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basspig

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basspig last won the day on May 2 2014

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  1. The one that's drifted off into the realm of 'snake oil' subjective evaluations of sound quality. ?
  2. With internal tube resistance being hundreds to thousands of ohms, there's simply no way a tube can be a better voltage source than a transistor, whose ability to deliver current is at least two orders of magnitude greater than that of any common audio output tube.
  3. I read briefly through the whitepaper and I get your point, but I disagree that a good voltage source amplifier is large and expensive. And with class G/H designs, efficiency is pretty good nowadays. Class A is the pig in the room as far as efficiency, and for that, high power output is going to be costly in terms of cooling and power consumption. It's been known for over 50 years that speakers designed during the tube era sound 'dead' on SS amps. It's as you say, because the tube amp will increase its voltage output at the resonance of the speaker and maintain almost constant power to the load that is varying in impedance across the frequency band. Modern speakers are designed to work with modern amplifiers though. I was an all tube guy for many years. I held out until the late 1970s with my home brew tube monoblocks. Nothing sounded fatter, played as loud, or seemed as tolerant of overdrive as my tube amps. My first SS amp was a Fisher TX200. It crackled when it ran out of gas. Years later, someone loaned me a 40wpc Dynaco SS amp. Same thing. Seemed to lack bottom end. In the late 1970s, I picked up a Marantz 2270. For sure, this should have more bass. It didn't. It sounded grainy, thin and brittle and when driven hard, it would oscillate and that would manifest as audible clicks or chirps in the tweeters. A year later, I brute-forced it and got a PL D-500. That broke the barrier, but it wasn't perfect. It wasn't until 1984, when the MOSFET amplifiers came along, and would finally replicate the clip tolerance of my tube amps, while offering much wider bandwidth and power. Now those Lowther speakers are interesting, but they come with a great many (and ridiculous) compromises. The size of the horns, just to get down to 50Hz, and the problems of intermod using a single driver across the whole band. Well, they're probably okay if playing string quartet music, but pipe organ, or marching band music? I don't think so. My experience with seeking out amplifiers for reproducing low frequencies has taught me that for power efficiency and woofer control with exceedingly low distortion, a transistor amp is the way to go. Nowadays, I run industrial amplifiers which can work all day into 1Ω loads without strain and damping factors in excess of 2000. And I do get Nelson's point about overdamping. I did lose some bass by going to the much higher gauge wire. But the bass I have now is more accurate without the boom. If I were to try to recreate my present system with vacuum tubes, I would need 15 tons of air conditioning capacity and a direct feed from Niagara Falls. I simply could not even afford to turn on the system for one hour. The present system is clean, quiet, cool-running and relatively maintenance-free. I could never see myself going back to vacuum tubes.
  4. I think you have it backwards. A voltage source will (theoretically) try to deliver infinite current into a dead short, whereas a current source will try to maintain the current flow at the same value in to a range of load impedances. An ideal voltage source has zero internal resistance so that changes in external load resistance will not change the voltage supplied. An ideal current source has infinite resistance so that changes in external load resistance will not change the current supplied. A well designed transistor amplifier will be relatively unaffected by the load, within the limits of its design. Such an amplifier has some commonalities with the pass bank of a regulated power supply. Of course, some feedback is necessary to maintain the regulation of a DC supply, and the same holds true for a circuit used in audio amplification.
  5. Vacuum tube amps, due to their high output impedance making them current sources, are affected drastically by the impedance curve of the load/loudspeaker. Solid state amplifiers, especially the more massively parallel ones with large numbers of output devices, appear as being close to a pure voltage source. They are nearly impervious to the changing load impedances of a loudspeaker. Some early SS amplifiers of poor design also behaved in unexpected ways, such as breaking into oscillation, with certain loads.
  6. YouTube changed the links so some direct links may fail... okay, so here is the link to the whole enchelada of videos for the Bridgeport Symphony.. there are about ten new ones from the December concert up there now. As always, be sure to watch in 720HD, else the colors looked ragged with YT's compression: http://www.youtube.com/bridgeportsymphony#p/u
  7. My recording of the December concert of the Bridgeport Symphony is now on YouTube: "Scheherazade", final movement, by Rimsky-Korsakov: Enjoy our best concert yet!
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