Greetings:
As a labor of love I am trying to repair/rebuild a 100W(?) amplifier built into a subwoofer speaker. Unfortunately I cannot find a schematic for this "Paradigm Cinema Sub 0.2" subwoofer.
The subwoofer low level input is intended to be fed from a surround sound, JVC receiver equipped with a sub woofer output. This subwoofer output is internally fed from both left and right channels which are mixed together and then low pass filtered to pass only low frequency audio to the sub woofer output phono jack which resembles a line output.
This output appears to have a high source impedance as it would not drive headphones. I have had a chance to measure the level and source Z yet as receiver is at a different location. I didn't happen to have my scope with me when I had access. The amplifier output does work with another subwoofer from a different manufacture as long as the volume control gain on that woofer is set near max.
In my search to find specitication standards for low level subwoofer interfaces I ran across a sub woofer amplified speaker with a specified low level input level of 75 mV rms and input impedance of
50KOhm.I drew a schematic of the input circuitry of this amplifier by tracing the circuit board and have concluded the input Z is about
10K in this case. Considering the attenuation ratio from the alternate speaker inputs a line level input 2V ptp would match the level from 10 watts RMS across 8 Ohms on alternate speaker inputs.The sub woofer was manufactured by Paradigm and is a model "Cinima Sub 0.2". I wish for a schematic for the amplifier which is built from discrete components.
The receiver/amplifier is a JVC MODEL RX-6042 AUDIO VIDEO CONTROL RECIEVER.
Thanks in advance to anyone who can enlighten me on typical subwoofer low level interface operating levels and impedance or better still a place from which I can download a schematic for this amplifer.
Tom Alldread snipped-for-privacy@telus.net