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Showing content with the highest reputation since 05/12/2022 in Posts

  1. I was going to name it 'Double the Carbon, double the voltage, double the fun', but I'm afraid that would be too wordy. Ever since I measured the output swing capability of the Carbon, I wanted to see if it can drive my ESL speakers. To do that, I'd need a beefed-up version that can output at least 1kVrms before clipping. That's 1414V peak, out of a ±750V to ±800V PSU. To simply scale up the Carbon amp and the GRHV PSU without major changes to the PCBs, a few hurdles would have to be overcome. First is the 900-V rated 10M90s in the cascode CCS that bottom out with ±450V PSU. When I was browsing the high voltage FETs at Mouser, I found the UnitedSiC UF3N170400B. It's a 1700V 6.8A SiC JFET, naturally in depletion mode, perfect for the upper device in the cascode CCS. The threshold is about 9V, which helps the DN2540 to get further into the constant current region yet keeps the power dissipation still in check (no heat sink needed even with the TO-92 package). The drawback is the package. The TO268-7 isn't too friendly for a DIY thermal solution. I had a few carrier boards made with aluminum-based PCB. According to simulation, the little board would give me 9 degree temperature difference from the package case to bottom of the board when the FET is dissipating 9W. I chose black solder mask, hoping to get a bit better heat radiation capability. 10 boards cost me about $3 at JLC. They also have copper-based PCB with a special process to have the base copper flush with the top surface for a much, much higher K. Too bad the NRE is about $150, so I chose the cheaper route with aluminum. The insulation is good to 3kV so this board can be bolted directly on the main heat sink without additional insulation. Isn't that great? The next bottleneck is the 600-V rated STN9360 when the PSU voltage reaches ±600V. I replaced them with the 900-V rated 2SA1968s. Thanks to the cautionary words from spritzer, I started cleaning up traces with high voltage differential that are getting too close to each other. I removed the middle pad 'A' in the 10M90s footprint, and re-wired a couple of traces on the back. With the bias changed from 24V to 13V above B-, the JFET can be used as the output device as well. At almost $10 a pop, they are considerably more expensive than the SiC MOSFET they are replacing. So the full-JFET configuration shown below is more of a proof-of-concept than anything else. The feedback dividers are changed from 200k:200 ohm to 440K:470 Ohm to maintain the gain and allow the output swing to double, without having the feedback current overtaking the idle current through the input JFET. Two 10pf 1KV caps are in series as a 5pf cap, since I don't have the proper 2kV rated caps. Not a great idea. I was lucky it didn't blow up. Technically the board is now ready for up to ±850V. I tested the SiC-JFET 'doubled carbon' config with ±400V PSU. The performance is slightly worse than the original Carbon. Is it worth the effort? We'll see. (To be continued...)
    13 points
  2. Arrived yesterday and it really opens up every electrostatic headphone that I own. I was looking for an amp that can bring more bass out of my HE90 than HEV90 so I drained my pocket to bid on this and now I am very satisfied. The hev90 has a romantic sound but the t2 amplifies every piece of detail, expand the soundstage to what ever possible with extreme fineness and sweetness. Buying any head-fi gear at this price is ridiculous but considering the previous closing bid I think I got a fair deal. And it is so rare to have T2 being sold alone. I do not need another pair of omega so this deal saves me a lot of money. But this amp's functionality in long run is questionable. I hope my handful of obsolete FETs stock will save me some pain when I need to fix this in the future.
    10 points
  3. Went to see Wagner's opera Lohengrin last night at the Royal Opera House, Covent Garden, London. This was the final part of my awesome series of birthday presents - this one from my wife, long planned and two months afterwards. It was bloody awesome. Everything was perfect - the setting, the set and lighting, and an Internationally renowned top flight cast of singers. https://www.roh.org.uk/tickets-and-events/lohengrin-by-david-alden-details With various courses of an excellent meal in the intervals. Carole was not a Wagner fan initially - but I've converted her. She was in tears of emotion by the end of the overture to Act 1 (honestly - so was I!). Now Wagner the man was a loathsome individual. Anti semitic, hateful towards his contemporary composers, and impossible to work with - a micromanager from hell. He described Brahms as "That bastard, Brahms", and put it about that Brahms' music was inspired by shooting birds from his balcony with a "Tyrolean bow" (there is actually no such thing) and listening to their dying cries. His dreadful reputation was not helped by Hitler being a Wagner fan, and it representing the pinnacle of music for Nazi National Socialism. Putting the awfulness of Wagner to one side - he was one hell of a composer! You just have to divorce the man from the music.
