User manual JL AUDIO 300-2

[. . . ] JL AUDIO 300/2 two-channel full-range amplifier o w n e r 's m a n u a l Thank you for purchasing a JL Audio amplifier for your automotive sound system. Your amplifier has been designed and manufactured to exacting standards in order to ensure years of musical enjoyment in your vehicle. For maximum performance and extended warranty coverage, we highly recommend that you have your new amplifier installed by an authorized JL Audio dealer. Your authorized dealer has the training, expertise and installation equipment to ensure optimum performance from this product. [. . . ] In the "x1" position, the range of the rotary control is 50 - 500 Hz (as marked). In the "x10" position, the range of the rotary control is 500 Hz - 5 kHz (5000 Hz). (Hz)" The filter frequency markings surrounding this rotary control are for reference purposes and are generally accurate to within 1/3 octave or better. If you would like to select the filter cutoff frequency with a higher level of precision, consult the chart in Appendix A (page 12) of this manual. PREAMP OUTPUT SECTION The 300/2 incorporates a flexible preamp output section, so that additional amplifiers can be added to the system. This pre-amp output can be configured three different ways using the switch labeled "Output Mode" in the "Preamp Output Section". 1) "Full-Range": The preamp output delivers the same signal that is connected to the 300/2's Amplifier Inputs. 2) "Low-Pass": The preamp output delivers the same signal that is connected to the 300/2's Amplifier Inputs with Low-Pass filtering applied to it at the "Filter Freq. " and "Filter Slope" selected in the "Amplifier Filter" section. This mode can be useful for feeding a subwoofer amplifier when the 300/2 is being used to drive the main speaker system. 3) "High-Pass": The preamp output delivers the same signal that is connected to the 300/2's Amplifier Inputs with High-Pass filtering applied to it at the "Filter Freq. " and "Filter Slope" selected in the "Amplifier Filter" section. This mode can be useful for feeding a second satellite amplifier when the 300/2 is being used to drive the main speaker system. NOTE: The signal level of the "Preamp Output" is affected by the setting of the "Input Voltage Range" switch of the amplifier. See the "Input Voltage Range" section (page 7) for details on "Input Voltage" settings. The preamp output level is not affected by the "Input Sens. " rotary control. SPEAKER OUTPUTS The 300/2 employs JL AUDIO's exclusive Regulated, Intelligent Power Supply (R. I. P. S. ) design. This sophisticated power supply allows the amplifier to produce its optimum power (300 watts) over a wide range of speaker impedances. Unlike conventional amplifiers that require a specific impedance to produce optimum power, the R. I. P. S. -equipped 300/2 gives you the freedom to use a variety of speaker configurations that achieve final impedances between 1. 5 ­ 4 nominal per channel (without sacrificing power output or sound quality). circuitry is entirely automatic and adjusts itself every time the amplifier is turned on according to the lowest impedance present at the speaker outputs . There are no user controls to configure. The system operates through multiple stages of impedance optimization, choosing the stage most appropriate to the actual impedance of the speakers you connect to it. !I M P O RTA N T If you connect a load higher than 4 nominal per channel in stereo mode (or 8 in bridged mode), power will drop by half with every doubling of impedance above 4 stereo / 8 mono. If you connect a load lower than 1. 5 nominal per channel in stereo mode (or 3 in bridged mode, the amplifier protection circuitry activates a "safe" mode which reduces amplifier power to protect the circuitry from failure (the yellow "Low " LED lights to indicate that this has happened). I M P O RTA N T Speaker loads below 1. 5 nominal per channel in stereo or 3 nominal in bridged mode are not recommended and may cause the amplifier output to distort excessively. 8 JL AUDIO 300/2 JL AUDIO 300/2 9 BRIDGING CONSIDERATIONS Bridging is the practice of combining the output of two amplifier channels to drive a single load. When bridged, each channel produces signals of equal magnitude, but opposite polarity. The combined output of the two channels provides twice the output voltage available from a single channel. The 300/2 has been designed for bridging of its channel pairs without the need for input inversion adaptors. To bridge a pair of channels, use the "Left +" and "Right ­" speaker connectors only (the "Left ­" and "Right +" remain unused). When bridged, the 300/2 will deliver optimum power into a 3 - 8 load. Operating a bridged 300/2 into a load lower than 3 is not recommended. Because a bridged pair of channels requires that both channels receive input, you need to connect both left and right RCA inputs to the source unit. Connection of only one RCA input will result in reduced power output, increased distortion and can cause the amplifier to overheat. Instead, use a "Y-Adaptor" to split the mono signal into both left and right RCA inputs. If you are bridging a pair of channels and use a stereo input, the only information that will reach the amplifier stage is the common-phase portion of the signal. This may be useful for passively deriving a center-channel signal, but is not going to give you a defined left or right channel. [. . . ] of Inputs: One Stereo Pair Input Type: Differential-balanced with RCA jack inputs Input Range: Switchable from 200mV - 2V RMS to 800mV - 8V RMS AMPLIFIER SECTION: Amplifier Topology: Class AB with patented Absolute SymmetryTM dual N-Channel MOSFET output design Power Supply: Independent, pulse width modulationregulated switching power supply with multistage impedance optimizing circuitry. Rated Power (Stereo): 150W RMS x 2 @ 1. 5-4 (11V - 14. 5V) Rated Power (Bridged): 300W RMS x 1 @ 3-8 (11V - 14. 5V) THD at Rated Power: <0. 03% @ 4 per channel (20 Hz-20 kHz) Signal to Noise Ratio: >108. 5 dB referred to rated power (A-weighted, 20 Hz-20 kHz noise bandwidth) Frequency Response: 5 Hz - 30 kHz (+0, -1dB) Damping Factor: >200 @ 4 per ch. / 50 Hz Slew Rate: ± 25V/µs AMPLIFIER FILTER: Filter Type: State-variable, 12 dB/octave Butterworth or 24 dB/octave Linkwitz-Riley Low-Pass or High-Pass with continuously variable cutoff frequency from 50 - 500 Hz, switchable to a range of 500 - 5000 Hz, via x10 switch. PREAMP OUTPUT: 2-Channel, switch-selectable as pass-through type, tracking High-Pass, or tracking Low-Pass linked to Amplifier Filter. [. . . ]