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Showing content with the highest reputation on 04/06/2022 in all areas

  1. Karen is out of town and Peter is hanging with his girlfriend so decided to check out a local seafood market/restaurant. They specialize in fresh, locally sourced seafood so everything below uses fresh, local seafood. Started with a dozen raw oysters since they are my favorite Followed by a bowl of their blue crab gumbo with a main entree of grilled grouper with hush puppies, Cuban black beans and coleslaw for desert I had key lime pie and a cup of coffee (no picture because the second Tiki drink was catching up to me - See Drinking Thread)
    5 points
  2. Now we are talk'in 😉. The tube channel has become really close to the SiC FET channel, both at 100V output. The performance is not yet at the Carbon level, but is pretty good for a tube amp. What was the problem with the previous mod? The simplified G2 supply didn't work well. This tube is quite sensitive to Vg2 (which may make it a good candidate for G2-drive applications, given the low Ig2). The previous circuit has Vg1 as part of Vg2, so the Vg1 variations causes Vg2 changes. The solution is to use one 150V zener diode for each tube, put it across G2 and K, and feed <1mA of current from GND using a resistor or a current source. I also added a 10uF capacitor in parallel with the zener. Without it, the output clips at around 300V but the distortion still looks good before the clipping. Now the circuit should deserve an audition. Since the main problem is the knee on the Ia curve and Ig2 curve below Va=100V, with higher B- (500V maybe?) and perhaps higher current, the tube circuit should perform even better. I'll leave that to the next episode. For now I'm waiting for the sockets from China to build the other channel.
    4 points
  3. Was listening to Queen's 1977 album News of the World and reflecting on its cover art. The cover art was done by Kelly Freas, based on his cover for the October 1953 issue of Astounding Science Fiction. There's an alternative cover for NotW, which was also inside the gatefold on some versions: Freas' artwork is kind of creepy, unsettling, quite vintage looking but also weirdly futuristic. I remember seeing it as a kid and not being sure what to make of it. The music is pretty spectacular as well.
    3 points
  4. Recently, I became a member of the Board of Directors of the Communities of Belonging Organization. We strive to help marginalized individuals get the resources they need to persevere and re-enter society successfully. https://communitiesofbelonging.org/ As a part of April being 2nd Chance Month, we are holding a walk to raise awareness and funds to support our vision. We will be walking around Green Lake in Northern Seattle (for any locals in the area). If you would like to be a sponsor, I have setup a team on our Givebutter site. Please take a look. https://givebutter.com/XXcbAZ/michaelmaddock Please feel free to ping me with any questions and thanks for everything. Cheers, Mikey
    2 points
  5. 2 points
  6. It's doing really good. I'm guessing another few weeks and I can lose the bandage.
    2 points
  7. The saga of messing with my 2nd Carbon build continues. Since the circuit is very close to the Grounded Grid, I'd like to give it a try. Being hesitant to spend big bucks on a nice quad EL34, I have been on the lookouts for a cheaper substitute. The curve of a pentode looks a lot like that of a SiC FET. I need a pentode with the following properties: The plate curve should have low kinks or no kinks at the low Va range. The lower the 'knee' the better. Low Ig2. Ig2 should be much smaller than Ia (20mA), ideally 1mA or less under the operational Va range such that Ig2 doesn't interfere with cathode drive/ cathode degeneration. The amount of negative bias needed to get 20mA at 400V should be reasonably easy to handle. High rated Va(max) and Pa(max) for using a higher supply voltage and/or idle current in the future. That means I may need to look into transmitting tubes. And the candidate is... (drum roll please) the FU-50/GU-50! The linearity looks pretty good at around Ia=20mA, from Va=100V all the way to 1kV! The bias voltage is between -20V and -25V, right around what Carbon has. The Ig2 is really low and changes very little from Va=100V to 1kV. More importantly, the FU-50/GU-50 are relatively inexpensive and plentiful. A lot of them were made in the USSR and China during the cold war era. I read somewhere that those were designed for the comm gear used in the tanks and had very little success in commercial applications. I paid less than $3 a pop from Ukraine about 15 year ago. The going price for a NOS tube should be close to a SiC FET today. Well, any tube not designed for audio can be cheap these days. However, that wouldn't stop people from chasing after the Telefunken LS50 and the east-Germany SRS-552s, I guess 😉 Adapting those to the Carbon is surprisingly easy. I removed the SiC FETs and the 20k bias resistor, replaced the two 175k resistors with a 100V and a 130V 3W zener diode for G2 supply. The Ig2 is really small and the two tubes can share one set of the zener diodes. They drop 230V from GND and set Vg2 right at 150V, with about 22V left for the PZTA42 and the offset pot. The heaters are powered by a 12.6V filament trans with one side tied to B-. I could have tied the CT but there was very little hum to worry about. Guess what, the GU-50s work right out of the box. I didn't even need to adjust the balance and offset! The measured performance is pretty decent: Although the distortion is low, the FFT does show some higher order 'pentode nastiness'. I guess the reasons being The pentode is not super linear to begin with. The transconductance of the GU50 is about 1/10th of the SiC FET. The PZT42 has to work much harder and the global NFB is less effective. Something else worth looking into I'm not yet able to seriously listen to the sound, because I couldn't find another pair of tube sockets in my stash for the second channel 😂. If you want to know how it sounds, try it! The GU50 with 400V PSU comfortably beats the KGST (below) on the frequency response and the output swing: Next to try is to use the pentodes on the KGST, or should I call it KGSP then?
