lynn_olson
Responses from lynn_olson
| 300b lovers One of the maddening things about the original Karna amplifier was sonic variability. Some days, it would be a glimpse of Heaven, and other days, nothing special. It was always extremely transparent ... that’s the nature of the circuit ... but the... | |
| 300b lovers Back when I was playing around with 300B’s, I found that each brand had its "sweet spot". The authentic 300B’s, and the exact reproductions, seemed happiest between 65 and 75 mA. The European super tubes, between 72 and 85 mA. The monsters with gi... | |
| 300b lovers Charles1dad, thanks for the compliment ... much appreciated. Don and I put a lot of work into these seemingly simple amplifiers. DHT’s had a rather short reign in audio (much longer in transmitting tubes). It was only from the early Twenties ... ... | |
| 300b lovers Which returned the Blackbird to the original Karna topology, with far superior power supplies, and the luxury of interstage transformers specifically designed for the Blackbird amplifier. I give Don full credit for doggedly trying every possible ... | |
| 300b lovers Yup. Wires, transformers, and 1930's vintage tubes. That's the entire signal path, from preamp input to speakers. | |
| 300b lovers Direct coupling would have no effect on tube loading, which is responsible for the spectra shown. If we were to re-do the article, we’d try a MOSFET cascode current source load, as well as transformer coupling, SRPP, and RC coupling. We were surp... | |
| 300b lovers Investigated in some depth in this 1997 Glass Audio article by Matt Kamna (designer of the Whammerdyne 2A3 amplifier) and myself: Hidden Harmonics We found that transformer coupling had the most favorable distribution of harmonics ... by that, t... | |
| 300b lovers Alex, the Shishido 811 circuit is basically uncopyable, since it relies on DC flowing through the secondary of the custom interstage transformer that goes into the 811 grid. Unlike nearly all other audio circuits, this circuit operates the 811 pow... | |
| 300b lovers To sum up, we have a circuit with big, simple tubes designed no later than 1939, combined with 21st-Century transformers and power supplies. In that sense, it is a hybrid amplifier, spanning 84 years of time and technology. (If you want the Black... | |
| 300b lovers Hi, Alex! The original Karna, designed by me, and built in four-chassis format by Gary Pimm (of Portland, Oregon) in 2003, used a 5687 class of input tube. (The 6900, 7044, and 7119 all have the same pinout and similar operating points. The curre... | |
| Bacch Dsp, True stereo? Wait a second, has anyone in the Audiogon forums actually heard BACCH, or is this just repeating things said on the Internet? Not being snarky, I'm serious. | |
| 300b lovers Reflecting on a recent phone conversation with Don (he’s in BC Canada and I’m in Colorado, a bit north of Denver), I suggested that SET amps are kind of like a paint-box, and a much more fun way of tuning a system than messing with cables. If you ... | |
| 300b lovers I suspect any electrostat is fine. The weird capacitive/inductive load will not bother a zero-feedback amplifier. What will not work is something like Wilson Audio or B&W speakers, with low efficiency, a band split into three or more drivers,... | |
| 300b lovers What separates the Euro super tubes is massively higher electron emission. For example, what separates the EML 320B XLS from the EML 300B XLS is 50% greater heater current, with correspondingly higher emission. But even the EML 300B XLS, although ... | |
| 300b lovers The operating points are conventional, well within standard 300B specs, with the plate at about 75% of max rating (which typically gives maximum life). But if you really want to slam the amplifier, well, you can. There’s nothing stopping you. The ... |