@lewm I have to say I'm amazed that you have had the continuing patience to deal with the 7241 power tubes! We don't modify any of our amplifiers to use that tube since most people don't have the patience to deal with them.
What is the “World’s Best Cartridge”?
I believe that a cartridge and a speaker, by far, contribute the most to SQ.
The two transducers in a system.
I bit the bulllet and bought a Lyra Atlas SL for $13K for my Woodsong Garrard 301 with Triplanar SE arm. I use a full function Atma-Sphere MP-1 preamp. My $60K front end. It is certainly, by far, the best I have owned. I read so many comments exclaiming that Lyra as among the best. I had to wait 6 months to get it. But the improvement over my excellent $3K Mayijima Shilabi was spectacular-putting it mildly.
I recently heard a demo of much more pricy system using a $25K cartridge. Seemed to be the most expensive cartridge made. Don’t recall the name.
For sure, the amount of detail was something I never heard. To hear a timpani sound like the real thing was incredible. And so much more!
This got me thinking of what could be possible with a different kind of cartridge than a moving coil. That is, a moving iron.
I have heard so much about the late Decca London Reference. A MI and a very different take from a MC. Could it be better? The World’s Best? No longer made.
However Grado has been making MI cartridges for decades. Even though they hold the patent for the MC. Recently, Grado came out with their assault on “The World’s Best”. At least their best effort. At $12K the Epoch 3. I bought one and have been using it now for about two weeks replacing my Lyra. There is no question that the Atlas SL is a fabulous cartridge. But the Epoch is even better. Overall, it’s SQ is the closest to real I have heard. To begin, putting the stylus down on the run in grove there is dead silence. As well as the groves between cuts. This silence is indicative of the purity of the music content. Everything I have read about it is true. IME, the comment of one reviewer, “The World’s Best”, may be true.
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I have one output tube located in the R front corner of on one monoblock that keeps failing in the red glow death mode. This has happened 3 times over the course of years. But of those 3 incidents, two have occurred in the last 6 months. Last time on the bench, I naturally checked the potentiometer that controls bias and the upstream bias voltage circuit and found no problems. Moreover, it worked for 6 months between then and now. Two nights ago, after a 90-minute listening session, I heard crackling on the R speaker and then saw that the tube in that R front position was glowing red. Plus the CCS tube for the input dual differential cascode stage was also glowing red. (Never saw that before.) If you have a genius idea how the input stage CCS could affect bias on only one of 4 output tubes (7241s), I am all ears. (My guess is these were unrelated events.) But otherwise, I have had no problems with 7241s per se. I bias them conservatively at 400mA each. As you know, my amps permit separate control of bias for each output tube, and maybe that’s why I in general do get away with using the 7241. Sound marvelous. I apologize for the off-topic post, but Ralph is my guru, and he did ask. |
@lewm , Good luck getting it straightened out. I am still waiting PATIENTLY for my MA 2s, but I did throw a monkey wrench into the works by asking for a 12 volt trigger on the amps. I think the newer amps bias automatically. I always keep a full set of tubes in reserve. Being neurotic, when one blows I'll change them all. Fortunately, the Seta L plus has a front panel gain switch as well as a switch to toggle back and forth between current and voltage mode. But, there is one issue that is a PITA. The flat signal has separate output jacks from the RIAA analog corrected signal. To switch back and forth requires getting at the back panel and moving the XLRs. This makes it more difficult to A/B digital and analog RIAA correction. |
@lewm It can't but I imagine you knew that. |
Ralph, thanks. Your corroborating my preliminary hypothesis will save time. Getting the very heavy chassis safely down to my basement workshop is my next problem. I’m hoping that the output tube in question was not damaged. Visual inspection shows that none of the 3 cathode wires is blown. That’s encouraging. There’s a problem in the bias circuit for that one position that’s going to be hard to find, because evidently I did not find it 6 months ago when the exact same problem occurred. Mijo, as I think you know, my amplifiers are essentially older MA2s with huge EI type power transformers that make them very heavy. I think you’ll be getting toroidal power transformers on your new MA2s. Much lighter. |
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