High to line adapter circuit

[ALPUY]

Hi. I need to provide a circuit or diagram necessary to connect an amplifier to its line input from the speaker output of another amplifier.
In case I was unclear. I have a Marantz PM6006 amplifier connected to B&W DM602 speakers.
I want to connect an amplified subwoofer, but it has only line input (RCA), not high input.
Since the Marantz does not have a preamplifier or subwoofer output, I need some high to line adapter circuit.
Regards.

 

[wrankin]

One solution would be to use a simple voltage divider using two resistors or a resistor and a pot. Here's a gross diagram:

Vin -> R1 ---- R2 -- GND
           |
           |--> Vout

Vout = R2/(R1+R2) * Vin

First, figure out what gain reduction you need. Make R2 around 10k ohms or so and assign R1 accordingly (~100k would give your a 0.091 reduction, about -21dB). Use good resistors. 1/4-watt power rating should be more than sufficient.

If you want adjustability replace R2 with a 10k ohm potentiometer. Hook the center tap and one of the ends to ground, the other end to R1.

Others will likely have more better more complex solutions, but this will work.

-b

 

[nironiro]

Check Denon amplifiers and receivers, they have preamp out from speakers level, just with simple voltage divider, just as wrankin said.