| 1: COOLING FAN EXHAUST VENT: The SPA-1400/1400C employs a pair of variable-speed internal cooling fans to draw air through the unit and keep it running cool even under extreme operating conditions. The air is drawn in through the unit’s side and rear intake vents and is forced out through the front panel exhaust vent. This method of cooling draws air out from the interior of the rack and provides more efficient cooling than methods which bring air in from the front and exhaust it through the back. Keep these vents clear and free from obstruction at all times to insure proper cooling. |
| 2: PROTECT INDICATOR LEDS: These LEDs will illuminate whenever the internal protection relay for the channel 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 protect condition is also indicated if the unit gets too hot, or if DC voltages are present at the output. During thermal protection, both channels are shut down until the temperature returns to a safe operating level. In the event of DC voltage on the output, only the affected channel will be disconnected. The circuitry associated with the LED indicators provides valuable protection for both the amplifier and your speakers. |
| 3: LIMIT INDICATOR LEDS: The SPA-1400/1400C employs an internal "Automatic" limit circuit to prevent the amplifier from clipping. The Limit LEDs will illuminate whenever the input signal attempts to overdrive the amplifier’s output section, indicating that the Limiter has been called upon to prevent clipping. (Not only does clippingproduce harsh sounding distortion, it is also capable of damaging speaker components – particularly high frequency drivers.) Periodic flashing of the Limit LEDs indicates operation at or near full output and is no cause for alarm. Steady illumination of one or both LEDs indicates constant operation of the Limiter, with the possibility that the input signal should be reduced by means of the Level control (#15, rear panel). The Limiter within the amplifier is fully automatic, insuring you complete protection against clipping at all times. |
| 4: SIGNAL INDICATOR LEDS: These LEDs will illuminate when signal is detected at the amplifier’s output terminals, providing accurate visual confirmation of signal presence, which is helpful in hookup and troubleshooting. The output signal must be at least 5% of the amplifier’s full rated output to make the LEDs glow. |
| 5: POWER INDICATOR LED: This LED will illuminate when AC power is applied by means of the POWER SWITCH (#7). If the LED fails to illuminate, check the AC outlet or the RESET SWITCH (#6). |
| 6: RESET SWITCH: The SPA-1400/1400C employs an AC line circuit breaker to help protect against damages due to excessive current demands. If the amplifier does not function, check the circuit breaker. If it has opened, the button will be protruding and showing a contrasting color. You may reset it by pressing the button in until it latches. The circuit breaker must cool down for a short time before the button will latch. If the circuit breaker opens repeatedly with no signal input, have the amplifier checked by a qualified service person. |
| 7: POWER SWITCH: This switch turns the amplifier on in the up position ("I" pressed in) and off in the down position. When AC power is applied to the amplifier, the POWER INDICATOR LED (#5) will illuminate. |
| 8: REAR SUPPORT HOLES: Use of a rear support system is strongly recommended when installing the amplifier, especially in a rack mount situation. Please see page 23 for more information. |
| 9: FAN INTAKE AREAS: Air for cooling the SPA-1400/1400C is drawn in by the fan at the rear and side, directed through the amplifier, and exhausted through the front panel vent. Do not block the airflow through these vents and do keep the area free of foreign materials. |
| 10: POWER CORD: This heavy duty power cord must be connected to a grounded AC outlet of the proper voltage for the amplifier to operate. TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE OR BYPASS THE GROUND PRONG OF THE POWER CORD. |
| 11: SPEAKON ® OUTPUT JACKS: These heavy-duty output jacks are to be used to connect the amplifier to your speakers using cables terminated with Speakon ® type plugs. These jacks are wired in parallel with the BINDING POSTS: The channel 1 and 2 Speakon ® jacks are wired with pin 1+ "positive" or "in phase", and pin 1– "ground" or "out of phase" (wired 1+/1–). The MONO/BIAMP jack has channel 1 wired 1+/1– and channel 2 wired 2+/2–; mono wiring is to 1+ and 2+, with 1+ "in phase". (See pages 8–20 for more information.) |
| 12. 5 WAY BINDING POST OUTPUTS: These output connectors offer an excellent method of connecting the amplifier to your speakers using cables terminated with spade lugs, banana plugs, or bare wire. When using the amplifier in the Mono Mode, you must use either the two red binding posts or the BIAMP/MONO (middle) Speakon ® jack (#11). The Binding Posts are wired in parallel with the Speakon ® jacks. |
| 13: XLR BALANCED INPUT JACKS: These jacks will accept any balanced or unbalanced low or medium impedance line level source by means of a three-pin XLR plug. The wiring for the plug is as follows: Pin 1 = Ground, Pin 2 = Signal "+", Pin 3 = Signal "–". |
| 14: 1/4" PHONE JACK INPUTS: These jacks accept line level signal sources by means of cables fitted with standard 1/4" phone plugs. Low or medium impedance balanced or unbalanced sources are acceptable for these inputs. Balanced inputs are wired as follows: Tip = Signal "+", Ring = Signal "–", Sleeve = Ground. Unbalanced inputs may be wired Tip =Signal, Sleeve = Ground, using a "mono" plug. Note: The input channel circuitry is transformerless electronically balanced, and requires a line level signal of 1.1V RMS or greater to drive the amplifier to full output. |
| 15: LEVEL CONTROL: These rotary potentiometers control the sensitivity or gain of each channel. Set them to the level needed for the desired output – watch the LIMIT and SIGNAL LEDs on the front panel for guidance (see #3 and #4, front panel). |
| 16: PARALLEL MONO SWITCH: This push/push switch parallels the amplifier channel inputs. In the "out" position (switch button about flush with chassis) the amplifier is in the Stereo Mode; with the switch pressed in (switch button indented below surface of chassis) the amplifier is in the Parallel Mono Mode. In the Parallel Mono Mode, connect the input to Channel 1 (Channel 2’s inputs are disconnected). The signal is internally split and sent to each amp channel; the output signals at all speaker jacks are in the same phase. Each level control still controls its channel’s output in this mode. |
| 17: BRIDGE MONO SWITCH: This push/push switch connects the channels to work together for more power output. In the "out" position (switch button flush with chassis) the amplifier is in the Stereo Mode; with the switch pressed in (switch button indented below surface of chassis) the amplifier is in the Bridge Mono Mode.
