SHOW SPA-4 Mixer Preamplifier User Manual
- June 2, 2024
- SHOW
Table of Contents
SHOW SPA-4 Mixer Preamplifier
Product Information
Specifications:
- Model: SPA-4 Mixer Preamplifier
- Channels: 5 (CH 1-CH 5)
- Zone Selectors: Z1, Z2, Z3, Z4
- Volume Control Range: 0 to +10
- Gain Range: -10 to +20
- High-Frequency Range: -10 to +10
- Low-Frequency Range: -10 to +10
Product Usage Instructions
Control Elements:
The mixer preamplifier features individual controls for each channel and zone
selector. Adjust the Gain, High, Low settings for each channel using the
provided knobs.
Connection Description:
Connect your audio sources to the respective channels on the mixer
preamplifier. Use balanced outputs when available to drive the speakers and
prevent issues like hum or buzz.
Volume Control:
Adjust the volume for each zone using the dedicated volume control knobs. The
range is from 0 (minimum) to +10 (maximum) volume level.
Troubleshooting:
If you encounter issues like no sound or distorted signal, refer to the
troubleshooting section in the manual. Check connections, power supply, and
signal sources for proper functionality.
FAQ:
-
Q: What should I do if there is no sound from the speakers?
A: Verify that the amplifier is connected, the power is switched on, and check for faulty cables or blown fuses. Ensure the signal source is sending audio and that the mixer controls are properly adjusted. -
Q: How can I reduce hissing in the sound?
A: Ensure proper gain adjustment and settings on the mixer. Avoid ground loops and adjust input sensitivity, channel faders, and master faders as needed. Also, consider using balanced outputs and proper cable management. -
Q: What should I do if the signal sounds distorted and very loud?
A: Reduce the output level of the source, turn down level controls on the speaker, and use additional speakers if necessary to prevent exceeding their capabilities.
SAFETY-RELATED SYMBOLS
- The symbol is used to indicate that some hazardous live terminals are involved within this apparatus, even under normal operating conditions.
- The symbol is used in the service documentation to indicate that specific component shall be only replaced by the component specified in that Documentation for safety reasons.
- Protective grounding terminal.
- Alternating current /voltage.
- Hazardous live terminal.
- ON: Denotes the apparatus turns on.
- OFF: Denotes the apparatus turns off, because of using the single pole switch, be sure to unplug the AC power to prevent any electric shock before you proceed your service.
WARNING: Describes precautions that should be observed to prevent the danger of injury or death to the user.
Disposing of this product should not be placed in municipal waste and should be separate collection.
CAUTION: Describes precautions that should be observed to prevent danger of the apparatus.
WARNING
- Power Supply
- Ensure the source voltage matches the voltage of the power supply before turning ON the apparatus.
- Unplug this apparatus during lightning storms or when unused for long periods.
- External Connection
- The external wiring connected to the output hazardous live terminals requires installation by an instructed person, or the use of ready-made leads or cords.
- Do not Remove any Cover
- There are maybe some areas with high voltages inside, to reduce the risk of electric shock, do not remove any cover if the power supply is connected.
- The cover should be removed by the qualified personnel only.
- No user-serviceable parts inside.
- Fuse
- To prevent a fire, make sure to use fuses with specified standards (current, voltage, type). Do not use a different fuse or short-circuit the fuse holder.
- Before replacing the fuse, turn OFF the apparatus and disconnect the power source.
- Protective Grounding
- Make sure to connect the protective grounding to prevent any electric shock before turning ON the apparatus.
- Never cut off the internal or external protective grounding wire or disconnect the wiring of the protective grounding terminal.
- Operating Conditions
- This apparatus shall not be exposed to dripping or splashing and no objects filled with liquids, such as vases, shall be placed on this apparatus.
To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture. Do not use this apparatus near water. Install by the manufacturer’s instructions. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat. Do not block any ventilation openings. No naked flame sources, such as lighted candles, should be placed on the apparatus.
IMPORTANT SAFETY INSTRUCTIONS
- Read these instructions.
- Follow all instructions.
- Keep these instructions.
- Heed all warnings.
- Only use attachments/accessories specified by the manufacturer.
Power Cord and Plug
Do not defeat the safety purpose of the polarized or grounding-type plug. A
polarized plug has two blades with one wider than the other. A grounding-type
plug has two blades and a third grounding prong. The wide blade or the third
prong are provided for your safety. If the provided plug does not fit into
your outlet, consult an electrician for replace-ment of the obsolete outlet.
Protect the power cord from being walked on or pinched particularly at plugs,
convenience receptacles, and the point where they exit from the apparatus.
Cleaning
When the apparatus needs cleaning, you can blow off dust from the apparatus
with a blower or clean with rag etc. Don’t use solvents such as benzol,
alcohol, or other fluids with very strong volatility and flammability for
cleaning the apparatus body. Clean only with a dry cloth.
