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Showing content with the highest reputation on 05/07/2021 in all areas

  1. good soldering technique and understanding what is going on when you solder: (a little wordy, somewhat dated and slow paced but the latter part of the video has lots of useful info). I heartily agree a good quality temperature adjustable soldering iron is essential and it will make soldering easier, more consistent and you will get better joints. Something along the lines of the hakko fx888d (although the use interface is horrible) that has descent power and is reliable and has repeatable temperatures. also good quality solder and good quality flux I would add a good quality multimeter, one that will not blow up in you hand if say by accident try to measure a 400V psu rail when the meter is in resistance mode... and yes I am speaking from experience here.... I was tired had already lecturer for 9 hours that day. its not cheap but I really like the brymen BM869s. - or one of the lower end models they seem to be very well made and robust. If the multimeter supports temperature probe(s) all the better for verify transistor case temperatures are not excessive etc. joe smith one you tube has done some excellent videos comparing and torturing multimeters for reliability and high voltage tolerance. for proper verification of stability, checking for clipping, etc a signal generator and scope are necessary. For a signal generator the bare minimum would be the analog output of a sound card on a pc and some software to generate sine waves, triangle and square. given the high voltage outputs and rails the scope needs to have switchable x1 and x10 probes (x10 is actually divide by 10 so you can get 400V down to a more manageable 40V). Scopes can be dangerous to use since the ground wire on the probes is actually earth referenced and is clipped to something in the circuit which is not at earth potential you get the possibility of a short to ground.... Some form of desordering to 1. fix mistakes, 2 make repairs. The cheap option is solderwick or a spring loaded desoldering pump. The far more expensive option is a desloldering station. For me using a soldering iron and solder wick has resulted in to many lifted tracks and is too slow and clumsy. something like this works well and is worth its weight in 2sj79s. There are many similar types out there. it is temperature controlled and has a vacuum pump to suck out the solder. For safety a variac is also very useful it allows you to slowly increase the voltage going into the psu so that if there is an issue it would hopefully manifest at lower voltages and hence reduce the collateral damage once you get more serious a transistor tester and identifier can be very useful especially to check for bad components or to post mortem when the "magic smoke comes out". It can also do small signal transistor and led matching. if you are going to do any surface mount soldering there are multiple ways to do it. fine tip soldering iron, hot air station, reflow oven. Magnification is useful - . The cheap ones can be really uncomfortable and can slide off your head easily but if your eyesight is not 20/20 I find them essential for surface mount and for generally inspecting joints etc. now some "luxury" items to make life easier etc The duoyi allows you to test high voltage zeners and also aids in detecting fake old stock transistors by providing non destructive transistor breakdown voltage testing. The instruction manual is crap and the sockets are junk. But with some modifications it works well. another luxury is an LCR meter - this can allow you to match capacitors and inductors and also can measure lower capacitances e.g. a few PF than a multimeter can manage. It can also measure the effective series resistance of caps and other parameters so you can compare caps and identify worn out caps in old equipment. super luxury items because you are addicted to building: distortion analyser super luxury? ultrasonic cleaner. flux residue can result in joints degrading over time and at the voltages some stax amps work at e.g. the T2 the residue can conduct and cause failures. super luxury: sometimes the provided gerbers are the wrong shape, don't fit your style and you wish you could change them. Sprint allows you to import gerbers, modify and re-export. Its relatively cheap. https://www.electronic-software-shop.com/lng/en/electronic-software/sprint-layout-60.html?language=en super luxury: sometimes you want to make your own schematics: https://www.electronic-software-shop.com/lng/en/electronic-software/splan-70.html super luxury: hands free thin probes for smd or when you don't have 3+ hands available. (The same company also sells hands free multimeter probes). disclaimer, all items shown here I own personally and use regularly. However, other builders may have their own favourites and peoples priorities and build styles vary. So these are suggestions and nothing more.
    4 points
  2. I remember those little, lightweight, plastic headphones with the Yellow foam earpads that were so different than any other headphones out there in the 70's. You could actually listen for hours without your ears sweating. They were definitely innovators. End of an era, but change is a constant.
    3 points
  3. 3 points
  4. I don't have either of the devices that James has (dy294 or the peak atlas dca75... wish I did), but I built an adapter for the Toshiba dual JFETs using a zig-zag socket, a piece of PCB board, and some thick diode leads. I'll try to post a pic later. This, in conjunction with James' mod with the clip leads, would make this easy.
    2 points
  5. cfa2 is balanced out only with a balanced input cfa3 is balanced out regardless of input. also some versions are ZF/SS
    2 points
  6. I've been super slow about everything lately. But I did just get a note this morning that the final piece I need shipped. So ask again on a week or so.
    2 points
  7. Absolutely! Provided your retirement last no longer than a week.
    1 point
  8. Yup....still got mine, and they lasted through my son's childhood for the road trips where he would watch movies.
    1 point
  9. "Do you remember, 21st night of Septermeber"
    1 point
  10. I’m out of town for a couple of days, but I see if I can post a picture of it when back home. Basically it just a piece of pcb, some three pin socket (green I think) and two wires.
