pass x2 + dcx2496

[george a]

Hi All

With the schematic of the X2 released , i was struck by an idea.

The dcx2496 digital crossover has copped some flack for its IC based input and output stages..
I wonder if it would be possible (or even desireable ) to replace them with the input and out put stages of the X2.???

No offence meant....but keeping my head low in case of flames.
How dare I even contemplate a cross between PASS and Behringer products ......-yes i should probably be shot at dawn...twice.
cheers

[Nelson Pass]

Certainly you can consider replacing the analog stages -
I have one of these, but I haven't looked at it with an eye
to doing such a thing. Of course I would need to get a few
more diopters in my glasses to even see the circuits.

My biggest issue with op amps is that they are designed with
such enormous open loop gains which is entirely unnecessary
for most audio use. As a result, most of them to be unstable or
marginally stable at low gain figures, and it seems to affect the
sound. My opinion, anyway.

I built a number of XVR1 prototypes early on with various
"high quality" op amps, but got the most satisfaction from a
simple discrete circuit.

[george a]

Hi Nelson
Thanks for your reply.
I must say I'm a litlle surprised that you have one of these dcx units.
My main intention was to build one of the MOX type circuits but an analysis showed that it would probably take 2-3 yrs of increasingly scarce time, during which increasing domestic pressures would have made it more and more politically difficult.
The arrival of the dcx in the household was actually greeted with approval based on what the event represented time wise.

Another issue is that the DCX recently had a massive price drop, so much so that one could (almost) consider it worth a play with just out of curiousity (almost disposable even).
Locally the RRP has dropped from AUS$799 to $499 -street price even less.

Ultimately the problem is it might still take 2 yrs to mod the dcx....

Again Nelson thanks for your excessively kind contributions to this game..

PS, I have recently completed an A5 (very nice indeed) and have set aside a fine bottle of West Australian red (Margaret River) for when Mark Finnis drops around for a listen after tweaking, I'm sure we'll drink to your health....

Cheers and good health

[Nelson Pass]

Originally posted by george a
I must say I'm a litlle surprised that you have one of these dcx units.

I go through a lot of toys - keeps me from buying cars and boats.

[george a]

"the difference between men and boys is the price of their toys"

probably has a ring of truth to it (as my wife keeps pointing out)
Quote.."When did you get that?, What is it?, how much did it cost??"

[Nelson Pass]

Originally posted by george a
Quote.."When did you get that?, What is it?, how much did it cost??"

A lot easier than "When did you get her? Who is she? How
much did she cost?"

[mastertech]

mY ZENS ARE AWESOME
THD 0%

[Nelson Pass]

Originally posted by mastertech
mY ZENS ARE AWESOME
THD 0%

Glad you like them, but 0% they are not.

[mastertech]

Mr Pass my state of the art testing setup read 0% thd this
circuit i have not published, i am really sceptical about it too
perhaps due to a mistake of mine

all my zens sound incredible i couldnt believe you could make
such a top class amp from components off your junk box

the distortion of them could be coming from the temperature
stability of power fets causing nonlinearities and harmonic distortion

Mr Pass, now,i wish to build a huge zen and the idea i have in mind is parralleling smaller power fets and their load resistances
will there be spreads causing un equal branch currents in both
fets and load resistors, your input will be highly appreciated
and do you know of other technigues to increase power using
smaller current devices a link to a diagram would be great
thank you

[Nelson Pass]

You can match devices Vgs and use Source resistors
to equalize the current sharing. It doesn't take much
resistance, say .47 ohms to do the job.

The only problem is that the junction capacitance piles
up and this gives distortion and rolloff at higher frequencies.