speaker
ground to the input ground. Good ground shielding on the input cables is
important, and caution is called for in using Litz and other specially low
inductance / high capacitance cables. I have not seen a specific example of a
problem, but historically it is to be expected when an amplifier’s bandwidth
exceeds 200 KHz. If the amp makes funny noises, runs extra hot, or blows
fuses, this might be an indicator of such an issue.
If you have any questions, just drop me an email: nelson@passlabs.com
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