Which Pass amps scale?

[Fritz]

I have a feeling that when my ZenV4 is done I will also say its worth it. The reason I want a scalable amp is because Im considering building the Linkwitz Orion Speaker. It uses four channels per stereo side and the active crossover circuitry requires matching gain and sensitivity. The bass channels would probably do well with more than 50 watts while the others could have 50 or less.
I realize 1000-1500w wont imediately cook me out of the room but my 1200 watt room heater definitely cooks me out of the bedroom in about 4 hours on a cold night. With 100 plus summers its something to consider. I guess it would probably take about 2500W to get that heat back out of the room. But Im thinking the amps might look nice in the unused fireplace and all the heat could go straight up the chimney.
My Chevy Suburban gets 9 MPG (for sale) at 65 MPH I think it takes about 20 HP to do this and thats about 15000 watts continuous by electric standards. So a one hour trip is 15 kilowatt hours and costs about 9 dollars in gas( I think thats about 10% thermal efficiency). The same 15 KWHs in the amp would cost about 2 dollars and would take me several days. Thats fairly cheap entertainment if I can stay comfortable in the room. Figure half of the year its doing what I want by heating the room and that doubles its efficiency!
Im very anxious to hear the class A and Id imagine at that point the decision will be based on pleasure as are most decisions in our not so green world.
I think if I bias down 3 of 4 pair I could keep it to 1KW total.

[jh6you]

I need 6 channels in the 30-50 watt range and 2 in the 60-100 watt range. Does anybody know of Pass circuits that scale…?

You know cowanrg…?
IMHO, he could help you best.



PS
Does IMHO stand for in my honest opinion?
I used it for in my honest opinion.

[Fritz]

Cowrang?

No whats that?

[Peter Daniel]

I guess he meant that:

cowanrg
diyAudio Elder

Registered: Apr 2002
Location: Boulder, CO

[GRollins]

Here's how I see it.
Really good class A solid state is roughly equivalent to better-than-average class AB tube in sound quality. There are a few really oddball solid state circuits that manage--in spite of their maculate origins--to sound pretty close to tubes. The old Electrocompaniet 50W (solid state) comes to mind as an example. Damned fine sounding amp. No, I never heard the Krell KMA/KSA50s on a system that I was familiar with (only on Martin Logan CLSs...yuk...that upper midrange glare was something I couldn't bear), so no opinion there. The Aleph 2s I've got here (homebrew, not production units) manage the same feat, albeit without imaging quite as well as my ohmigod tube amps that I built a few years ago, and without <i>quite</i> the detail. That one's closer, though. (There's also an oddity in that the Aleph's image is offset about a foot behind my tube amps--I tossed this at Nelson and the consensus was that no one knows what goes on to make an image.)
I can't stand that Nelson's nipping at my heels on this. Changes are pending to the tube amps. Possibly a return to class A--something I tried for a while...loved...but wasn't willing to live with that little power (about 40W instead of 130W or so). But am I willing to buy new output transformers, etc. to build a bigger class A tube circuit? The jury is still out. Money don't grow on trees and it's been a rough year. We'll see what happens.
(An X tube amp? Sure...why not? My circuit's pretty much there anyway, even without knowing that I was getting "X-ness" at the time. Just one little change to tune it up a smidgen and incorporate a few things I've thought of in the interrim...)
Class A tube gear? Now that's something that solid state has yet to even approach. Can it be done?
Well...
Nelson?
He's about the only guy I know who can do it.

Grey

[hifi]

Btw,

Did you (Grollins) make a Tube based X preamp featuring ecc88 ? will you be presenting Schematic / layout anytime soon? if ever?

I think i read about it somewhere on the forum although i dont remeber where..


/micke

[GRollins]

Yep. 6922/6DJ8 and 6SN7 versions already pretty much done. I'm going to get the solid state versions together before I do a writeup. That, in turn, will be after I get some other stuff done. There's only one of me and (unlike, say, Nelson) no employees to help.
I've got enough ideas floating around for quite a few writeups, but I'm afraid to mention anything more than I already have, since I don't have the resources to bring them to fruition quickly and people get frustrated. Witness the fuss over whether Nelson should publish El Pipe-o, The Claw, a crossover (I've already got a slow-motion thread on that topic that I should update), or a monster amp first. And he's got help. (Not to mention more resources to draw upon.) I'm in the semi-final stages of building a pair of 11' transmission lines, but don't have any immediate plans to write it up--there are plenty of TL designs out there and Nelson's should be out soon.

Grey

[Variac]

I've always heard: In My Humble Opinion
To show you aren't the know it all type


And I suspect Nelson's "help" has the main job of trying to keep him focused on the commercial jobs

[jh6you]

… That was IMHO.
… Thanks.