Advice for Linkwitz Orion system with Nelson Pass-style pre-amp and amp

[GeorgeBoles]

Nelson (and Grey),

What you are saying is roughly what I meant. I had no idea that such a HUGE reduction of op-amps could even be possible - clearly the ideal solution. (As you described, the Orion crossover has essentially one op-amp per function.)

It is still possible to imagine that changing all the opamps for discrete versions (without reducing numbers of opamps) might not produce an improvement worthy of the effort.

When I was commissioned to rework the cutterhead electronics for Mobile Fidelity, ...

Ahh ... Mobile Fidelity used to be my heroes ... Dark Side of the Moon, Abbey Road, White Album, Beethoven's Ninth - George Solti (the last in particular makes the current CD iteration just pale into boringness) ... whistful sigh ....

Thanks,
George.

[Nelson Pass]

I spent some time reviewing the (possibly earlier version of)
electronics for the Orions, and it is clear that you can replace
something like half the gain stages with discrete op amps
and buffers and get the same nominal functions.

There is a potential problem here, though. I am hesitant to
step on his toes, since he sells the circuit information (at a
modest price) Perhaps someone would want to work on this
aspect - negotiating permission to proceed with such a project.

[Andersonix]

Originally posted by Nelson Pass
I am hesitant to step on his toes, since he sells the circuit information (at a modest price) Perhaps someone would want to work on this aspect - negotiating permission to proceed with such a project.

SL will be here in London on Nov 13 for an AES lecture. Perhaps somebody can bring up this topic with him. (Maybe myself with some encouragement?) I would love to build a simplified (AND discrete) version of Orion (or Pluto). What would such a 'negotiation' entail?

[Andersonix]

Today's the big day when Linkwitz is in (London) town. Anyone have any clever ideas on how to raise the subject with him? Otherwise I'll just fumble my way through, mentioning that two or three members in these forums are anticipating a discrete version of his electronics. (And, ahem, would he be so kind as to redesign them for us...?)

[paulb]

I think there would be more than 2 or 3. I make it 3 or 4.
I believe Nelson was offering to do some of the redesign, he was just want SL's permission to proceed.

[Andersonix]

Perhaps it needs more than just permission, as I could imagine some actual collaboration with SL being very helpful in seeing this through. I suppose I should just start off with asking what SL thinks about NP having a proper go at it for DIY use and see where the conversation goes?

[GRollins]

I believe you're reading a bit more into Nelson's post than he intended. Surely one of you guys is up to putting together an opamp, yes? Once you get that far, just put it in a DO-loop and repeat until the circuit is done.
Go get Nelson's paper on opamps and have at it.

Grey

[apassgear]

George,

As much as has been said on the amp topic I would be hesitant to mix gain and no gain amps (F4) on a multiamp system. You will need to pad down (pots on the active xover?) the gain amps to drive the speakers.

This only means that the gain amps will be driven near ground level voltages which to my understanding is a no,no. Or I'm wrong?

[GRollins]

So build a crossover with gain...problem solved.

Grey

[apassgear]

Originally posted by GRollins
So build a crossover with gain...problem solved.

Grey

Yes, add another opamp?

Who needs then a nice line amp like the to drive a bunch of opamps?

Gee guys, seriouly something isn't sounding good here...