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Showing content with the highest reputation since 02/11/2020 in Posts

  1. 11 points
    I posted a Chinese version of this article several months ago and now I translated it and put it here. I guess some people here will be interested. I hope you like it. Actually I have some more articles like this pending but I just don't have the time to write it up. --------------------------------------------------------------------------------------------------------------------------------- It all started about a year ago that a second hand sr-omega popped up in the local community. From time to time omegas show up on markets around the world but this one is different: an omega with 007 drivers installed. When the drivers are replaced, such omega drops its value to a fraction of its original. The seller listed it for 48888 RMB initially and sold it for like 20000 + at the end. When I first saw the listing, the first thing that caught my attention are neither the price nor the 007 drivers but one accessory laying aside, which is a pair of dead drivers I have never seen before. At first sight I know that it’s a prototype, a true unicorn that probably only one pair exists in the world. I am so curious on how it sounds and how it compares to 007 or 009 or the original omega. I messaged the seller right away and after some persuasion and explanation that I can give this driver a next life, I got it at a reasonable price. And it has become one of my biggest regret that I didn’t also purchase the omega itself that time, otherwise I can put it back into the place where the drivers belong to. Here is the driver itself. From this driver you can see several innovations made by Stax that has never been seen in other Stax models before it. The diaphragm is identical to a normal omega but the electrode is totally a different creature: copper plate similar to lambda sig etc. but much more refined. Over different regions of the electrode the thickness is different. The thicker copper comprises of the # pattern skeleton to give the rigidity while the thinner copper is perforated. You can see the same topology on 009 and 009s where they claim to have the MLER welding technology employed on the electrode. But this omega prototype electrode is in one piece and just as thick as a credit card. Furthermore, they rounded the edge of the perforation like what Stax does on 009S. Stax even make a sectional view illustration graph on their 009S promotion leaflet. Such treatment helps sound to radiate. To me it’s really impressive to see some characteristics of a flagship model today on a 30-year-old design. I wonder what the R&D department has been doing in these years But afterall it’s a prototype. It does have some problems: this electrode is too thin to give enough rigidity and prevent bending. They are curved to 5 o at most. Moreover, the area of attachment between the frame and the electrode is too small. It just peels due to aging. I see such defects in some modern designs too. Although its reasonable to have these issues because its 20+ years old, it does reveal that the one who designed it is not thoughtful enough. Perhaps that’s why it was never released to the market except the one on my desk. Besides the defects the design has, the driver itself is at a very bad condition. The drivers have been exposed to the external environment, so dust gets onto everywhere. The one who does not properly seal the package probably has never imagined that this driver will be repaired. It’s a pain in the ass to make the driver dust free again, especially when they are on the very fragile diaphragm. Normally I don’t accept requests to repair an exposed driver and I will give a new quote to clients who send me an exposed e-stat without telling me in advance . But I own this driver and I can bear the risk so that’s OK. The four electrodes are bent in different direction and magnitude as well as having detachment and failure of epoxy. Taking it apart and bent it manually is the only way out. It takes a lot of skill to bend a bent copper plate. Like you have to apply a certain amount of force on the copper and then you check how you have bent it by eye balling or a ruler, and you repeat this process a dozen times on one plate. You make it worse if you don’t know how. The most challenging part of it is that how much you bend an electrode actually affects the sound pressure on one side of the driver so at this point you just have to guess. I have neither the tool nor the file of the design, its all hiding in somewhere inside Stax’s archive library. At most of the time repairing a e-stat is more challenging and troublesome than making a new one. Aging will just make everything a mess and sometime you have to wipe the ass of someone who does not make the design good enough to withstand usage. Solvent removes dust and grease on the driver. It gets much trickier when it comes to cleaning the diaphragm. Effectiveness of a method to clean the diaphragm is an issue when there is just too much dust, not to mention the risk that you will break a diaphragm by puncture or sketch. At the end I decided to clean the diaphragm with solution. Although it will damage the coating, it means nothing to me as I can recoat it anyway to