tubes and analog

>>we develop a totally new mathematics theorem to make the transistor full linear<<

What kind of fluff is that? I'm not familiar with any of your designs, but coming up with some new equations on paper does not change the laws of physics. Active devices follow certain behaviors and have been well established. On one end of the scale is the triode, the most inherently linear amplification device used in audio. At the other end is the bipolar transistor (ok, maybe an IGBT is worse). In the middle are JFETs, pentodes, MOSFETs.

The bipolar transistor has a nearly perfect logarithmic transconductance. Hard to beat in that respect. But exponential is not proportional (linear). No theorem is going to change that.

If you have, however, invented some new circuit topology that does what you claim, then I suggest you patent it immediately. Silicon Valley is going to pound your door down.

>>more SS designs come with NON feedback design<<

Well, I think this is a little exaggerated. Most SS designs on the market employ opamps. Only a handful use open loop discrete gain stages. Perhaps this number is growing, but I hardly think it is dominant.

>>It is untrue that there is a technical limitation topology<<

What I didn't make clear here was the basic difference between class A and class B stages. As far as I know virtually all opamps run class AB. The output signal is driven in one direction by one device (transistor), and in the other direction by a second device. They keep handing off the signal. Only during a small crossover window do they both conduct. Making this window larger can help. Making the window full scale turns the amplifier back into class A. No device ever turns off.

In contrast, a class A stage is driven by a single device. It is always on. There is no cross over or handoff. This is the difference between a 2A3 SET and your typical SS amplifier. Why is it people will live with a flea-powered 2A3 when they can have 50 watts out of an LM3875 power opamp? Because of the micro detail. The SET is running full bore at idle. It excels at small signals and the distortion becomes vanishingly small. By comparison, the class AB amplifier excels at large signals. But it's distortion rises as the signal gets smaller. Exactly the opposite of the 2A3. That is an example of topology.

There are a lot of other topologies I can get into, but that example illustrates the point well.

>>tubes are harmonic generators<<

Yes. So is feedback. And the harmonics generated by feedback are far more insidious. They might be quite small in relative amplitude, but multiply with each pass through the amplifier, generating a lot of non-integer harmonics. That leads to the cold, sterile, and sometimes fatiguing sound of many high feedback amplifier stages.

SS stages that do not use feedback are also harmonic generators. Heck, every amplifier is to some degree. The question is, what sort of harmonics do you want to live with? I'll take a triode any day.

jh

In fact the odd-ordered harmonic generation that is a hallmark of transistors is a feature that runs counter to the rules of human hearing. We all hear the same way in this regard, and is not something that we can change.

The odd-ordered harmonic content we are talking about is used the human ear as loudness/harshness cues and occurs in vanishingly small amounts- hard to measure with conventional test equipment. But our ears are very sensitive to this type of distortion- finely tuned you might say.

Tubes do not make this type of distortion. So- in a phono stage, if you *add* this distortion, it will exist in the system right to the loudspeaker. So the phono section is the place where you really want to use tubes.

Dear Jh: +++++ " If you have, however, invented some new circuit topology that does what you claim, then I suggest you patent it immediately. " +++++

We are in this process.

+++++ " This is the difference between a 2A3 SET and your typical SS amplifier " +++++

Maybe the problem is that there is no more ( almost ) that " typical SS " topology. Today almost all preamps goes non-feedback, pure class A and discrete stages. Btw, we are using bipolars.

+++++ " Yes. So is feedback. " +++++

Like I told you almost the rule today are non-feedback designs. I think that you need some update about.

You certainly know every single tube technology limitations: very high output impedance, tubes are a noisy device " per nature ", tubes designs have higher distortions level than SS or hybrids one, tubes have heavy problems to reproduce accurately both frequency extremes specially the low bass where ( beteen other things ) does not have control over the woofers like the SS topology, tubes are untrusty: time to time ( very short time ) blow-up, tubes are not performance consistent: almost every single day sound different ( many people don't take in count because every day are in touch with their systems ). Jh you know that we can go on speaking about but this is not the subject: you and me know that there is nothing perfect in tubes or SS electronics.

Jh, the subject is that the " very old myths " about SS designs, fortunately, dissapear. Today we have very good SS designs as we can find good tube designs. The best of all is that today the customers have several choices that in the past don't.

Regards and enjoy the music.
Raul.

Here are some claims/concerns about the "wonder" product they've been trying to sell in the threads but haven't addressed:

>>Claims to have an unprecedented flat frequency response from 0.01Hz to 1 mHz<<

Well that’s crap as Spectral designs and others go beyond that.

>>Claim of 150 dB common mode rejection<<

More crap. The halves of a differential circuit must be matched within one - thirty millions (the deviation is one unit for thirty million units) - while even "dual" devices, made from a single crystal, are matched within one to a hundred. There is nothing in existence to measure such deviation. For the readership, in tube designs/ matching within one to thirty is common and OK.

>>Claim they match the discrete devices a million times as precisely as the others do.<<

Obviously, this is pure BS and more BS.

>>Claim distortion of 2/10000 (two - ten thousands of a percent - i.e.) the claimed distortion is minus 104 dB.<<

More crap. This is by far impossible to measure with any equipment on the phono level because they would have to have a device with the resolution to picovolts, and such instruments do not exist.
Additionally the claimed distortion figure is over 30 dB below (!) the theoretical noise floor for an MC cartridge, and 5 times as low as the lowest noise floor from any known solid state device in existence.

For any engineer, such ridiculous claims make the design and the designers look anything but real and serious. However, it makes for great promotion which is the issue now correct?

Hmmm, Audiofeil, why don't you ask him to explain it rather than using words like crap, BS, ridiculous, etc. You're posts have been nothing but antagonistic for so long it has become tiresome.

You keep attacking Raul like he's trying to sell his preamp, but I don't see you attacking Ralph when he speaks of the virtues of his products. Is this because you sell Atma's??? Why the hypocrisy???

I love it when manufacturers like Ralph and JCarr and Raul/Jose and Hagerman discuss their designs and thoughts here. There is valuable info to be gained from all of them and I hope they all continue to post so that we can benefit from what they have to say.

Unfortunately, Audiofeil, just like Raul has probably turned off many people with his posts, you have made it clear to at least me, that even in your native language you have a lot to learn about earning the respect of others.