For those interested in crossovers, the XVR1 crossover is now listed on the Pass Labs website. Go to Products and scroll down nearly to the bottom; it's listed under the preamps. No data yet, but there's a description and pictures of the unit, both inside and out.
The first run of XVR's is in production and will ship at the
end of the month. Lots of information will be out soon,
as I am having to essentially write a book for the owner's
manual, and we'll be putting it up on the site.
I've been working on this piece for almost 3 years, and
I believe the results are pretty spectacular.
With great anticipation, I have been awaiting the High/Low Pass
electronic crossover. This crossover is talked about on the Pass DIY site. Will the high/low Pass electronic crossover be similar to the new Pass XVR?
Anybody know when the High/Low Pass is going to debut on the Pass DIY site?
The piece looks beautiful! It will be nice to have a decent crossover available...
I've been a lurker for quite some time and this is my first post...
Thanks to Nelson for his generosity and patience with those of us out there attempting to tackle aspects of this stuff ourselves... Thanks for never losing the love of the hobby!
I currently own Threshold equipment and now am eyeing the X-1 as a replacement preamp for my next step... It will take a while to get there but it will be well worth the wait...
Thanks also to the other members for their constant help and advice!!
I have a question regarding the circuit design of this unit. On the Pass site it mentions "The discrete circuitry for every stage consists of matched low noise JFETs driving bipolar output transistors, all biased single-ended with constant current sources." Why the departure from Mosfets in the output stage?
The manual for the crossover has been posted on the Pass Labs site.
They'll be publishing a <i>Crossovers For Dummies</i> book in the near future for those who are unable to cope with the psychic trauma induced by having to think for themselves...
The poor darlings will be forced to choose between Low, Medium, and High Q (the manual doesn't specify, but I'm guessing .5, .707, and 1), in addition to crossover points (a bakers' dozen, not counting multipliers), slopes (1st, 2nd, 3rd, and 4th order), and levels. The only thing it doesn't have is infinitely variable phase, but that doesn't implement well in the real world short of manipulating things in the digital domain (yuk).
Interesting reading. If you keep your wits about you, certain deductions can be made about the circuit.
Looks like a fun toy.
I just downloaded and read the XVR1 owners manual from www.passlabs.com. This device absolutely rules! I've never had so much fun reading an owner's manual. Looking forward to the DIY version. I was never all that enthusiastic about bi-amping until now. That means I'll need to build 2 Penultimate Zens. Really cool work NP!
Incidentally, how's that discrete mosfet version of ENIAC coming along?
20,000! Wow. There's a great article in this month's Invention and Technology about Steve Wozniak. In it he describes a 10bit adder he built when he was young from all discrete components. I thought of your project, but 20,000! That's major. He also talks about how they used to send schematic packs out with their computers with code listings, etc. because people actually wanted to know how the things worked. That was the golden age of computing. I can still remember writing games in 8K of RAM! Best of Luck.
Given any thought to designing a discrete equalizer? I never liked those either, but if you designed one, I bet it would change a few minds. And just think of all the knobs to adjust!
I read through XVR1 manual. There are 2 inputs (L+R) and 4 outputs (2 each for high as well as low frequencies). The manual does not describe any way for using this with 2 satellites and one subwoofer. Is it possible?
This is not the intended use for the XVR1 but it certainly is possible. Having 39 frequency steps per pole, one to four poles per filter, and variable "Q" for each pair of poles is a bit overkill for subwoofers.
You can sum the outputs and drive a single subwoofer.... or not sum the outputs and drive dual voice coils on a single subwoofer.
Actually though, I find that degree of adjustability most
useful for subwoofers, being that they usually need some
I occasionally put 1 or 2 poles down at 22 Hz or so to really
flatten out the response and then additional poles to get
rid of the woofer above its usable frequency. It may only
result in two octaves of response, but it's flat.