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Suggestions for a passive line-level high-pass crossover?

Looking for suggestions on a passive line-level RCA high-pass crossover that I can insert between my preamp’s outputs and the amplifier that is driving the mids and highs of my bi-amped speakers. I don’t need anything fancy or overly complex, but I am looking for audiophile-grade circuitry that will have the least sonic signature.

 

Specifically, I need it to be a 100 Hz high-pass crossover point, with a slope at of at least 12 db per octave. Doesn’t need to have a level control, adjustable settings, etc. Simple, but high-performance parts and sound.

 

Any suggestions?

 

Thanks gang!

 


128x128mhwalker
bdp24's avatar
bdp24
9,412 posts
 

A passive high-pass filter is commonly accomplished via the insertion of a single capacitor on the input jacks of the main speaker’s power amp, the value of the capacitor determined by: 1- The desired x/o frequency; 2- The input impedance of the power amp. However, this method creates only a 1st order, 6dB/octave filter. For a 12dB/octave (2nd order) x/o, filtering is best accomplished via an active x/o.

A reasonably priced but also high-quality active x/o is the First Watt B4 (all discrete circuitry---no IC’s, no Opamps), which provides all the filters one should need: 1st, 2nd, 3rd, 4th order (6, 12, 18, 24 dB/octave) slopes from 20Hz to 3200Hz, in 25Hz increments. The B4 retails for $1500, but Reno Hi-Fi (a main retailer of First Watt products) sells it at a discounted price. It is about to be discontinued, so get one while you can!

yogiboy's avatar
yogiboy
5,464 posts
 
How about this?
http://www.hsuresearch.com/products/high-pass-filter.html
Or this?
https://www.parts-express.com/harrison-labs-fmod-inline-crossover-pair-100-hz-high-pass-rca--266-274
rodman99999
5,981 posts
 
The following manual(for the Dahlquist DQ-LP1) contains a formula for, and a chart of, the values(capacitors and if needed, resistors) that will give you your desired crossover point(BUT- 1st order), based on the input impedance of your mid/high amp. Keep in mind that greater than a 1st order(6dB) slope will cause greater than 90 degrees of phase shift, in your mid/high drivers. For instance, with a 2nd order(12 dB/oct) filter, you may find the best sound with either the mid/high or bass driver connected out of phase, unless they were already designed for a higher order slope. I had always used polypropylene film and Vishay metal film resistors(when required), to achieve the absolute minimum signal distortion/degradation. I have installed such filters inside amps, at the RCA terminals, to eliminate the need for additional connectors and cables. See, "technical" on page 4: (https://sites.google.com/site/mpbarney/home/dahlquist-dq-lp1)  Don't know if you can use any of that, but- what the hell.......  =8^)
sfall
346 posts
 
Do a vertical biamp instead. You won't need the xover.
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