replace the old one which is probably damaged anyway. Cleaning done. They took away the dust screens so I have to prepare these as well. Last Step: assembly, the most important part of all steps. This several hours of work determines how long a driver can last before imbalance or noise occurs. Its my duty to make sure every edge and surface inside the driver is dust free. If not, dust will eventually get onto the diaphragm at some point in its service life and short the electrode and the diaphragm. Practically if the pollutant is much smaller than DS gap 0.5mm then its fine. All these procedures are done in a dust free environment. Soldering work Omega adopted a spring mechanism to connect the bias supply to the diaphragm. It is shaped like a tuning fork and it is odd (photo credits to audiohobby .pl ). I tried to make one but it just can’t grip firmly. After some days of having this troubling me I figured out a way, using HD600’s spring and I glad that it worked, at least for now. I used 007 cable, lambda sig headband, cnc machined and anodized aluminum casing and tailor made earpad. I am a proud Omega owner and I shipped the earpad for a clone. The result is satisfactory. I took away the back grill for inspection but I am kind of regret because I cannot put it back. The general sound signature of this omega prototype is somewhat identical to the original: natural, airy, transparent and clean. Its free of unnaturalness which can be found on 009 (please forgive me if you find this statement irritating, afterall the perception of sound is subjective). It has a larger soundstage than 009 for sure but I think 009 has more details than this one slightly. To me this prototype takes a midway approach between early-SN omega and Late-SN omega. It has a bit of the sweet coloration of an early omega while having much of the naturalness of a late omega. I found that early omega has a huge, diffused soundstage while a late omega has some in head effect which is unpleasant to me. Luckily this prototype is more on the early side. But still this prototype is different from the two regrading the proportion of width and depth of soundstage. I can’t explain more because I haven’t AB compare yet. What amaze me the most is how the prototype omega differs from the typical omega in the dynamic and bass region. The normal omega gives me an image of mellow, soft and relaxing in the bass region. Although 009 and 007 has better bass and impact I like the stress-free presentation of the original omega. The only thing omega put stress on me while I am wearing it is its price. In the prototype omega, I feel an enhancement on the impact, the speed and the amount of bass. Perhaps it’s the reason why they create this prototype, to improve on what the original is lacking. The density of imaging of sound also improves by a bit. Be caution that I cannot remove the effect of the different earpad and casing on the overall sound comparing to the original so the effect I mentioned above might be due to them. Despite all these merits, there is something lacking in this prototype: The openness of soundstage and the super-revealing details on the original omega. If omega scores 100 and 009 scores 85 in the aspect, I will give a 95 to this prototype. The transition from mesh electrode to plate electrode seems to be a double-sided sword. I remember in one of the Stax staff interviews they explained on Pros and Cons between mesh and plate electrodes. You give up something to exchange for another. Nothing is perfect unless you pay a double.
  2. 10 points
    I work in an office in a building where there are also 3 or 4 other companies. Yesterday, our doorbell rings. The people who normally answer were out in a group meeting, so I and one other went to the door, to find a flower delivery man. My colleague is saying that the name doesn't sound familiar as I'm walking up. But he's newer, and may not know everyone, so I ask the name. Flower man tells me, and I say, "Hmmmm, not here, but I actually used to work with someone by that name....." [though it was a different spelling for first name]. Anyway, flower man checks one other company on our floor, not there....so I decide to help, and check it out on LinkedIn. Ah, OK, she works in the company downstairs....and then, I realize it IS my old colleague (and I had the spelling of her first name, Stacey, with no "e" in my mind)! So I went down to see her, but she was stuck in meetings. She contacted me online, we'll get together next week.... Haven't worked with her since 2002/2003, and then last saw her maybe 2.5 years ago at a concert during a Summer Folk Festival in Lowell MA.....and I find out she's been working on the floor below me for over a year! Small fucking world......
  3. 10 points
    Parenthood. "The sub was rattling."
  4. 8 points
  5. 8 points
    Took Mary and Lance to the airport at 3 am for their flight to Columbus OH. This will be Lance's last Junior Olympics. It has been a good ride all these years but the next phase of his life is about to begin. 🤨 A season of "last's" tournament wise. Hopefully this one will bring great memories and a whole lot of fun as national points and standings do not matter at this point. Glad I have a place here to unload because fencing is stressful...for the parents. Hah!
