Technique behind Aleph X0.2 Volume Control

[rsbay]

Hello,

has anyone an idea how the volume control in the new Aleph X series preamplifiers is working. I saw a picture in a German audio magazine and I noticed that Nelson switch the resistors with semiconductors. In a first step this is very easy to do - there exist a lot of semiconductor switches on the market - but I expect to get a real good volume control you need more like that. How is the volume control made ?

Regards

Ralph

[Ian Macmillan]

Even if they did I am not sure they would share it. This would be Wayne's masterpiece and the technique used is part of a long overdue patent application and until it is granted it cannot be shared. That said, Nelson did throw down the gauntlet some while ago when he suggested that we try and reverse engineer it. Curiously nobody has taken up this challenge to my knowledge.

[BrianDonegan]

According to the manual, it already is patented. Anyone know the number?

[Nelson Pass]

The patent is still sitting in the patent office after 5 years,
which is why I no longer consider patents a good investment.

[moamps]

Originally posted by Ian Macmillan
.. Nelson did throw down the gauntlet some while ago when he suggested that we try and reverse engineer it. Curiously nobody has taken up this challenge to my knowledge.

You tease! There was no challenge. There is a special challenge opening ceremony first when Nelson waves his wand and offers a free Sponge Bob T-shirt (alternatively, pink flamingo slippers) for the winner.

Regards,
Milan

[Zen Mod]

why I have impression that this "reverse engineering" will demand unusual amount of lateral thinking capability?

[Netlist]

Originally posted by rsbay
...switch the resistors with semiconductors.

Think heavily biased mosfets and a big heat sink to cool the device.

/Hugo

[Ian Macmillan]

Originally posted by moamps


You tease! There was no challenge. There is a special challenge opening ceremony first when Nelson waves his wand and offers a free Sponge Bob T-shirt (alternatively, pink flamingo slippers) for the winner.

Regards,
Milan

Not so, Nelson posted some while ago...

"If you want a truly fantastic semiconductor-based attenuator,
back engineer the volume control from the X series preamps,
which uses bipolar switches.

It outperforms the other stuff we've seen by a factor of about
10 in every parameter, and was developed by Wayne, who
has a patent pending on it."

I take this to be a challenge.

[Nelson Pass]

Not much of a challenge since anyone who wants to can take
one apart. Of course you might have to buy one to do
it. Also, it's all SMT so get yourself a microscope.

[Ian Macmillan]

Originally posted by Nelson Pass
Not much of a challenge since anyone who wants to can take
one apart. Of course you might have to buy one to do
it. Also, it's all SMT so get yourself a microscope.

I hadn't appreciated you meant it so literally - I thought you were challenging the DIY community to come up with something like Wayne's idea based on the various crumbs already scattered. Personally I think it would be much more fun even though it is unlikely that we would arrive at the same result (or maybe not arrive at all).

Taking one apart only tells so much. OK, so one can duplicate the circuit but that does not necessarily give much insight as to how it works. The latter is more intersting in my view although building one would be fun too.

I already bought an X2.5 (great preamp) but so far I have resisted the urge to take it apart. In any case I wouldn't be comfortable with sharing anything I learnt in this forum precisely because of the patent fiasco. I'm rather hoping that you will share the 'secret' when you are ready, presumably when the patent is granted.