    9 points
  4. i am really glad i didn't buy ls50 wireless in the past... very good chance i will try these at some point https://us.kef.com/wireless/ls60/ls60-wireless.html
    8 points
  5. Finished up the week at Milo & Otis siding, screen & vent repair, in preparation for what may be an epic paintjob on Mayberry Manor.
    8 points
  6. 7 points
  7. I just can't help it. There's something about him...
    7 points
  8. Take a breath and stop issuing orders when you are not empowered to do so. I see nothing wrong with the posts here.
    6 points
  9. I just cleared out a bunch of boxes of my momentos, family memorabilia, and files from my parents' house that had been in boxes in front of my main rig for many months. I decided to pick a Jeff Beck album (There & Back) from my high school years to celebrate clearing it away (sadly, just into the basement--sorry Marie Kondo). I still like it, but there is a whole lot of Jan Hammer on this album!
    6 points
  10. Nick Cave and Warren Ellis all morning. La Panthère Des Neiges/Carnage/Ghosteen.
    6 points
  11. Don't I know it. Still, so much death right next door influences every part of life. That is grammatically an imperative, so, an order. I have no fight with you, Helium, I'm just expressing a little solidarity with a fellow forum participant in my neighborhood. That can't possibly be what passes for hate.
    5 points
  12. Слава Україні, і удачі з Кишинева.
    5 points
  13. My pair just came in, I'll try to keep an open mind comparing it to the 007
    5 points
  14. I’m happy to hear you from you, @micon21 and I wish you and your country all the best in the fight with Mr. Putin. You will survive. In the end the good will defeat the evil.
    5 points
  15. Thanks all! I had a decent day and took it easy.
    4 points
  16. So I am having lunch with a Whisky buddy the other day and he mentions that he was listening to one of our whisky friends in Europe's album. Album? Lars' has an album, Lars is in a band? I have not met Lars in person yet, just international zoom meetings to talk about important stuff (like whisky). This is how I picture Lars (long beard) ... {and yes, I probably could name a lot of the whiskies by the back of the bottles} I looked him up on TIDAL - Hey there he is, now that is legit. So... This Boy Lars Nyborg 2020 https://album.link/i/1529237508 Example: He has a few actual videos as well, but it is distracting for me to see him sing. Overall, I enjoyed the album. I am biased because I know him. And how he does all that and be shitcanned on scotch, is beyond me.
    4 points
  17. Seems like the old IT trick worked.
    4 points
  18. Thank you mwl168 for the opportunity to get the mini T2 boards. the package from mwl168 arrived on february 22nd, and on the 24th my country was attacked by the enemy. and everything went into the background, the country was fighting for survival. thanks very much to many countries, especially the USA, very much helped and helped. now there is already hope that my country will survive, and i hope that i can solder a mini T2 and listen to the potential of this version. Translated with www.DeepL.com/Translator (free version)
    4 points
  19. I would have called you a cunt for your prissy comment and imperious demand, so n_maher and Sherwood have let you off lightly by Head-case standards. So take a breath or take a hike.
    3 points
  20. So a unitasker, then. "I have railed against unitaskers for 20 years. I've come around to liking them as strategic gifts for people you don't like." https://www.npr.org/sections/thesalt/2015/12/23/460833325/the-unitasker-kitchen-gadgets-alton-brown-loves-to-loathe
    3 points
  21. My GMT which I bought new in Jan 1990
    3 points
  22. I forget who said it, but someone in here mentioned they drive by the SmugMug HQ (the people who own Flickr) and that the bulding is a dump. Went on Google Maps and, uh, can confirm: https://goo.gl/maps/sYgVyvq8SHxQTSFH7
    2 points
  23. I've listened to several Joy Division things today, including some early material when they went by the name Warsaw. For several years they were my favorite band, and are still up there in the top 5..... Probably my favorite song by them is Decades, the last song on the Closer album. In hindsight, knowing of Ian's suicide, this is such a powerful song to me. There is a keyboard "solo" towards the end that just sounds so frail...and of course the lyrics are very fateful..... EDIT: and the first single that new Order had post-JD was Ceremony/In A Lonely Place. Written while they were still Joy Division....the B-side is also incredibly powerful lyrically and in mood. Again, especially in hindsight....and it was the last demo ever recorded by the group apparently Lyrics: Caressing the marble and stone Love that was special for one The waste in the fever and heat How I wish you were here with me now Body that curls in and dies Hardship that often belies Warm like a dog round your feet How I wish you were here with me now Hangman looks round as he waits Cord stretches tight then it breaks Someday we will die in your dreams How I wish we were here with you now
    2 points
  24. @skullguise mentioned elsewhere that today is the anniversary of Ian Curtis's death in 1980. RIP to the legend.
