[Don_S]

http://www.pureaudioproject.com/pap-c1-custom-active-analog-crossover-open-baffle/

From the PureAudioProject website.

"Based on the design of the legendary B5 crossover, the JFet based crossover circuits allow smooth and continuous -12db low and high pass filtering, between 100hz to 550hz. In addition, the PAP-C1 features an adjustable low-bass boost and high-mid shaving options."

XO will probably be at the California Audio Show. https://caaudioshow.com/2017-list-of-companies
I think it might also work for bi-amping any speaker or maybe the B5 would be better. 

[Chris Adams]

I just purchased one for my Trio15 Voxativ. I'll be using two Vinnie Rossi VR120s for amps.

[Don_S]

I just purchased one for my Trio15 Voxativ. I'll be using two Vinnie Rossi VR120s for amps.

Chris, do you already have a Trio15 Voxativ that you are using with another XO and single stereo amp?  I am curious what you think of the change.

[nicoch]

I just purchased one for my Trio15 Voxativ. I'll be using two Vinnie Rossi VR120s for amps.

the voxativ need a good triode or ss class A amp ....

[lowtech]

Fyi.  This is old news, but NP has pledged to offer the boards for this project to the DIY market.  He's also designed a JFET circuit to approximate the LXmini transfer functions.  http://www.linkwitzlab.com/LXmini/ASP.htm

[Chris Adams]

Chris, do you already have a Trio15 Voxativ that you are using with another XO and single stereo amp?  I am curious what you think of the change.

Yes, I do. I'm using a diy crossover and Vinnie Rossi LIO. It will be interesting to hear the difference.

[Chris Adams]

Fyi.  This is old news, but NP has pledged to offer the boards for this project to the DIY market.  He's also designed a JFET circuit to approximate the LXmini transfer functions.  http://www.linkwitzlab.com/LXmini/ASP.htm

I couldn't wait.

[poseidonsvoice]

Looking forward to your comparison posts Chris. In fact, I am a little surprised that there is a market for this given the multitude of very flexible digital DSP XO's available now (along with DIY mods). But I bet part of the impetus was because of Pass' notoriety as well as the allergy that some audiophiles have for ADC and DAC conversions. Nevertheless, I have great respect for Pass' design work.

Best,
Anand.

[Davey]

It's kind of like re-inventing the wheel.    This type of FET-based active crossover was concepted and implemented decades ago by various folks.  Certainly nothing as fancy ($$$) as these efforts from First Watt though.  This is basic second-order Sallen-Key filter circuits with a shelving filter option.

A comparison to a conventional (speaker-level) crossover with expensive components is just silly though.  Apples and oranges.

Dave.

[brj]

In fact, I am a little surprised that there is a market for this given the multitude of very flexible digital DSP XO's available now (along with DIY mods). But I bet part of the impetus was because of Pass' notoriety as well as the allergy that some audiophiles have for ADC and DAC conversions.

Or, alternatively, the need for multi-channel DACs.

My use of a passive line-level analog crossover lets me use a standard 2-channel DAC and pre-amp after my source, which was very much part of the design trade in building up my active system.  I wanted that level of choice.

Coincidentally, my passive analog line-level crossover is also Nelson Pass designed... an XVR-1.  As I'm also a fan of Nelson's work, I'd definitely consider a B5 or well implemented derivation if my system was single ended.  (Actually, a B4 or similar, given that my speakers are sealed.)

(I do toy with the idea of someday replacing the XVR-1 with a discrete, hard-wired differential crossover, but I have weaker links in my system than the XVR-1 just now, no matter how much that challenge intrigues me.  I should note that I perform the required driver EQ within my source, however, via HQPlayer's abilities to convolve an impulse response filter with the raw music bit-stream.  The XVR-1 handles only crossover and gain leveling.)

[poseidonsvoice]

Or, alternatively, the need for multi-channel DACs.