Servicing
Refer all servicing to qualified personnel. To reduce the risk of electric
shock, do not perform any servicing other than that contained in the operating
instructions unless you are qualified to do so. Servicing is required when the
apparatus has been damaged in any way, such as a power supply cord or plug is
damaged, liquid has been spilled or objects have fallen into the apparatus,
the apparatus has been exposed to rain or moisture, does not operate normally,
or has been dropped. The mains plug is used as the disconnect device, the
disconnect device shall remain readily operable.
CONTROL ELEMENTS
The Front panel
-
Gain knob
this knob controls input gain. Turn the knob clockwise, then the input increases. Turn the knob counter-clockwise, then the input decreases. -
High knob
This is the treble control. You can use it to get rid of high-frequency noises or to boost the sound of cymbals lor the high harmonics of the human voice. The gain range goes from – 10 dB to 10 dB with the central frequency 10kHz. -
Low knob
This is the Bass control. Boost male voice or kick drum and bass guitar. Your system will sound much bigger than what it is. The gain range goes from -10dB to +10dB and the center frequency is 100 Hz. -
VOL knob
This knob controls volume. Turn the knob clockwise, and the volume increases. Turn the knob counterclockwise, and the volume decreases. -
Zone selector
Z1, Z2, Z3, Z4 can be considered as signal assignment switches. Press the button Z1 down and signal will be assigned to ZONE 1. Release the button and it stops assign signal to ZONE 1. Z2, Z3, Z4 can be operated in the same way. -
Phone Volume
This knob controls the volume of Phone (refer to 7). Turn the knob clockwise, and it increases the volume, and vice versa. -
Phone
The signals of amplifier can be sent to a pair of headphones through this socket. -
Monitor Volume
This knob controls the output signal level to monitor output. -
Zone1 VOLUME
VOLUME controls the output signal level of ZONE1. -
LED VU-meter
This stereo 6 segment LED meter indicates the level of the overall output signal. -
MONITOR selector
Push MONITOR button down, then it connects the signal from amplifier 1 to monitor volume. Release the button, then it cuts off the signal connection to monitor volume. The other three buttons are operated in the same way. -
PL
This LED is the power indicator. When the amplifier is powered on, this LED lights up. When the amplifier is powered off, this LED lights off. PL -
Power switch
When the switch is set in the position ON, the unit is powered on. When the switch is set in the position OFF, the unit is powered off.
The Rear Panel
-
AC Input
Power inlet This inlet connects the unit with the main power. -
AC fuse
The fuse protects the alternating current circuit of the unit, and the fuse can only be replaced in the event of fuse damage. -
AC Voltage Selector
When the AC Voltage Selector is set to the left 115V, it selects the power at 100V to 127V. When the AC Voltage Selector is set to the right 230V, it selects the power at 220V to 240V. -
Monitor Line Out
Monitor Line Out can be connected with other equipments, such as amplifier, recorder, etc. -
Monitor 1W8
The terminal is meant for the connection of a small external loudspeaker that gets driven by an internal auxiliary power amplifier, providing a nominal output 1Watt. Only the mixed audio signal coming from “AUX IN” are included in the outputted signal. In addition, the output signal is controlled only by the volume control of the “CH4”, “CH5”, music signal level control. -
“Priority” Terminal.
When these terminals are short-circuited (i.e. By means
of using an electrical switch), the audio signals coming from “CH4”, “CH5″, are attenuated while the signals coming from”CH1”, “CH2″,”CH3” are gaining priority. -
Input “AUX Paging”
The terminals input lets you connect to an auxiliary signal. The input features “Voice Priority” function, which overrides all other input signals once, an auxiliary message is sent. If you want to have this function disabled forever, please contact a distributor. -
a. Zone
There are four dip switches here. Push the dip switch up, it switches off and vice versa.- b.Volume
It controls the volume of sound source that is connected to the “Tel Paging”.Turning the knob clockwise increases the volume of the corresponding source. It is recommended to leave the control of momentarily not used input at their minimal setting “0”.
- b.Volume
-
‘LINE IN” inputs
an audio source with a high-level output signal, such as an AM/FM tuner, a cassette deck, a CD player, etc. Use input sensitivity switch suitable for difference appliances. They can take RCA-type coaxial connectors, and unbalanced signals. -
The mono MIC/LINE channels
These are the channels from Channel 1 to Channel 4. You can connect balanced, low-impedance microphones to the XLR socket. On the 1/4″ phone jack you can connect either a microphone or a line-level instrument. You shall never connect an unbalanced microphone to the XLR socket if you do not want to damage both the Microphone and the Mixer. -
CH1, CH2, CH3 and CH 4 inputs sensitivity and XLR phantom switch By turning the switch
onto the “LINE” position the 24 CH1, CH2, CH3 & CH 4 input can be connected to an audio source with high-level signal output. By turning these switches onto the MIC position, CH1, CH2, CH 3 &CH 4input can be connected to a dynamic microphone with low impedance. By turning the switch onto the “Phantom” position connects phantom supply n XLR of pin2 and pin3 of CH1, CH2, CH 3 &CH 4 necessary to operate condenser microphone which require this type of external supply. It is recommended to use this switch with the general volume set on minimum. -
Line Out Bal/Unbal
These terminals can be connected to other equipments, such as amplifier, recorder, etc. -
DC Power Supply
SPA-4 pre-amplifier can also operate using 24V DC power supply. When both the AC and DC source is connected, is shall operate using AC main whereas the DC supply shall be only consumed whenever the former fails.
