JL Audio HD900/5 owner manual Channel Control Sections, Input Sens. Controls

Page 10

The output of the amplifier decreases for a given input voltage when the “Input Range” switch is placed in the “High” position. The output increases with the switch in the “Low” position. While this may sound counter- intuitive, it is correct as described.

CHANNEL CONTROL SECTIONS

To the left of the “General Setup” section on the Control Panel of the amplifer are three sets of controls: one for the “Rear Channel Controls” one for the “Front Channel Controls” and

one for the “Subwoofer Channel Controls”.

In each of these sections you will find a rotary control labeled “Input Sens.” (Input Sensitivity). These controls are designed to match the input sensitivity of each channel section of the HD900/5 to the specific signal source that

is feeding the amplifier. These controls must be adjusted, with care, following the procedures outlined in this manual. Failure to make correct adjustments can result in weak output, excessive distortion and/or undesirable noise in the audio output of the amplifier!

Note: The Channel Control sections also house “High-Filter” or “Low-Pass Filter” and “Filter Freq.” controls. These are crossover filter controls and will be discussed in the next section of this manual. This section will explain the Input Controls only.

“Input Sens.” Controls

Once the appropriate “Input Voltage” range has been selected in the “General Setup” section of the amplifier, the “Input Sens.” controls are used to match the source unit’s output voltage to the input stage of each pair of amplifier channels

for maximum clean output. Rotating the control clockwise will result in higher sensitivity (louder for a given input voltage). Rotating the control counter-clockwise will result in lower sensitivity (quieter for a given input voltage). To properly set each pair of amplifier channels for maximum clean output, please refer to Appendix C (pages 18, 19) in this manual.

After using this procedure, you can then adjust the relative level of each channel pair by adjusting the input sensitivity downward on any of the channel sections, if they require attenuation to achieve the desired system balance.

Do not increase the “Input Sens.” setting for any amplifier or channel section in the system beyond the maximum level established during the procedure outlined in Appendix C (pages 18, 19). Doing so will result in audible distortion and possible speaker damage.

Be aware that all three “Input Sens.” adjustments will need to be made, regardless of how many input cables are feeding the amplifier. These controls will allow you to set the appropriate relative levels for the “Front” channels relative to the “Rear” channels and the “Sub” channel (and any other amplifier channels in the system).

CROSSOVER CONTROLS

Crossovers are groups of electronic filters designed to control the frequency ranges that each speaker in a system will be tasked with reproducing. Proper crossover setup is critical to sound quality and reliability.

The HD900/5 has three individually adjustable filter controls, one for the “Front” channels, one for the “Rear” channels and another for the “Sub” channel. The “Front” and “Rear” filters are high-pass filters (they attenuate low frequencies),

10 JL Audio - HD900/5 Owner’s Manual

Image 10
Contents Channel Class-D System Amplifier Protect Your Hearing Installation ApplicationsPlanning Your Installation Serial NumberYour JL Audio amplifier employs an Safety ConsiderationsCooling Efficiency Considerations Stupid Mistakes to AvoidProduct Description As we said, it’s very flexibleRun power wire from the battery location Typical Installation SequenceConnect the RCA input cables To the amplifier Fuse Requirements +12V Battery ConnectionPower Wire Requirements Ground ConnectionTurn-On Wire Amplifier Power Connector PlugLateral Mounting Feet HD900/5 has two mounting options to ease in installationStandard Mounting Security cover is secured by a singleInput Voltage Switch Input Mode SwitchCh. Input Mode Amplifier INPuTSChannel Control Sections Input Sens. ControlsFilter Freq. Hz Control Infrasonic Filter Subwoofer Ch. OnlyAfter proper adjustment of the HD900/5’s Bi-AmpLIFIED SYSTEMSMultiple phone cables REmote level control OptionalStandard telephone cable supplied with the HD-RLC Speaker OutputsSpeaker Connector Plugs Status LED / Protection Circuitry Servicing your JL Audio Amplifier JL Audio Technical SupportCrossover Filters Appendix a HD900/5 SpecificationsChassis Dimensions LxWxH Input SectionsFull-clockwise Appendix C Appendix B  Precise Frequency Selection ChartNecessary Equipment Channels at 3/4 source unit volume Nine-Step ProcedureIncrease the Input Sens. control until My amplifier doesn’t turn on My amplifier turns on, but there is no output INSTALLATION NOTES Page JL Audio, Inc Limited Warranty Amplifiers USAIf you need service on your JL Audio product International Warranties