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Showing content with the highest reputation on 06/13/2017 in all areas

  1. I published a modification for the Stax SRM-T1/T1S/006 in AudioXpress July 2017, which is just out. The modification adds 5.1 kilohm output safety resistors and cascoded constant current output loads, which with their heatsink fits the space vacated by the plate resistors - see photo. Spritzer did something similar a few years ago with an SRM-007, adding constant current loads, but he also changed to 6S4A outputs. Unlike plate resistors, constant current loads burn up practically no signal current, so while the stock amp burns up 9.2 mA signal current in the plate and feedback resistors at its specified 300 VRMS maximum output, the modified amplifier only uses 2.8 mA driving the feedback resistors, leaving much more current available to drive the headphones. Since the output tubes are much less stressed, distortion is decreased and 2 dB of extra headroom gained. The modified amp circuit is very similar to a KGST or KGDT. This is no accident, as the KGST was designed to be “a Stax SRM-007t with no cost or retail considerations,” and the 007t is a higher power T1. The modification lacks the KGST’s regulated power supply, but larger power supply caps have been fitted. Since the amplifier is fully differential pure class A with current sources or loads at every stage, the current draw is pretty constant, minimizing power supply effects. The modified T1 can drive demanding headphones like the SR-007 Mk I, something that the stock design strains to do. The relatively flabby bass, somewhat dark tonality and soft treble are largely eliminated. Replacing all the old electrolytic power supply caps should also be done as routine maintenance. Parts cost for the modification is about $35, so total parts cost is around $100. With T1 amplifiers going for $400-$700, this is the best bang for the buck, a good starter project for someone wanting to get into electrostatic amp DIY without going to a full build.
    8 points
  2. Turning an old capacitive terminal keyboard from 1978 into a modern USB keyboard with fully programmable keys. Got it working fine, but had to tear it back down for keycap polishing and a few minor tweaks. Currently reapplying dielectric lube to all the key stems. Need to finish up this project so I get back to testing Circlotron stuff.
    7 points
  3. Never mind the wiring rats' nest for now, it's making music! The problem I was having with one channel, worked out to be a cold solder joint on the global NFB resistor network on one tube. Was distorting the voltage (off by 10V) on its pzta56/lsk389 half and throwing the balance and offset WAY off. Once found and corrected, both channels are stable as a rock (while running 30 minutes) without the servo engaged. Under 1 volt balance and offset both channels. First listened with my SR-207 then my SR-009 (with a lousy iPhone 6 Plus as source). Using 2000 vintage SED Winged C EL34s at 20mA. Damn, this amp kicks major ass! Now time to mount the transformers, clean up the wiring and build the umbilical, wire up the bi-color power switch, replace the 12V zeners with 18V ones, get the RK50 somehow mounted in to the case, and button it all up. Will post glamour shots when done. Thank you Kevin for such an incredible 'stat amp. I'm really going to love this over my KGST.
    4 points
  4. We did it guys! Wooooooo! This is by far the best moment of my 10 days as a diehard Warriors fan.
    4 points
  5. Went to Davies ( probably my last time in a while) and listened to the SF Symphony with Susanna Malkki conduct the Rite of Spring yesterday. Holy god this woman can strike a dynamic reading and she's a total blast to watch too! 10th row and a tad to the right had my trouser legs flapping and my face 'a grinnin'. This was just my second time attending what is one of my top 10 orchestra pieces of all time. I'll never forget it! If you get a chance to see this gal, don't miss it! http://susannamalkki.com/
    3 points
  6. Oh yes. Good lord, 120hz on a tablet feels do damn good. This thing is a monster.
    2 points
  7. I'm 60 and don't feel my age. I credit having kids.
    2 points
  8. When you're going downhill, you pick up speed.
    2 points
  9. I have the sweet home recommended duxtop and do not use my coil stove at all. Yuge upgrade.
    2 points
  10. Good lord NO! Abe's has been a train wreck for as long as I can remember. I think the right choice at this point is to get something that'll work for the first year or so and upgrade when budget permits.