INSTALLATION
INSTALLATION NOTES
At all times, the amplifier has to be operated under appropriate
conditions. This includes that the operation location provided sufficient
ventilation and the device is not exposed to direct sunlight or direct
radiation or reflection from any heat source. Installing the loudspeaker
systems choose a location that gets not affected by extreme and /or constant
vibration or other mechanical oscillation. Also make sure that the speakers
are installed at locations that are free from dust and /or moisture.
CAUTION
We strongly recommend that you leave the connection of the appliance to the
qualified and experienced service technician who specialises in connecting
electrical and electronic equipment. Do not take the risk of Electro-shock
hazard. To reduce the risk of Electro-shock, all connections have to be
accomplished before it is permissible to connect the amplifier the main
supply, before connecting the appliance to the mains supply, once again make
certain that all connections are carried out correctly and that no short-
circuit exist. The overall sound reinforcement installation has to be in
accordance to the laws, regulations, standards, and guidelines that are
relevant and applicable in the country where the equipment is going to be
operated.
AC POWER SUPPLY CAUTION
Before using the amplifier for the first time, make sure that the
appliance’s voltage is in accordance to your mains supply. Connect the
amplifier only to grounded mains outlets. Connecting the amplifier to the
mains supply (115/230Vac) has to be accomplished by inserting the supplied
mains cord into the corresponding docket.
CONNECTION DESCRIPTION
TROUBLESHOOTING
| Symptom | Likely Cause | What to do |
|---|---|---|
| No sound | Amplifier not connected | Verify that speaker is connected and that |
the circuit is on
Power not switched on| Switch on power and verify that power Led is on
No sound, amplifier is connected| Amplifier power cable is faulty or
improperly connected.| *Re-seat the power cable at both ends;
*Substitute a known-good power cable
Blown fuse| *Check fuse & replace with same type “spare fuse in holder”
No sound
Speaker comes on
| Signal source (mixer, Amp instrument) is not sending| *Check if the signal LED indicators are lit on
*Verify that the tape or CD is playing;
*Use headphones to verify that the instrument is actually sending an audio signal
Faulty cables & connections| *Disconnect and re-seat signal cables;
*Replace the suspected cable with a known-good cable
No sound with microphone connected to MIC / LINE input| Microphone requires phantom power| The EON does not supply phantom power. Switch to a dynamic microphone, use a battery powered microphone (if possible), use an external phantom power supply for condenser type
microphones.
Signal sounds distorted and very loud, LIMIT light is lit most of the time| Excessive input signal, trying to exceed the capabilities of the speakers| *Reduce the output level of the source;
*Turn down the level controls on the speaker;
*Use additional EON speakers
Lots of hiss in sound, mixer controls are at very low settings.| Improper gain adjustment or settings| *Make sure that the MIC / LINE switch is in the LINE(disengaged) position;
*Reduce the level settings at speaker, Review the Owner’s Manual for your mixer and adjust controls as needed;
*Input sensitivity(gain);
*Channel faders;
*Master faders;
Hum or Buzz| Improper A/Cgounding, ground loops| *”lift” audio ground by using XLR/F to XLR/M adapter on one end
*Re-route audio cables away from AC power and lighting cables.
Excessively long unbalanced cable run| *Use the balanced outputs(if available)of your mixer or source equipment to drive your EON speakers.
*Use the “DI”(direct injection) box to convert unbalanced equipment output to a balanced output.
Improper system gain settings| Reduce the INPUT level controls and increase the output level of your source devices.
Speakers feedback and howl when the microphone volume is turned up
| Microphones are pointed into the speakers| Move the speakers so they do not
point at the microphone’s pickup pattern.
Incorrect Equalizer settings| Locate the feedback frequency and reduce it
using the mixer EQ or an external equalizer.
Excessive gain| Reduce the gain at the mixer and move the microphone closer to
the sound source.
SEIKAKU TECHNICAL GROUP LIMITED
NO.I LANE 17, SEC.2, HAN SHI WEST ROAD, TAICHUNG 40151, TAIWAN
tel: 886-4-22313737 – fax: 886-4-22346757
www.show-pa.com
sekaku@sekaku.com
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