POWER 750 • 9
SPEAKER CABLE
The speaker cable you use to connect your SWR system should be made of at least 18 gauge wire, and heavier if possible. (The thicker the wire,
the lower the gauge, so 18 gauge is heavier than 20 gauge, 16 gauge is better than 18 gauge, and so on.) DO NOT use instrument cables to hook
up your speakers. This can result in intermittent power loss, cause the power amp to oscillate and damage itself and/or your speakers, and render
the cables useless for any purpose.
SPEAKER FUSE
The speaker fuse is provided to protect your speakers in the unlikely event of a power amp failure or incorrect connection procedure. Size and
rating of the fuse is 3AG, 15 amp, fast-blo. Do not defeat the purpose of this feature by using a higher rated fuse. The speaker fuses can open if
there is a fault in the speaker cable or even the speakers themselves. Therefore, it is always wise to carry extra fuses at all times. Do not defeat
the purpose of this feature by using a fuse of a higher amperage. It will only cause further problems if a fault lies in the system.
LINE (MAINS) FUSE
The size and rating of the Line Fuse is 3AG, 12 amp, slo-blo. It serves to protect your amplifier's power supply and transformer from large voltage
spikes caused by an external source, and also serves to protect the transformer in the unlikely event of a power supply failure. NEVER replace
this with a fuse of a higher rating as it will void your warranty.
A/C CORD RECEPTACLE
This receptacle accepts a standard A/C power cable (supplied with the Power 750), the same kind used with almost all current musical, profes-
sional and household electronic devices. If this cable is misplaced or lost, a replacement can generally be found almost any appliance store,
supermarket or the like. Make sure that the AC cord is plugged firmly into both the amplifier and the wall socket. If your cord ever becomes frayed
or split, replace it IMMEDIATELY.
NOTE: The rating for the A/C cable is 3 conductor, 10 amperes MINIMUM. If replacement is necessary, or if you wish to buy a longer cable, look
for the rating on the cable and be sure it is at least 10 amps.
COOLING FAN DEFEAT SWITCH
Your Power 750 features a cooling fan for protection against excessive heat. The "ON" position activates the fan in its normal operating mode. We
recommend leaving the fan switch set to the "ON" position for the majority of the time that the amplifier is in operation, as continuous cooling can
help extend the life of the internal components. The "DEFEAT" position removes the power source from the fan so that it will not operate. This posi-
tion should be used in situations where the noise floor is so low that normal fan noise would be noticeable or distracting, such as close miking in a
recording studio.
• Please note that it is normal for the cooling fan to be audible at low levels.
A FEW WORDS CONCERNING HEAT
One of the most asked questions about our amplifiers is why they tend to get warmer than other amps. The chassis of your amplifier can get quite
warm during normal usage. This is especially true if you are are driving the amplifier at its minimum impedance. This is because a 2.6 ohm imped-
ance introduces the least efficient condition possible for the unit (ie: power drawn from the outlet in relation to power produced in the speakers).
The difference in these two figures can be quite high,
Furthermore, most musical instrument amplifiers on the market today use steel for their chassis', which in most cases is considerably cheaper
than aluminum and does not conduct heat as well. The Power 750 utilizes an aluminum chassis (with the exception of the chromed front panel)
which is a better conductor of heat. This results in the chassis acting as a heatsink - drawing heat away from internal heat-producing components,
thus extending their life. In this manner we feel we have produced a more reliable amplifier, however, at the same time, the chassis of the Power
750 will get warmer than a similar amp chassis that is made of steel.
The one condition you should be aware of is if the power amplifier in your unit becomes "over-biased." This condition can be recognized by turn-
ing your amplifier on and letting it sit "idle" (without speakers plugged in and without playing it). If your unit starts getting hot under these condi-
tions, it may be over-biased. This situation should be attended to and can be easily remedied in about 15 minutes by a qualified service technician.
A power amp can become over-biased through continuous vibration or by any large jolt received in shipping, etc.