My use of a passive line-level analog crossover lets me use a standard 2-channel DAC and pre-amp after my source, which was very much part of the design trade in building up my active system.  I wanted that level of choice.

Coincidentally, my passive analog line-level crossover is also Nelson Pass designed... an XVR-1.  As I'm also a fan of Nelson's work, I'd definitely consider a B5 or well implemented derivation if my system was single ended.  (Actually, a B4 or similar, given that my speakers are sealed.)

(I do toy with the idea of someday replacing the XVR-1 with a discrete, hard-wired differential crossover, but I have weaker links in my system than the XVR-1 just now, no matter how much that challenge intrigues me.  I should note that I perform the required driver EQ within my source, however, via HQPlayer's abilities to convolve an impulse response filter with the raw music bit-stream.  The XVR-1 handles only crossover and gain leveling.)

Very impressive BRJ. Your system is definitely on the purist of the purists while retaining the advantages of active crossovers without the use of "excessive" ADC to DAC conversions 

Some day I need to listen to that setup given that I know the speakers well...

Best,
Anand.

[brj]

Very impressive BRJ. Your system is definitely on the purist of the purists while retaining the advantages of active crossovers without the use of "excessive" ADC to DAC conversions 

Thanks, Anand!  I like it, though it does come at the cost of a terrible number of cables... (Enough that I keep eyeballing the upcoming LIO crossover and DAC 2.0 modules in combination with the existing DHT pre-amp module - 3 components merged down into 1 box!)

Some day I need to listen to that setup given that I know the speakers well...

And you'd be absolutely welcome!  Just give me a chance to get my subwoofer swarm figured out first!

[poseidonsvoice]

I read with great enthusiasm Siegfried's latest aural discoveries, particularly his endorsement of NCORE modules (which we've known all along are great), but also that he found a configuration to make his ASP.4 to sound as good as the MiniDSP that used to reside in his system. It's funny how we all have some preconceptions and if these demons are not dealt with it will bother us forever (even the most grounded engineers!). Such was the case here:

http://linkwitzlab.com/my_setup2.htm#Why

And now I'm sure he'll have a sizeable camp of Linkwitz devotees who will drop their MiniDSP's like a bad habit and solder together the ASP.4 and implement it in the configuration he suggested in the end. But at least it's a well engineered solution, devoid of floobydust 

Audiophiles are fickle beings! But I sure do enjoy the ride! Thanks SL & NP.

Best,
Anand.

[Davey]

The two processors are identical.....conceptually.  Same transfer functions in both cases.
Audiophiles are fickle, yes, but there's a certain amount of irrationality that exists that's difficult to understand.  There's a difference between pro-analog and anti-digital.  Some audiophiles look in the mirror and they can rationalize the difference between those two. 

The reason I sent the original LX521 DSP prototype to Linkwitz to evaluate years back was not for absolute performance reasons, but rather to provide an alternative to the expense and difficulty of construction of the ASP.  Those reasons still exist.

Dave.

[poseidonsvoice]

Dave,

I will agree that you are more pragmatic than most! I am definitely not as pragmatic but I try and I think I've improved over the years.

Thanks for the therapy 

Best,
Anand.

[nicoch]

Well with Nelson jfet we can use tube or SS class A design and vinyl at the best we can do  in perfect line with the PureAudioProject  spirit

[Davey]

And right on cue, a perfect example of the irrationality. 
It's about the "spirit", I guess. 

Dave.

[nicoch]

sorry for  you good fullrange don't need a dsp  only a DTH ,
 that simple jfet xo  are only an utility  you can do with just a cap ...
pureaudio  is a passive serial xo system

[poseidonsvoice]

And right on cue, a perfect example of the irrationality. 
It's about the "spirit", I guess. 

Dave.

Don't you love it? The spirit of irrationality 

Best,
Anand.

[Don_S]

Don't you love it? The spirit of irrationality 

Best,
Anand.

Yes, It would be irrational not to.