    1 point
  8. Billy Bragg's The Million Things That Never Happened Ex.
    1 point
  9. I don't listen to a lot of classical vocal other than full opera and some live performances. But I really liked this one. Mirages Sabine Devieilhe 2017 https://album.link/us/i/1291109280 One of the reasons I like this is in no small part because of:
    1 point
  10. Done....read up on it a bit, nice cause!
    1 point
  11. In spite of my considerable reservations as to his character, it turns out that the current on hiatus status of The Grand Tour has left me wanting more freakishly tall British jackassery in my life so when the Prive Video splash page (bless its heart) suggested this to me last night: I started watching. True to form, Jeremy is bad at everything. Also this show was filed right before Covid started, which certainly gives it a vintage feel. It's like watching pre-9/11 films in 2002.
    1 point
  12. 1 point
  13. Russia Threatens Wikipedia With $50K Fine for Ignoring Ukraine Warning. 🤡
    1 point
  14. The Grammy's appear to work ( as marketing) ...
    1 point
  15. So, I am good with my four OPA445. Thanks, Kevin for confirming.
    1 point
  16. I've posted this before, but Carl Sagan's commentary is worth repeating here. The image is called Pale Blue Dot, and was taken by Voyager 1 from about the same distance Neptune (6 billion km). Although the Earth is clearly blue, it is actually only 0.12 of a pixel in Voyager's camera. "From this distant vantage point, the Earth might not seem of any particular interest. But for us, it's different. Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam. The Earth is a very small stage in a vast cosmic arena. Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot. Think of the endless cruelties visited by the inhabitants of one corner of this pixel on the scarcely distinguishable inhabitants of some other corner, how frequent their misunderstandings, how eager they are to kill one another, how fervent their hatreds. Our posturings, our imagined self-importance, the delusion that we have some privileged position in the Universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves. The Earth is the only world known so far to harbor life. There is nowhere else, at least in the near future, to which our species could migrate. Visit, yes. Settle, not yet. Like it or not, for the moment the Earth is where we make our stand. It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known."
    1 point
  17. I am wandering when people here assambled T2 and use it with Alps RK50 potentiometer from past age. Some years ago I inverstigated question about volume controls. Looked even on Bridged-T attenuator: https://www.electronics-tutorials.ws/attenuators/bridged-t-attenuator.html And as a conclusion: best attenuators are transformer TVCs. Until some music level resistors (even z-foil) is the best. But for Ultra HiEnd is TVC. In attachments is mine. FR @1kHz=0db almost flat up to 1MGHz. It is better then Stevens and Billington TX-102 TVC, Music First Audio - Passive Magnetic Preamplifier and so on. Even this not the toppest one, but it is very very pleasent for hears.
    1 point
  18. Oh man, I've been putting off writing this one. I have 3 uncles, all on my mother's side. The youngest is a really good dude who has been tasked with dealing with the aftermath of the bad actions of other family members for his entire life. The oldest is an unimaginable piece of shit even by the standards of trash tier relatives. I would not micturate on him were he on fire. Sadly, he lives on at the age of 82, showing no signs of slowing down. My third uncle, the middle one, was born retarded. He spent some troubled times in the 1960s and 1970s in "state schools" which were horrible institutions in MA where all sorts of people with mental disabilities were dumped. In those places my uncle experienced horrors we shall never know. He was never verbal beforehand and was even less so after. From family stories I know he was attacked by aggressive "patients" (not really an appropriate term, but it's what they used) and was more or less defenseless. He'd show his trauma and pain by biting his own hands and the staff would notice the wounds. How long this went on I cannot say, but it was a time period measured in years. In the 1980s, he got out of the ellscape that the MA institutional system and into much more caring group homes. In the 1990s, he moved in with a family who were paid by the state to take care of him. Mercifully, they were a very caring group and took care of him quite well. Late last year the matriarch of that family contacted my youngest uncle (the good one) and said they could no longer really take care of my retarded uncle. That lead to a series bureaucratic headaches where my uncle eventually ended up back in MA institution. Fortunately they aren't as bad as they once were. Not too long after, my uncle contracted Covid. He recovered, but he was 63 years old and not in great shape. He was in and out of the hospital, most recently being treated for intestinal blockage. He returned to the institution and died hours later. His passing has been very hard on his surviving siblings (minus the asshole one, whose opinion to me on par with that one Mr. Putin.) I think for my uncle it was a mercy. What I observed of my uncle was that in spite of the horrors he experienced and witnessed, and his inability to communicate his suffering to anyone around him, he was an an amazingly sweet guy. His limited expressions showed shyness, curiosity, good nature, humor and a kindness I seldom see in us "normal" people. I tried to draw some inspiration from his kind spirit and find strength in his ability to rebound from trauma.
    0 points
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