High Pass Filter for Mains

Thanks for the inputs.

I think I'm going with the Marchand balanced passive filters with a 80hz cross. It's $200 more but fits my connectivity better. What I meant about "a single cap" is its a single connection for me. Inside it's full of components. He offers 30 day returns so I'll order the sub when it arrives and have 30 days to evaluate. 

I'm just surprised with all the niche audiophile products out there, only one guy makes these. It makes me wonder whether this is an unusual endeavor in audiophileland. I've seen some previous discussions but no real conclusions. I'll report back when I complete the experiment. 

I've had a Marchand for over 20 yrs.  I've had Phil Marchand check it.  He has always been accommodating for me.  He uses good attenuators which make a difference and put new op amps for mine.

The new company Sublime looks to be comparable.

I bought a 2-way electronic crossover from Phil Marchand last year.  It's built like a tank and sounds fantastic.  A very good friend is running the same Marchand crossover in his system, and it's been rock solid.

I’m pretty sure GR Research, you can google their website, makes passive hi-pass filters.  They design crossovers for speaker manufacturers.

They will use much higher components than anything discussed above and they are very reasonably priced.

A cheap hi-pass filter will seriously degrade your sound.

Want to point out that even if you do use an analog crossover, a DSP EQ on the sub is still beneficial.  I would say if you can leave your high pass for your main amp and let the DSP handle the low pass for the sub, and everything else you'll find much better flexibility and easier time integrating the sub with the room and the sub with your mains.