Help finding a subwoofer

 how the input of a subwoofer is able to deal with signals from all amps in a high level input

The sub high level input is high impedance, so only uses voltage and very little current from the power amp. Level control adjusts.

A hundred-fold increase in power is only a tenfold increase in voltage and easily handled with a high resistance input potentiometer. How inaudible the additional wire and circuitry is depends on the power amp, cables and listener.

alanpiga, I'm sure I'm missing something regarding your sub requirements.

I see Cain & Cain offers a reasonably priced sub that seems tailored to their speakers when using a capable amplifier?

Your preamplifier appears to have an extra set of low line level RCA outputs? Are you currently using those outputs for something else?  

Thank you for your post. That Cain and Cain sub offering is years gone. Sadly Mr Terry Cain passed away years ago. Yes, that is a “lovely”. Open if one became available. Or two!!! Thanks again Bayle was the subs model name I thick.

By the way, I would not mind at all having a passive subwoofer with a separate component amlifier. From what I have seen online, I think that 500 box us can buy you a good one with DSP, ……. I am not sure a remote, so if anyone would like to contribute their thought on the idea and specific components and passive subs that would be great.

Thanks ieales for your educating post.