Anyone can reduce distortion with global negative feedback with gain supplied by an IC. This is just a technical fact. In the old days, 25 years ago, I did not want to make a small power amp that could adequately drive the 25 ohm load (or so) that my design would have required. Therefore, I designed the first stage, open loop, and relied on Class A, and AC balance for low distortion. The noise was essentially the same as any design, today, especially with a minor resistor change.
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Well, 25 years passed; and now we have high speed high voltage JFET input opamps, able to deliver high current into 25 ohm load, for $3 a pop.
You couldn't do such for the money, 25 years ago. Isn't this amazing?
I should add that the Vendetta phono preamp is indeed an amazing phono stage, for the technology level of the early 80's, but obviously outdated today, at least in terms of distortions and dynamic range (headroom).
And after 25 years they still can't match a good discrete stage in sonics.
Prove it. Wait, no, you have to prove first the audibility of speaker cables.
Don't think so, but at least you could do it today better than 25 years ago.
Then it will be no better than 25 years ago. Moreover, given that those JFET devices are still unobtanium (according to your own measurements) it will actually be worse than 25 years ago.
Please, let us all understand: Linear Systems still does not have the experience with making these ultra low noise jfets that Toshiba has had for the last 30 years. Every major manufacturer has tried to buy a large supply of the original Toshiba jfets, rather than rely on Linear Systems jfets, that have been slow in coming, and still have more variability than one would like, for production. Still, they are the future, not Toshiba, for super quiet jfets. They will be more expensive, to be sure, but even now, for most applications, they appear OK.
Please go on. VA rating, internal resistance, anything more subtle? And we should probably not leave out the diodes either. Fast, soft recovery?
The main thing for me is the TYPE of transformer. For many years, we only had E-I transformers, and we wanted 'more'. Some toroid transformers were produced, but they were very expensive, as they took special equipment to put on the windings. However, we found that toroid transformers had a special problem: They passed RF, etc and not just 50-60Hz. Now, especially for preamps, we use Split C or D core transformers so that the input and secondary windings can be easily wound and remain separate from each other. Power amps could use this type of power transformer as well, and some manufacturers use them, but they are difficult to get in very large sizes.
Yeah, if you just use a stock toroid without an electrostatic shield between the primaries and secondaries.
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