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No, I'd say that there are not-so-great amps that also fall under those categories, and which may contribute to giving a type of amp a bad name if a less than good design (or less than good match for the speakers) is what you have been exposed to.
Good point - but I would also say that an amp that is sensitive to speakers and other components is not a great amp. A great amp should do its job no matter what it is driving (OK, as long as it is not just an iron nail across the output terminals).
And why not?
Nope. I disagree with you on this one. I'd rather have an amp that is better suited to a particular speaker than a jack-of-all trades amp.
Many respected amplifier designers frown on using negative feedback because it creates its own set of problems.
The problem with valves is that you usually have much less gain in your typical valve amp than in a semiconductor amp, and that seriously restricts the amount of feedback you can apply to reduce distortion.
And many other respected designers don't. Neither is any sort of a factual argument for or against feedback. What are your factual issues with feedback?
I gave you citation with the Nelson Pass experiment from six moons and I am done with the discussion of the drawbacks of applying negative feedback to lower distortion numbers.
Sure. I just need to point out that six moons isn't exactly a scientific publication.
Nelson Pass wrote the article did the testing and generated the graphs. he is a professor of amplification if there ever was one
Nope. I disagree with you on this one. I'd rather have an amp that is better suited to a particular speaker than a jack-of-all trades amp. I mean, c'mon, your "great amp" would exclude fabulous designs such as SETs and OTL amps. Not to mention the low-watt SS Class A FirstWatt beauties of Nelson Pass. Even with much more conventional amps and speakers, I have found amp-speaker matching to be crucial. My SP Tech Minis (88dB or so) worked great with the Hybrid Butler 2250 I had paired with them, and didn't sound as good with the Rogue Stereo 90 (which was providing more than adequate power in my smallish listening room). My Von Schweikert VR-4s (~91dB) on the other hand sounded (and are sounding as I type) better with the Rogue Stereo 90 (now Super Magnum upgraded) than with the Butler 2250. Neither was terrible, but it was a nice improvement to really dial in an ideal match for my different speakers. To each his own, I suppose.
I just ordered a Sphinx in black with the remote control and I should get it on monday or tuesday. I have some holy grail 12AU7's like Amperex Holland 7316's and Siemens nickel plates sitting here and I have a matched pair of grade A Psvane 12AU7-T II coming here shortly too so it may get interesting
Bruno Putzeys has given several talks on negative feedback and his work speaks for itself, so.
You can pretty much google them or there should be links in the Hypex circle for a few of them. The man is a genius, and he was actually designing tube amps when he was a teenager. Anyway, with his class d Ncore amps, lots of negative feedback is one of the tricks that makes it work the way it does. Welcome to 2013.---The amps in the OP look pretty cool for the money Look forward to your impressions Bunky.