    2 points
  11. It's always time to go custom. Sent from my SAMSUNG-SM-G890A using Tapatalk
    2 points
  12. That sounds like a neat concert to see! The Rite is a blast to play as well I wonder if my friend was having fun playing it (bass trombone)? Sent from my iPhone using Tapatalk
    1 point
  13. Bah, was holding off on biscuits to help out Chris (but don't tell him that) and was elated to see what I thought was a cracked screen. Alas. Enjoy the new toy; maybe PUBG will come out with a GRW-esque companion app for you. **BRENT**
    1 point
  14. Agree, Cleveland did not embarrass themselves. They played hard and gave it their best shot. I lost interest in basketball years ago when the Lakers were winning it every year. It got boring. Fortunately, I live in the bay area which is probably the only reason I'm into it now. So, band wagon here too. The deck is stacked and looks like it will be for years to come which sucks for everybody else. That can't be bad for basketball in general can it?
    1 point
  15. 1 point
  16. At 60 the drop-off is severe. You realise that gravity is not just a nuisance, but a force to be reckoned with. Yep, the only jumping you can do is jumping to conclusions....... else it leads to concussions........
    1 point
  17. I guess I'm a bandwagoner, but I've been rooting for GS for many years. They play the unselfish small-ball that I love. the Cavs, with Lebron and, especially, Irving, epitomize the kind of selfish ball that was so prevalent in the 90s, that I hate.
    1 point
  18. Steam-punk retro-cool for the win....
    1 point
  19. Congrats KD, though I sure wish you'd been wearing an OKC jersey when you got it done. And congrats warrior fans, of course. Watching LeBron walking off was interesting... He's said he has nothing more to prove and he looks the part more than ever. I hope everyone hating him these last 5-6 years wakes up before he's done because this is the second time he lost a finals and should be series mvp. Unbelievable stuff.
    1 point
  20. Saddle is great. The thick ass seat post is typically the first thing ripped off of Litespeed bikes as the shitty MTB seatpost is massively stiff. I rode a shop bike that had the same frame but smaller CF seatpost and the difference was immediately noticeable. Just that extra bit of compliance is enough to notice, even though my saddle is more comfortable for me than what was on the shop bike, it was a much better ride. The reason for the massive hoods is the fantastic hydro brakes which make me never want to road a bike with old fashioned brakes again.
    1 point
  21. Meanwhile ... http://www.digitalspy.com/tv/luther/news/a830572/luther-series-5-idris-elba-returns-four-new-episodes/
    1 point
  22. Oh yeah, Brent, I found a bike computer for you.
    1 point
  23. https://www.engadget.com/2017/06/12/sharp-sues-hisense-us-tvs/ Apparently Hisense is why new sharp tvs are garbage
    1 point
  24. Gravenhurst – The Ghost In Daylight
    1 point
  25. Went out for a quick spin on the MTB today on the trails behind my house. A neighbor pointed me to a new section, which is a hoot. Good news is that the test of the 1x10 conversion that I had done last week went without a hitch.
    1 point
  26. Need to call it because the rest of the install will happen in the meantime and speaker placement depends on the dimensions of the set. Going with ribbon tweeter Monitor Audio in-wall LCRs and two Triad in-wall subs. Will look something like this ... Surround channels will go back to the existing in-ceiling speakers, which isn't ideal but does keep everything clean in what is more a living space than a dedicated media room. Should be pretty sweet.
    1 point
  27. 1 point
  28. Mmmmmm.....new London Grammar.......Truth Is A Beautiful Thing
    1 point
  29. A great anecdote in the paper about Douglas Bader, the double-amputee English WWII fighter ace.
    1 point
  30. I'm currently picturing all the animated discussions of this issue taking place across the Internet.
    1 point
  31. Milled a couple of small board 0.8 x 1.15 in. Put a cheap USB microscope on CNC machine. Easy to move microscope over the board. Took this picture, optical magnification x40.
    1 point
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