    2 points
  25. 2 points
  26. Someone Shot The Johnny Cash Water Tower In Kingsland, Arkansas, And Now It’s Taking A Leak.
    2 points
  27. I’ll be more than a little curious to get the hard-core (or semi hard core) audiophile opinion of how these work. If they work as advertised and as intended, my read is that they’ll basically replace about 90% of the standard audio chain. Have a nice preamp? Don’t really need it any more. Nice DAC? Nope, don’t need that either. Amp? Shit, what is the point of all those McIntosh lights anymore… Brave new world if they work.
    2 points
  28. 2 points
  29. Yeah, well... https://www.youtube.com/watch?v=kGi2AlMhraQ
    2 points
  30. Thanks for granting permission? You think you have conditions to the suggestion that you should go elsewhere? Your "if you are a man" bullshit is tiresome. If you think we're interested in your 1,000+ word missives about what you think, what you won't stand behind, what you will, etc., etc., ad nauseum, you are mistaken. No one asked you to join here or told we don't have a ToS because we don't need one.
    2 points
  31. sure. and i have 4 original esl63 transformers in stock. (2 transformers make a center tapped pair)
    2 points
  32. start with a megatron and change the 8 output tubes to 4cx250 then use +/- 3000v power supplies far more fun. and just a slight bit more dangerous.
    2 points
  33. Finished Severance over the weekend. Really enjoyed the mind-fuck of it all. I didn't do a lot of theorizing, so a lot of the reveals in the final episodes hit plenty hard, even if there were some bread crumbs leading up. Finished Slow Horses last night. Really enjoyed that too. I forgot how much I like the British 6-episode season. The story flew by, and never felt bloated like some of the "we have to get to 10" Netflix series can. And Gary Oldman is amazing. Looking forward to second seasons of both. Need to get back on The Great.
    2 points
  34. Egg, toast and potato cake from last night's left over mashed potatoes.
    2 points
  35. Counting down to the mornings excitement… https://www.nytimes.com/2022/05/12/science/black-hole-photo.html?referringSource=articleShare EDIT: Okay, maybe not the most exciting presentation. Better feed:
    2 points
  36. We have a cat named Jellybean It's also the name of Craig's cat on Malcolm in the Middle. and Marshmallow is the name of Dewey's dog
    2 points
  37. Piper started calling her Jelly Bean and it seems to have stuck. Integration is going pretty well. Nutella seems wary of another female, but Marshmallow seems to have accepted her quickly. They play together a lot and Lauren sent me this earlier today. I’m happy to call that a win. And even though she’s still getting settled, there clearly isn’t too much drama. from yesterday…
    2 points
  38. Some folks aren't understanding the difference between something being publicly accessible but still not "a public space." This is a MODERATED forum. Over the years it has established itself to have a certain personality, for lack of a better term; and it is moderated to fit that personality. Yes, it can be exclusionary, but only to people who argue excessively about the personality and try to change it. Otherwise, we want it to be open. When someone is banned, it's not us being cowards, it's reducing excess noise from someone who doesn't respect what this forum is about. There are a good number of very technically-inclined and experienced people here. They freely give advice to those who ask, some design their own equipment, and overall have earned the respect they get. I have seen countless cases of people posting pictures and getting some great advice about what is good and bad about a design. As a group, we DO listen to a lot of music. There are dedicated threads for this, but there are also many threads for other things as well; we're quite an eclectic bunch. When it comes to equipment, though, we're not going to ONLY judge based on sound. As I mentioned before, sound is on par with build quality in this forum, and even if something sounds good but has potential build issues, it will get called out. That is part of the personality of this forum. I will read and respect someone's thought on sound, but will also read and respect good technical input, brash or not. If something is built well and sounds good, it gets praised. Otherwise, it's open season for criticism (based on sound or build). Again....this is the personality of this forum. Accept it, join and try to have fun. Or leave. But if you keep fighting it, you will be banned - to reduce the noise.
    2 points
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