Selling a pair of Vandersteen 100 K X-2 high pass filters. I used this pair with a tube amp that had an input impedance of 200K ohms.
Inserted at the main input of the power amp, they will roll off the signal at a gentle first order slope (6db/octave). When integrating a subwoofer into a two-channel system, high passing the mains results in an enormous improvement. Barry Ober, one of the chief technical advisers at JL Audio, speaks to this in one of his white papers (
http://www.soundoctor.com/whitepapers/subs.htm). It's a great read on integrating a subwoofer into a two-channel system. Below is an excerpt regarding why high passing your mains is a good idea:
“Since you are now NOT putting in 20 Hz - 80 Hz into the mains you are not using up the available LF cone movement with bass, so the LF cone in your mains is able to play its higher frequencies (up to IT'S crossover point) much more cleanly. You get an apparent 6dB or more dynamic range. You can play your system LOUDER, and also with less compression distortion in the LF driver.
“Since you are not putting bass into that same driver you are not Doppler modulating everything between 80 and 600, or whatever the next crossover point is. This means cleaner mids by far.
“You are not sucking current out of your main power amp at low frequencies, so there is more current reserve to play those highs louder...”
These are in perfect condition and cost $120 new. Asking $75, including shipping and PayPal fees. Ships from 98332.
