lynn_olson
Responses from lynn_olson
| 300b lovers If a cool room is important, you want Class D (90% efficient or better) and speakers that are more than 1% efficient (a true Theile/Small 92 dB/meter/watt), as well as switching (not linear) supplies for all the other audio components. That’ll mak... | |
| 300b lovers Pindac has described the stage Don and I are at now: tuning the subjective balance ... there are a couple of nodes in the circuit where parts selection is quite audible, and we’re fine-tuning that. I wrote an email to Don a couple of days ago tha... | |
| 300b lovers I was there. Thom’s amps did not use interstage coupling (at the time), so 8 watts is pretty much all she wrote. Frankly, I was kind of surprised ... I knew Thom’s NiWatts were maxed out for all they were worth, but audibility was surprisingly low... | |
| 300b lovers It is difficult to predict real-world distortion from idealized triode or pentode models. The models assume tubes with perfect physical assembly and ideal emission characteristics. In practice, grid windings are not evenly spaced, grids are tilted... | |
| 300b lovers Hi, CuriousJim! I am kind of dubious about any KEF speaker being really 91 dB/meter/watt. That’s almost 1% conversion efficiency, and believe it or not, that’s quite high for the mainstream market, and especially KEF. True efficiencies between 85... | |
| 300b lovers A good way to visualize the difference between even and odd-order distortion harmonics is to imagine a sine wave ... a perfect, happy little sine wave. That's the original signal. * Now, use a single diode to clip one side of it ... say, the posi... | |
| 300b lovers The house I lived in back when I was in Portland had a ceiling like that, with a panoramic picture window overlooking the Oregon Coast Range behind the speakers. The very first PP 300B amp, the Amity, had a vast, CinemaScope soundstage. Once I hea... | |
| 300b lovers What’s odd is that I have trouble describing the sound of my own gear ... this applies to Shadow Vector, my loudspeakers, and my electronics. I aim for natural, open sound that is free of electronic artifacts. If there is a residue of coloration, ... | |
| 300b lovers Well, I tried that with an amp I once called the Aurora. SE input, and if memory serves, the conversion to PP prior to the driver, which was PP. The problem is the input tube has a high output impedance, which enormously complicates the transforme... | |
| 300b lovers Let’s talk a bit about distortion, particularly in a DHT driver. It defeats the purpose of using a very low distortion 45, 2A3, 300B, or 845 if the driver has more distortion than the DHT itself. You might as well use a much cheaper power pentode ... | |
| 300b lovers The Statement ... or Blackbird ... or whatever it’s called, is pretty sensitive. Don told me 1.5 Vrms to full clipping, and my gain calculations indicated a bit more sensitive than that. Since there is no RC loading anywhere, and all the cathodes ... | |
| 300b lovers As for the tech, none of this is difficult. They will know how to connect and bias the floating paraphase phase inverter ... plenty of old schematics out there ... and the rest is a matter of chassis space and heater current for the new drivers. ... | |
| 300b lovers Unfortunately, revising the driver away from the usual single 12AU7 means another hole in the chassis, and a pair of octal sockets at that. And split power supplies means another power transformer and rectifiers, although it relaxes the endless se... | |
| 300b lovers The interesting thing is that "conventional" amps like PP KT88’s can be substantially improved as well. For example, floating paraphase phase inverters instead of split-load inverters or Mullard long-tail pairs. The phase division isn’t as precise... | |
| 6DJ8 vs. 6922? They are interchangeable. The 6922 is the commercial-grade version, a step above the consumer-grade 6DJ8. In practice, it’s been a half-century since the phone company, avionics, or the military used these tubes, and they were replaced by FETs in ... |