In the Bridge Mono Mode, connect input to Channel 1 (Channel 2’s inputs are disconnected). Both amp channels are internally bridged together to create a single-channel amplifier of increased output power. |
| Use the two red BINDING POSTS (labeled "Mono/ Biamp") or pins 1+/2+ of the BIAMP/MONO (middle) Speakon® jack. Only Channel 1’s Level control is active in this mode, and channel 2’s output is 180 o out of phase with channel 1’s. |
18: BALANCED THRU/X-OVER OUT JACKS: These male XLR jacks are independently switchable and have two uses:(1) Balanced Thru: For driving additional amplifiers with the same input signal, set the X-OVER OUT/THRU switch (#19) to the THRU position (switch out). This places its corresponding Balanced Thru/X-Over Out jack in parallel to the same channel’s XLR and 1/4" input jacks. Connect a balanced cable with XLR plugs from the Balanced Thru/X-Over Out jack of the first amplifier to the input jack of the next. Wire the cable as follows: pin 2 = "+", pin 3 = "–". (2) Crossover Out: To send the crossover output signal to an external amplifier, set the X-OVER OUT/THRU switch (#19) to the X-OVER OUT position (switch pressed in). Connect a balanced cable with XLR plugs from the Balanced Thru/X-Over Out jack of the first amplifier to the input of the other amplifier. Whether the jack carries the low or high frequency signal is dependent upon the setting of the CROSSOVER HI/LOW SEND switches (#22).
19: X-OVER OUT/THRU SWITCH: These switches set the operating mode for the Balanced Thru/X-Over Out jacks (#18). Set the switch "out" (flush with the panel) for Balanced Thru operation; press the switch in (recessed into the chassis) for Crossover Out operation.
20. LOW CUT FREQUENCY CONTROLS: These controls adjust the cut-off frequency of the low cut filters (when active – see #21). Use a small flatblade screwdriver to adjust the controls. The cut-off range is from 10Hz (full counter-clockwise) to 150Hz (full clockwise).
21: LOW CUT SWITCHES: These pushbutton switches activate the low cut filters when pressed in. The cut-off frequency is determined by the setting of the LOW CUT FREQUENCY control (#20).
22: CROSSOVER LOW/HI SEND SWITCH: This pushbutton switch determines where the low and high crossover signals are sent: Switch IN: Low to channel 2, High to channel 1 (2/1) Switch OUT: Low to channel 1, High to channel 2 (1/2)
23: CROSSOVER MODE SWITCH: This switch determines whether the amplifier channels are driven from the crossover outputs or from the normal input signal. With the switch in the "off" position (pressed out), the amp is driven normally. With the switch in the "on" position (pressed in), the channel 1 input signal is split into a low frequency and a high frequency signal. One signal is sent to the amp’s channel 1 outputs, the other to its channel 2 outputs, depending on the setting of the LOW/HIGH SEND switch (#22). (See the additional information below.)
24: CROSSOVER FREQUENCY CONTROL: This control adjusts the crossover frequency (when active – see #23). Use the tip of a small flatblade screwdriver to adjust the control, from 45Hz (full counterclockwise) to 2500Hz (full clockwise).
More About the Crossover: The electronic crossover is ideal for use with subwoofers and may also be used to crossover from low to mid, mid to high or low to high on biampable speakers.The input signal to the crossover is taken from channel 1, after the LOW CUT filter. The crossover output may be used internally, externally, or both, by use of the LOW/HI SEND switch (#22), the BALANCED THRU/X-OVER OUT jacks (#18), and the X-OVER OUT/THRU switches (#19). A signal can be sent to a completely separate amplifier if desired (see page 17).
Note: Regardless of the setting of the CROSSOVER MODE switch (#23), you can still take a line level crossover output
signal from the BALANCED THRU/X-OVER OUT jacks (#18). The X-OVER OUT/THRU switch (#19) must be set to "X-Over Out" (pressed in), and the LOW/HI SEND switch (#22) will determine where to tap the low and high frequency signals (ie, lows to channel 2, highs to channel 1 when the switch is pressed in). The crossover is always active, even if it is not selected "on" for internal use.