  6. 8 points
    Hey all, as a follow-up on my posts, Aumkar and team sent me a new headband assembly; just received today and it looks much nicer!
  7. 7 points
    Thirty years ago today, Carl Sagan showed images of the earth from 4 billion miles taken from Voyager: the "Pale blue dot" He said: "Look again at 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."
  8. 6 points
  9. 6 points
    Left to right: 404, L700 and 507 Sigma The one with 404 driver is more laid back and has more colouring while the 507 one has the best transparancy . But the L700 sigma is the best with a very full bodied mid bass and excellent 3D- imaging and soundstage I have never heard of in any other headphones. Love all three of them
  10. 6 points
    Friday - Bake Day for Sonja - Week 4 of Test Bakes for tafoni bakehouse -- getting closer - 4x4 different loaves. Still have paperwork and website work to go - and then setup equipment for the farmers markets.... inching closer. the breads --- Farmers flour from Cairnspring Mills: 67% sifted Yecora Rojo wheat 18% whole-grain Expresso wheat berries from Cairnspring Mills (home-smoked & milled): 15% smoked Gazelle rye with honey, black pepper, and chocolate rye malt Smoky Mocha flour from Cairnspring Mills: 67% sifted Yecora Rojo wheat 18% whole-grain Expresso wheat berries from Cairnspring Mills (home-smoked & milled): 15% smoked Gazelle rye with honey, espresso, and chocolate chips Rustic Rosemary all flour from Cairnspring Mills: 80% sifted Yecora Rojo wheat 20% whole-grain Expresso wheat enriched with honey and oil, flavored with rosemary Yecora Rojo Sourdough flour from Cairnspring Mills: 80% sifted Yecora Rojo wheat berries from Cairnspring Mills (home-milled): 20% whole-grain Yecora Rojo wheat
  11. 6 points
    My mini T2 amp boards. Note the screw terminals on the top to make troubleshooting easier I know JoaMat does not believe in screw terminals but I do. 😉. If you are careful its even possible to orientate the terminals so the silkscreen voltage markings are still visible 🙂 . I take a 2 terminal and cut it in half and put the original smooth side parallel to the silkscreen markings. There is not space for screw terminals for the heaters of the el34s so I (possibly temporarily) have soldered in a header pin at 45 dgrees I have used nylon m3 standoffs for the first layer so that there is no chance of the standoff shorting against anything and brass standoffs for the remaining layers to get to the required height. SMD soldering was done in a three step process. 1 apply solder paste to the pads. 2. melt the solder using a hakko 888D station at 330 degree C using a fine tip until the paste has migrated to only be on the pads. 3 Hold the component with twisers onto the pads and with my other hand use a Quick 861DA hot air station using the smallest supplied nozzle with airflow setting all the way down to 5 (even then its possible to send one of the small diodes into orbit with that air flow)... to reflow the solder onto the component. the reason I soldered this way was, 1. I could collect any excess solder with the hakko, since I dont have an electronic solder paste dispenser... 😞 2. I could be reasonably certain there was no solder paste left under a component. I use the same method for soldering Kevins' synchronous rectifiers. this is the schematic of the v0.2 pcb with valves from the silkscreen. The red components have changed since the last published schematic.
  12. 6 points
    I will be getting both sets of pads and naturally... I take everything apart so expect pics. 🙂 No doubt the normal bias SR-X is a bit bright as they were tuned like that. Stax wanted to bleed off a lot of the bass so the end result is a bright set. My point was more with the importance of the pads as they matter a lot with the close proximity of the drivers. Also when they have arc'ed...they get even brighter.
  13. 6 points
    Today’s mini project. Timer 555 with a few other components. When IN (the empty pad just below left leg of the two color LED) is low then RED, if high then GREEN. Standby/On indicator.
  14. 6 points
    Seems like a good day to start a biography of Pliny the Elder and Younger that Claire got for me at Christmas.
