best preamp ever - cost is no object

Herman, the genius comes from the use of innovative circuit topologies but it is true that in general audio circuits are simple in general terms compare to complex circuits designs used in control circuits, automations, instrumentation and data acquisition circuits. Those are facts that any competent engineer will tell you.

No, not all circuits sound the same and I agree that great measurements don't always translate to great sound; you are changing the scope of this discussion and are making inferences and allegations that I have not made. So please re-read the post and make notes of my statements before you make these grave assumptions.

As far as ego, I'm dealing with facts. How many audiophiles here have offered their systems to be judged by a "reviewer" like I have here; it is quiet obvious that I'm pretty confident in what I have been able to achieve and where my system and knowledge stands right? Why should I hide the facts?

I have nothing more to say so I will give it a rest and just wait for Ryan to either come over or invite me over to listen to his reference. Then we can start the discussion again with more facts and not assumptions.

Carlos269, having serviced out a few Cellos in the past I was amazed at the poor parts quality. Yes, they are junk, nicely packaged and nicely built. With a price tag to throw you off.

FWIW using a variety of NOS tubes to tailor sound is not merely tone controls- if that were the case we'd have solved the issue years ago :) NOS tubes also sound different because they have different distortion characteristics. Some of those distortion characters are easily heard- just as they are in solid state devices (that are supposed to be low distortion). NOS tube are not used because they sound 'brighter' or 'darker' alone, it is also because they may sound smoother or more detailed. When you can show a "tone control" circuit that can increase detail and smoothness and noise floor *without* changing tonality you will have a marketplace, trust me.

You might compare the use of NOS tubes to fine wines and their differences. The analogy is weak but the complexities of a good wine do have something in common with the finer traits of a good tube.

In these brief few paragraphs I have not really given proper due to what the tube rolling thing is all about- and in my own system/designs I avoid using them at all, as I am interested in improving the design without the variable of the tubes, so I always use the same tube types (once having sorted which ones appear to sound right). So while I acknowledge that tube rolling can make quite a difference, at the same time the technologies that the tubes are operating in make, in my mind, a bigger difference.

It may not be that in their expression that anyone posting here has satisfied your 'scientific process', but my experience has been that most audiophiles that are at all serious are surprisingly scientific- I don't think any of them are doing it by trial and error! If you could modify the character of a tube on the fly, this would be a lot easier. But you can't so you may want to change tubes if you want to get the last drop of performance.

Carlos, I don't think the circuit topology must be innovative. It must be well implemented. As you say, the circuits are simple. While this may be true on one level, they are extremely complex on another. Otherwise one could simply copy a circuit and end up with the same sound. The complexity is the huge number of variables you face when you actually start to build. Given a simple schematic of a single tube amplifier it could be built an infinite number of ways when you factor in type of capacitor, resistors and other passive components, physical layout, grounding schemes, cabinet material and construction, wiring, etc.

There are thousands of different amps out there that have very similar circuits but all sound very different if you take the time to listen.

I have had my system evaluated by a reviewer, a high end dealer, and a high end manufacturer too and they were all suitably impressed, not that it means much of anything. Just another opinion in my book.

And yes, as far as ego goes you are dealing with facts. The fact is you have a huge ego. What impresses me is when people like Ralph put forth well reasoned ideas to support their positions, not when people like you tell me I should pay attention and tremble in your wake because you are "the bull."

Ralph,
Are you familiar with the many tube saturation devices in the Pro Audio world? These devices are design with just this purpose in mind. Beyond changing the tube saturation/distortion characteristics there are devices in the Studio world that go far beyond what is possible in the audiophile world.

It was my understanding that on top of being an audio designer you are also a musician so you should be familiar with devices like SPL’s Machine Head which let you change tube saturation and distortion characteristics in the digital domain. These are convolution devices but many devices are analog and work of the tubes’ originals saturation/distortion characteristics.

By the way, my experience and the experience of others that have opened up Cello equipment concurs with yours; they were over-priced boutique pieces which did not reflect their asking price. What I was simply trying to do was to show Ryan that although I do not make use of graphic equalizers many mastering luminaries do use them.

The top equalizers that I would recommend are: SPL PQ Mastering edition, Avalon AD-2077 and GML GM-9500 try to tell me that any of those mastering "parametric" equalizers are junk. I personally prefer psychoacoustic equalizers which is a different branch of sound processors.

Your approach of taking the tube variable out of the equation is the correct approach as your design should try to minimize the effects of different "vintage" tubes as much as it is possible.

Herman, Lets get together and listen to each other's systems and let's take it from there! Should we? Where are you located? Maybe I can pit stop at your place on one of my frequent trips to Shanghai, China.