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
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^)

Bi-amping vertically (rather than horizontally) does not negate the need for a x/o to accomplish. Neither of the two amps in a bi-amped system knows whether it is being used vertically or horizontally (other than in the sense of how the amp and speaker interact with each other), and that consideration has nothing to do with the x/o itself.

Using one amp for both the low-pass and high-pass on the same speaker (vertical bi-amp) has it’s advantages, and using one amp instead for either the low-pass or high-pass on both speakers (horizontal) has it’s. Using a solid state amp for the low-pass (bass) signal on both speakers, and a tube amp for the high-pass (mids and highs) on both, works great with many speakers.

" Bi-amping vertically (rather than horizontally) does not negate the need for a x/o to accomplish. "

Unless you have some really odd equipment, that's not true. There's no xovers on my vertical biamp system, or any other one I know of.

" Neither of the two amps in a bi-amped system knows whether it is being used vertically or horizontally (other than in the sense of how the amp and speaker interact with each other), and that consideration has nothing to do with the x/o itself. "

The amp may not know, but you need to.

" Using a solid state amp for the low-pass (bass) signal on both speakers, and a tube amp for the high-pass (mids and highs) on both, works great with many speakers."

You'll get sound, but its usually an unbalanced train wreck. When you put an active xover in the system, you can get the levels right, but now you have to listen to one amp on the mids and highs, and another on the lows. Who would want that? Do it right the first time and be done with it. Also, don't forget that the active xo will have a big impact on SQ. It will negate a good portion of what your source, cables and preamp are doing.

The lucky owners of Vandersteen 7’s, for one. That speaker comes with a powered (via a solid state amp) subwoofer, and many 7 owners use a tube power amp for the upper drivers. People have done that successfully for decades, with speakers like the Infinity RS-1b, for one.

sfall, if you don’t have an external x/o splitting the signal into two or three sub-signals, you are sending a full-range signal to all the drivers---not a good idea! Are you sure you’re not just using a pair of stereo amps to in effect bi-wire your speakers? Bi-amping absolutely requires an external x/o, whether passive, active, or a combination of both. If an external x/o (external in the sense of not inside the speaker. A passive filter can be inside the power amp, on it’s input jacks) is not present, bi-amping is not, by definition, being accomplished. The outboard x/o replaces the speaker's internal one, splitting the full-range signal from the pre-amp at line-level and feeding the divided signal to one amp for the low-pass signal (bass), and one for the high-pass (mids and highs, typically), rather than at speaker-level (after the power amp---inside the speaker). Each amp then is fed only the frequencies intended for the driver(s) it powers. That’s the whole purpose of bi-amping!

Bi-amping with an active x/o (or passive) can be done vertically with a pair of identical amps if one so desires.