Ever tried putting a cap inline with RCA for XOVER

Hi There, I am trying to cross over my speakers on the cheap.

Anyone ever tried putting a cap inline with an RCA input on a amp to act as a passive High Pass Filter? I am trying to cross over my Wilson Cubs at about 70-80HZ.

My amplifier is a Mark Levinson No. 332 for Reference.

My goal is to build an adapter (Female to male RCA) with a capacitor in there to act as a passive crossover. I know this can be achieved on the interior of an amp but this amp is about as much of a cream puff as youll ever find, Im doing nothing to her (She got completely recapped and upgraded with better parts all around in 09 so shes good for a good long while now)

If that doesnt work how about a good DIY design? Should I go active? I am trying to go not too expensive and potentially avoid another box in my system, but I dont want to degrade my signal greatly, however I do believe a little signal loss would be an ok trade off for less woofer excursion

Which is better, Woofers working hard with more signal or.. working less but a tiny bit less signal?

Oh I play my music loud and listen to electronic music, acoustic is not much of an issue, White Zombie made me realize I was within 75% of the excursion limits at mid volume, I want to be able to play these guys loud and cant hit the high 90DB to 100 or so DB like I want, I am probably chickening out at 90 or so if that.


Yes Systembuilder, as 4est stated, it is done frequently. It's a great way to eliminate the need for extra ICs and keep the signal into the main speakers as "pure" as possible rather than running the entire signal through a crossover system first.

All you need to know is the input impedance (resistance) of the amplifier and your desired HP Filter frequency and you can calculate the capacitor value:

C = 1 / (2 * pi * F * R)
Be mindful of the units when using the equation Jafox supplied. If frequency is in Hertz, and input impedance (R) is in ohms, C will be in farads (and the answer will be a tiny fraction of a farad). Move the decimal point 6 places to the right (i.e., multiply by a million) to get microfarads (uf), or 12 places to the right to get picofarads (pf).

For example, 80Hz and 47,000 ohms works out to 0.000000042 farads = 0.042 uf = 42000 pf.

-- Al
Thank you again, This is going into my long term notes. I lucked out and forgot I had a Velodyne SMS-1 Lying around so I am using that as a crossover for now.

But I really needed to know how to do this.

Thanks a million yall
I second the Harrison Labs FMOD passive x-overs from Parts Express. I've used them successfully in the past to bi-amnp my party system.


Yep, you can do this, but what will you do about the resulting phase shift?