Quad 44 Sub woofer output

[Warlord_1011]

I have a Quad 44 and Quad 405-2 stereo setup, however i recently obtained a B&W ASW650 Sub woofer(22kOhm Input Impedance). Now reading the technical spec for the Quad 405-2, and it says the amplifier loads the input with 20 kOhm in parallel to a 220pF capacitor. Now if i wired a Lowpass RC Filter (20Kohm & 44nF Capacitor) parallel to the amplifier to provide an output signal for the Sub woofer with a crossover frequency of 180 Hz would it effect the performance of the Quad 405-2?

Would using two lowpass filters (one for each channel) and then merging them into a mono input for the Sub woofer cause crosstalk?

**broken link removed**
By taylor102121

on the diagram i replaced the two 20K ohm resistors with 47Kohm to create a mono signal.

 

[Nigel Goodwin]

As it's an active sub, doesn't it alredy have the required low-pass filters fitted in it?.

 

[Warlord_1011]

Yea it does, I didn't think of that, but how should I wire the Subwoofer to the Quad? should i Use one of the 5V or 1.6V phono outputs, drop it down to a mono signal and then input that into the Subwoofer?

 

[Nigel Goodwin]

I would be inclined to simply tap off the speaker outputs with a couple of high value resistors, joined to a common resistor down to ground (making an attenuator) - no need to mess about in the preamp stages.

 

[Warlord_1011]

but if the signal needs to be line level, then why dont i use the 1.6 Volt Stereo pre out and drop it down to a mono signal for the sub woofer?

 

[Nigel Goodwin]

but if the signal needs to be line level, then why dont i use the 1.6 Volt Stereo pre out and drop it down to a mono signal for the sub woofer?

You could, but there's less (none at all) chance of crosstalk between channels using the speaker outputs.