  15. 5 points
    Intention is to have updated schematic and BOM at just on place to avoid different versions floating around. This place is the first post of this thread. The advantage is that I, as the disorganized person I’m, cant publish schematic or BOM whenever I feel for it. I need Michaels (mwl168) approval and he is the only one that can make changes public – in the first post of this thread. Anyhow, please take look at the new files for errors or other issues. Below are 3D prints of the new layouts (them I'm authorized to publish myself) Please check for errors. I appreciate feedback especially regarding silkscreen, if anything seems unclear, let me know. Changes: Some resistors value. Offset balance op amp: OPA197, hopefully more reliable. Balance servo op amp: LF356, is more similar to LF353 in the DIY T2. OP27 seems to be reliable in this position though.
  16. 5 points
    Actually, since the speakers aren’t wearing their grills... Sent from my iPhone using Tapatalk
  17. 5 points
  18. 5 points
  19. 4 points
    Speaker porn? Amplifier porn? Lots of porn.
  20. 4 points
    Given The choice's We decided to share Biscuit Sandwich ( with mmmmmm bacon gravy on the side And the grilled cheese Benedict ( hollandaise on the side) Both excellent. Pity you lot weren't here as they have my kind of sharing!
  21. 4 points
    Archie Shepp & Horace Parlan - Trouble in Mind
  22. 4 points
    At the Close of a Century – Stevie Wonder
  23. 4 points
  24. 4 points
    The bolt was OK, the wire though was broken. Maybe the bolt damage the wire when it was tightened. Anyhow I got the opportunity to see how the RR 1 is built. I also disassembled the driver unit. Spacers seem to be about 1.3 mm thick and the sound when knocking the diaphragm it sounded about right. And yes, everything is easily accessible, except the pads maybe. Bottom line: I like the design. P.S. As the original pads were removed I took a pair of 007 pads
  25. 4 points
  26. 3 points
    It is only 48 outside, but clear. So two open faced burgers on the grill. Sonja got two as well.
  27. 3 points
  28. 3 points
    I am not picky. I like them both!
  29. 3 points
    @jamesmking is the heater from pin 7 on el34 connected correctly on your schematic? Seems that it's connected to the junction of r28/29 on the original schematic?
  30. 3 points
    Yes, JBL 4312G Although I prefer another component of that equipment….
  31. 3 points
    So that's how they make ambient music. Now I get it.
  32. 3 points
    ^^^ Those need the orange grills to match her dress.....
  33. 3 points
    Met my former college roommate and his kids for breakfast this morning before work. In my memory college doesn't seem that long ago but it has already been 13 years since we graduated in '07. Time sure does fly!
  34. 3 points
    With the SR-X series the pads make or break them. The current pads Stax stock are actually SR-30 units as the originals haven't been available for a long time. Now for the topic at hand, I have one of these incoming so it will be fun to play with. 🙂
  35. 3 points
  36. 3 points
  37. 3 points
    Talking heads and Wham! - it is the music that makes the system...
  38. 3 points
    Younger 2020 with Stretch and TMoney. First time in Windsor. In the first wave, happily.
  39. 3 points
  40. 2 points
  41. 2 points
  42. 2 points
  43. 2 points
    The above makes me want to watch this ...
  44. 2 points
    Remember this? I re-watched it for the first time in years. I was fine until the crane. Then I was palms sweaty, mom's spaghetti.
  45. 2 points
    I don't need a 7.1 MacPro! I don't need a 7.1 MacPro! I don't...
  46. 2 points
    Removed head band and it looks like this. I suspect it will break, probably sooner than later, so I took some of my wife’s elastic band and replaced the original band. I’m using same elastic band with my two kitchen made headphones and I’ve found the elastics quite comfortable.
  47. 2 points
  48. 2 points
    Friend of mine just picked up a $7,000 door stop.
  49. 2 points
    Just for perspective, every time you walk across a carpet on a dry day, and touch your hand to a doorknob getting a little electric shock you are discharging a kilovolt or two of static electricity. .
  50. 2 points
    Thanks everyone. I did in fact enjoy buying myself tons of gifts. Nice change up from the normal days when I just buy myself tons of stuff.
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