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In the Forum: Audio Discussions
In the Thread: Building “Zarathustra II” amplifier
Post Subject: Building the Zarathustra IIPosted by nautilus981 on: 4/8/2010
Hello, would it be possible for us to see the diagrams and schematics behind the Zarathustra II in the same spirit as the Melquiades was conceived, noting that the best of ideas are formed with the purest of sentiments?

It is Dima’s and my strong conviction that the most beautiful in this world comes to our lives for free as a gift. Some people gave to us a gift of thier experiences. We in our turn would like to in-reach public (no mater now moron the public might be in it’s majority) sharing the Melquiades.

I will try to make an addition to this site in my own way, not knowing whether or not you have heard of it, or whether you will find it to be useful or not. Browsing through Romy The Cat's playback, I've seen that Romy uses Guy Hammel’s Placette Active buffer, and states that it offers the absolute best transparency for a line-level analog device.

A few months ago, I heard of the Lightspeed preamp. The Lightspeed preamp works in such a way fundamentally that it is going to offer the best level of transparency for a preamp, bar none, given its use of light-dependent resistors, that make it so that there are no moving contact points in the signal path, and thus no loss of information - basically a volume changer that cannot alter the signal path in any physical way. The lightspeed preamp is thus the ideal preamp.

Some quotes:

I bucked up and bought a Lightspeed Attenuator from George. I've played music through it for a handful of hours, so I have but a preliminary perspective on its sonics.

I think George has a winner on his hands. First impressions are: the unit is quiet as the night is dark, it excels in coherence and resolution, and high frequencies are to die for---holy cow, no grate or edge, and what delicacy. The HFs alone are worth the price of admission.

Comparison preamps are an Emm Labs active pre stuffed to the gills with teflon bypass capacitors, a DIY Paradiso TVC and an Audio Consulting Silver Rock TVC. The latter is my reference; it beat out a Placette I once owned, and comes close to the LA, but mucks up the HFs in comparison.

Thanks for a great product, George. More listening will tell, but the LA seems an appreciable step forward.

Wow, what a preamp! Shockingly good! I can find no fault with its sonics. That, I suppose, should be expected because it so elegantly solves so many problems associated with preamp design.

I've had several, mostly involuntary thoughts listening to it, like, "geezus, that actually sounded like a cymbal." I won't belabour the others because they all practically come to the same point.

Best pre I've heard by a considerable margin. George deserves a fricken award.

Another day of listening and I have yet to hear anything I dislike about this unit. Everything is three notches more realistic through it.

Why does the Lightspeed perform so well? I'm familiar with the difference changing a cheapo resistor for a Vishay makes. That difference is considerably smaller than changing my previous reference pre, the AC TVC, for the Lightspeed, and the AC beat out a Placette. Personally, I'd place my money on George's contact theory.

I tried to explain this contact phenomena before about 200 posts ago in this thread, I’ll try this time to explain what I found a bit more clearly.
First it had nothing to do with corrosion of the contacts in potentiometers and switches, it was the fact that all had a very small pin point size contact area between the surfaces. In potentiometers it is even worse because the pressure is so light as not to wear out the carbon or plastic resistance track, Switch resistors are almost as bad especially if the rotary switch is of the single leaf variety, dual leaf is better one each side of the common, but still I saw a problem even with these.
The way the problem was found, I managed to borrow for a day a very trick digital 10 gigahertz for memory storage oscilloscope from the CSIRO a massive research company here in Australia, god knows what it was worth 50k or so it made my high end Tektronix look like a toy. With this scope I was able to store and magnify the corner’s of a cd level 1 to 2 volt 1k square wave, and what I saw was an extremely high oscillation embedded in the original this oscillation disappeared once I put extra pressure on the wipers of the pots and switches with a non conductive toothpick, all I can say is that the rise time is 100’s of volts per micro second and it causes the contacts to become poorly conductive at these levels and creates a diode effect and tries to rectify the AC music signal into DC, I’ve for want of a better word called it contact bounce, you guys call it what you will but the proof was there and disappeared once more pressure was applied, in the case of RCA connectors the area is 10 to 20 times larger and the pressure much higher, so the phenomena does not seam to happen, but I think maybe it does, ever wonder why your system sounds cleaner after you’ve done a clean up of your RCA’s.
And please all you non believers, don't say anything till you've seen it for yourself, on a scope like I had the good fortune of borrowing. Not on a toy 400mhz Tektronix like mine, you won't see it.

Cheers George

Here you will find directions on how to build it,

Here instead is the discussion on it:

The reason as to why I'm interested in the Zarathustra II is because of Romy's comments on the first Zarathustra. I'm on the market for a >200 watt power amplifier that I would like to match with an Aurum Cantus Music Goddess 6 mk2, and want one that is fundamentally correct - as correct as possible for a given price, given that the word "good" has been overused. We all search for the same things, anyhow Smile By going with DIY the cost of getting an ideal (for a given price) power amplifier is going to be greatly reduced, due to all of the greed of both the manufacturers and middle-men involved, that is almost always associated with high-end audio.


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