X100 backengineered here

[mefinnis]

Grey,

Relax. I actually wrote to Nelson BEFORE I even contemplated building my Aleph, expressing surprise and concern that he had "left himself open to be ripped-off".

The reply was, "I expected this, this is why I published the service manuals ......"

Now .... you gotta admire that mate !!!

mark

[Petter]

I had initially planned to do this, but I have gone cold on high-dissipation amps (no pun intended). Anyway, I suspect a pure Aleph will sound better than a hybrid anyway since the Aleph circuit is much simpler, and the fundamentally balanced topology does not lend itself directly to a pure SE non-bridged design.

So what I propose you do is consider increasing the quiescent current for the X so much that you have pure class A. Of course, you don't get the Aleph efficiency if you are running 100% class A, but then again, it can be argued that positive feedback isn't really class A after all ...

[GRollins]

Mark,
I was referring to the X circuit, not the Aleph. I assumed that Nelson was giving implicit permission when he published the full Aleph circuits. Ya can't expect to dangle a carrot such as that out in front and not expect the mules to jump! The X, however, is just beginning its product life and is Nelson's bread and butter at this time. From what I know of such things, right about now he's in transition between the early adopters and the mainstream buyers. He still anticipates selling many more units. Having full, presumably semi-accurate schematics for the X series floating about now would be equivalent to having had the Aleph circuit public back in '93 or so. A different matter, yes?
On another note: You posted Nelson about transmission lines on the AVS site. (By the way, thanks for bringing that to our attention. I find it quite intriguing.) I played with transmission lines for years, and have a fairly extensive set of notes on it somewhere. If I can find them and if you're interested, I'll be glad to share. I also seem to recall that there's a TL ring. I'll see if I can dredge up a site for that. Finally, Fried made TL kits for years in various configurations, with full diagrams and dimensions. I don't know if they were distributed down yonder, but for every kit they sold, there's a set of diagrams in someone's attic. I remember the "O" in particular as being very nice sounding. I may have some of those diagrams, too.
Petter,
I was envisioning two Aleph rear ends. One for each half of the balanced circuit. Is that what you were thinking, or were you saying to load the X front end into one Aleph rear?

Grey

[Petter]

I was pertaining to loading an Aleph rear with an X front. One very cool way to do it would be to use large offsets (R36,R37 on page 1) and drive the bottom section normally while the top section was driven symmetrically from the other half. It would probably be quite nice and still not be positive feedback like the original.

I don't personally see a very good use for Aleph at the rear -- but you try it.

[Jakeh]

There is always the near 50% efficiency of the class A complementary output stage, as compared to the basic 25% for the constant current source of the Aleph (minus the clever bit).

[Eric]

I have to say that I have been concerned about this thread since it first showed up here. Most organizations do not take kindly to reverse engineering of products, and often time these actions are strictly prohibited by licensing agreements, warrantee registrations, etc.

I'm very happy to see that Nelson is so flattered at the attention his designs are generating in the DIY community. Mark, I think you hit the nail on the head about mutually exclusive DIY & purchase audiences!

[Jakeh]

Whoah! While I agree thoroughly with your comments about Nelson Pass's generosity, I think the reverse engineering acusation has to be put in context - no-one is stripping the circuit boards, photographing them and assembling a compeitor product! The patent information is there in the public domain for a reason - that is the trade-off a patentee makes in return for his protection. No-one here is seeking to exploit this for commercial gain, so even if we were discussing a design based on a B**e patent it would be perfectly above board.

As for the rest, it is pretty much a stab in the dark (albeit based on deductions from information that Mr Pass has published), and I'd guess there are more than a few areas where confidentiality is more effective a protection of the circuitry than patent (as well as the depth and breadth of experience NP has on his side). I didn't see any cascoding on Petter's original circuit...

[vdi_nenna]

I was going to stay out of this, but...

A few years ago Nelson wrote to Audio Electronics Mag and said that he wanted to quit giving out his ideas to the DIY community because his designs were being copied and sold to the public by another group. That is stealing. Plain and simple. But Nelson didn't stop sharing, thought; it's been a while since he's put out a design in A.E.. (The last thing I remember was Op-amp design from dedicated transistors.)

The Aelph designs are posted clearly on his site. If he was worried about DIY'ers recreating his design and selling them for profit, he wouldn't put them up there because there are people out there who have the money, equipment and knowledge to really get it done.

As for reengineering the X-series amp, well that's touchy, but think about this. It doesn't make it any more ethical, but people who can afford the X-Series amps, they don't bother DIY'ing anything. They are too busy making more money!

The man is no fool. If it were really jepordizing his company, he'd pull everything, including the service manuals. Then, we'd have to pay for them, like other companies have clients do.

Just think, $24k for a set of amps. How much is that in parts and man hours for an amp like that? And, that's one amp (pair). Most of us couldn't slap a label on an amp and say, "Here I am! Buy this!" He's worked at this for a very long time! The man knows what he's doing! He wouldn't have said, "...I'm flattered." He would have said, WHAT ARE 8-BALLS TRYING TO DO TO ME!

Vince

[GRollins]

I'm not quite so sure as some that DIY and potential customers are different groups. The logic seems self-serving. I have known overlap between the two groups (both back when I worked in the industry, and now). After all, even those with means to buy Nelson's equipment have hobbies, yes? But you're assuming that none of them do electronics for a hobby. Curious assumption, that. Not all well-to-do people go yachting on the weekends.
I myself used to straddle the line. I could (marginally) afford the best high-end equipment. It'd nearly kill me, but I'd do it. I'd eat bologna for a month to make up the difference, but that was the price I paid. And I had a top of the line system to show for it. Serious, great sounding stuff. (My Thresholds, Conrad Johnson, etc. are a relict of those days.) *But* I also built my own, even then. Crossovers, subs, whatever.
Sadly, I can no longer afford top of the line stuff. The price of high end gear has increased at roughly double the rate of my income, and it's just not an option. Now it's DIY or die, because I'd surely be unhappy without my music, but I will not resort to taking something that isn't freely given.
My thanks to Nelson for making designs available to me/us that make my/our DIY choices more varied. As I've said before, I like both tubes and solid state. They both have their place in a good system; it's nice to have both sets of tonal coloration on my palette as I try to balance the sound of my system. I'm pretty good with tube design, and could probably come up with a decent solid state amp if I had to, but it's always nice to see other ideas brought to the table. Fresh thought is stimulating. But if Nelson withdraws his support then I, for one, will not cross the line.

Grey

[vdi_nenna]

Grey, I had a whole response to what you said, but I'm going to drop it, because I think it's non-productive. You disagree and that's good. I just want to build an amp and have fun doing it. But, I'm sticking to my opinion.


And Grey...stay away from bolona, it's bad for you!