Recommendations for electronic crossover.

phusis
Its all a matter of degree. Whether an active XO system using IC op amps sounds better than a passive system with the best Mundorf or other high end caps, inductors, and resistors may be arguable. 

But it makes no sense to me to place an EQ/XO having IC opamps between a discrete component preamp and discrete component power amps. I actually tried that with a Phonic i7600 op-amp DSP between my Parasound JC2 and two JC1s when trying too chase down a frequency balance issue (and it was good for that), but the sound quality through that Phonic unit did not sound as clean and detailed and the system with a passive XO and the Phonic removed. 

I am probably in the camp leaning toward an active system, but will not compromise in using IC op amps vs discrete class A circuitry. Every time I have made a comparison of products with IC op amps vs discrete, discrete always wins hands down. I think both Nelson Pass and John Curl would agree with me (along with Bryston). So I am in the process of designing and building an all discrete 4rth order Linkwitz Riley LP/HP XO system for the PAP Horn1 speakers. It will also have discrete op-amp gyrators for a parametric EQ function. Expensive, time consuming, and rather large, but I think it will be worth it.

Well, I finally finished my discrete Class A XO project. I used my own design discrete op amps, based on an early Spectral design modified with Nelson Pass inspired JFet output stages (instead of MOSFET stages as originally used by Spectral). I am using 4rth order Linkwitz Riley filters for both HP and LP filters and the drivers integrate smoothly

Took out the gyrators as I really did not need parametric EQ with the Voxative drivers (switched from the Horn).  

System is now sounding better than it's ever sounded. So that confirms that the active XO system has merit in principle, and the class A discrete designs in practice.

@dhl93449 --

... So that confirms that the active XO system has merit in principle, and the class A discrete designs in practice.

Thanks for the follow-up, and good to learn that your active XO project has come through successfully.

From my chair though it still goes with absolute conviction: less will do, even in excellent fashion. A pro digital cross-over from Xilica that friends of mine and I are using in our respective set-ups is a rock steady performer that has sonically lifted passive speaker systems (in theirs and others set-ups; my own speakers have been sans passive XO’s to begin with) into more transparent, tonally authentic and dynamic sounding dittos. Simply better in every perceivable aspect, period.

I believe it’s an unfortunate, even dead wrong message to put there saying that only the über-best of the best active XO’s will do compared to passive iterations, especially compared to a limited range of digital XO alternatives and not least with reference to:

... it makes no sense to me to place an EQ/XO having IC opamps between a discrete component preamp and discrete component power amps.

Whether it makes sense or not is a matter decided by the ears, not theory, but of course: if what your ears tell you is in favor of a passive configuration - in a specific, singular component context, that is - then that’s what it is to you in that particular scenario.

Few have actually tested their own or to them well-known passive speakers as converted-into-active dittos, with the potential experience of actives coming predominantly from all-in-one packages that leave little insight to be exposed other than the choices made with those particular designs, rather than what merits conclusive or more fully formed statements into passive vs. actives.

Active configurations hold great potential, also as a solution of separate components with all that entails into the free choice of amps, cables, DAC’s and digital XO’s at reasonable prices - somewhat cheaper even, despite the more amp channels needed, than a passive set-up.

phusis

" Whether it makes sense or not is a matter decided by the ears, not theory, but of course: if what your ears tell you is in favor of a passive configuration - in a specific, singular component context, that is - then that’s what it is to you in that particular scenario."

Yes but the comparison is not passive vs active w Class A discrete, but active Class A discrete vs digital + IC opamps. No doubt digital processing has the flexibility to provide complex transfer functions, frequency responses (and time delays) that no discrete component system could duplicate, but from a pure sonic purity perspective, they will never match that of discrete Class A designs, assuming you don't need the frequency response complexity. With the Voxativ and PAP bass drivers, their response is reasonably flat enough that just a simple 4rth order HP/LP XO will do, assuming the XO point is well chosen. 

Why are there very little discrete Class A XO products available today?
They are expensive to build, large in size, and use components (ie the transistors) that are getting harder and harder to find, as well as expensive. A single matched pair JFet from Linear Systems now cost more than most IC opamps. The Toshiba parts are long out of production and only available from manufacturers (like Pass Labs) who horded these parts many years ago.  But the fact that companies like Pass Labs, Bryston and Parasound still build their top of the line products with discrete components still attests to the sonic superiority of these designs. If a lower cost IC opamp 

really provided sonic equivalence, all discrete designs would be gone in a heartbeat.