Crate Amplifiers SPA100 manual Front Panel Information

SPA100 1 / 2 - R a c k P o w e r A m p l i f i e r

Front Panel Information:

Power

On

Off

Power Signal Limit Protect

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1:POWER SWITCH: This switch applies AC power to the amplifier. The amp is on when the top of the switch is depressed, off when the bottom of the switch is depressed. The Power LED indicator (#3) illuminates when the ampli- fier is on.

2:LEVEL CONTROL: This rotary potentiometer controls the level or gain of the amplifier, with the fully-clockwise position providing a sensitivity of +2dBv. Normal calibra- tion of the SPA100 to a mixer would cause the Peak LED to flash at the same time that the mixer’s VU meters indi- cate full output.

3:POWER LED: This LED illuminates when AC power is applied by means of the Power switch (#1). If the LED fails to illuminate, check the AC outlet or the fuse on the rear panel (#13).

4:SIGNAL LED: This LED illuminates when a signal is detected at the amplifier’s output terminals. The level of the signal must be at least 1% of the amplifier’s full rated output to cause the LED illuminate.

5:LIMIT LED: The SPA100 employs an internal limit cir- cuit to alert the user if the amplifier is approaching clip- ping. The Limit LED illuminates whenever the input signal attempts to overdrive the amplifier. (Not only does clip- ping produce harsh sounding distortion, it is also capable of damaging speaker components – particularly high fre-

quency drivers.) Periodic flashing of the Limit LED indi- cates operation at or near full output. This is normal. Steady illumination of the LED indicates constant opera- tion of the Limiter, with the possibility that the input sig- nal should be reduced by means of the Level control (#2).

6:PROTECT LED: This LED illuminates whenever the inter- nal protection circuit is activated. The protection relay is activated for a short period upon initial turn-on and at turn- off to prevent transient “spikes” from being reproduced through your speakers. A fault condition is also indicated in the event of an overtemperature status, or if DC voltages are present at the output. During thermal protection, the output is shut down until the temperature returns to a safe operating level. In the event of DC voltage on the output, the output will be internally disconnected. The circuitry associated with the LED indicator provides valuable pro- tection for both the amplifier and your speakers.

7:FRONT PANEL EXHAUST VENT: The SPA100 employs a variable-speed internal cooling fan to draw air through the unit to keep it running cool even under extreme operating conditions. Air is drawn in through the unit’s rear and side intake vents and is forced out through the front panel exhaust vent. Keep these vents clear and free from obstruc- tion at all times to insure proper cooling.

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