    1 point
  11. Sennheiser Consumer busines has been sold: https://www.theverge.com/2021/5/7/22424367/sonova-buys-sennheiser-consumer-business-headphones-soundbars Blog post from Senn: https://en-us.sennheiser.com/newsroom/message-from-andreas-and-daniel-sennheiser-otoics
    1 point
  12. rather than create an adapter I soldered clip leads onto the pcb and ran the leads through the existing holes in the plastic case: The clips also allow me to use adapters for sot23 etc etc. (the same adapters I also use with my peak dca75 transistor tester and identifier)
    1 point
  13. Just go 2x CFA3 boards and 2x GRLV (on one or even two transformers). For the amp you do not need to separate the + and - per channel, so 2x CFA3 boards is more than good to go. No need to put the CFA3 boards in separate cases, if you want to separate the L and R channels, put an aluminium divider in the mid of the amp case and use per channel umbilical on the back (off separate GRLVs and transformers in the PSU case), so basically going strict dual mono in two chassis in total. That's already more than overkill. You can have the headphone protector as well (for dynamic headphones, stats don't need that) and eventually the ZF/SS selector (which I didn't do).
    1 point
  14. Nice post with YouTube video clips above, James. One tool I’ve found very useful is desoldering gun. I use DEN-ON SC7000Z. The first one I bought nine years ago and it still working. Last year I bought a second one. DEN-ON isn’t cheap but it’s very reliable and it’s said to be possible to get spare parts if needed. There are different tips available and with the 1.5 mm I’ve desoldered the small 9 pin Teflon tube holder with ease. Another good thing with the DEN-ON is hot air blowing. With hot air blowing I remove smd parts. A few days ago when doing 0402 parts soldering exercise I tested to remove a few 0402 parts and that worked great. Then I put the parts back – good exercise...
    1 point
  15. Depends on how tight the clearance is in the holes, if it's not super tight it'll be a pain because you waste a ton of wick but will come out without too much work. A cheaper socket with flat pins will be ez pz to get back out, while one with round pins that just barely fit, yeah that'll suck trying to get out with wick. I can't say that I've ever actually put a large component on the wrong side before though.
    1 point
  16. I agree a lot comes down to how much you are going to build and your budget... however sometimes solderwick cant cut it. I once soldered an octal socket on the wrong side of a 2mm 2oz copper board.... solderwick that out 😱 desoldering station to the rescue, board and socket survived. the socket was ptfe round pin with tight pcb holes. 😬
    1 point
  17. This may be a matter of technique because I've had very little trouble using a wick to desolder components. It only really gets tricky when a pin is attached to a ground plane or similar, but if it's just one pin that will rapidly sink heat like that, it's no big deal since you can just do it last.
    1 point
  18. Love it, I'll be in touch.
    1 point
  19. The Canadians are at it too https://www.bbc.co.uk/news/world-us-canada-40124476
    1 point
  20. Last night I ate Detroit style pizza and plan to do it again soon.
    1 point
  21. Last night I made Detroit style pizza and plan to do it again soon!
    1 point
  22. As with most lists the order is all fucked up, but a lot of gems next time you’re looking for something to watch. https://www.rollingstone.com/tv/tv-lists/best-tv-sitcoms-1162237/schitts-creek-2015-2020-1163263/
    1 point
  23. hi! i would like to share my work with you. i am working on a small susy dynalo but with grlv psu and much better cooling capacity. also i will change the pzta tranzistors with toshiba 2sc2881 and 2sa1201 because they do not heat as much as pzta for some reason, and they are smaller (sot 89). it is a work in progress. for now i only developed an amp (one channel) and psu section without anything else. in following pictures you can see one amp channel and psu with meanwell switchers feeding the grlv (maybe i will put a transformer). bottom side of the pcb has exposed copper (large white spots) which will make contact with case to have more thermal mass. as you can see, there are lots of vias and they connect top and bottom part of pcb around output transistors to increase thermal surface. size of one channel section is 42x87 mm, and psu section is 98x61 mm. so i plan to fit finished project in 150x150mm case. i am a student so it will take time to build this thing, and of course a lot of hard earned money . i hope you like it! pictures: https://drive.google.com/drive/folders/1x2SQcV86kyMJL18twtRnseKntS9kgVBa?usp=sharing
    1 point
  24. Tintin´s Adventure with Frank Gardner (an exploration of Tintin's first adventure in Soviet Russia):
    1 point
  25. Great to hear about the new measurements which are in line with genuine 2SK216. When testing field effect transistors DY294 manual says “A short circuit should be formed between G and S pin. Otherwise the transistor can easily be damaged.” To make testing of k216/j79 a bit easier I’ve made a simple adapter for the DY294 tester.
    1 point
  26. Thanks James I was checking them with a wrong connection. Now I can read from 230 to 235v PD. I'm sorry it's hard to hold all of this with one hand
    1 point
  27. As a person I've always liked Jude. I know I'm in the house that "disagreeing with Jude" built, but as far as headphone villains go he's pretty low on my list. That said, this interview is a little weak in the way of journalism.
    1 point
  28. Thanks, James. Always impressive to see shipping cost more than the actual item: https://www.ebay.de/itm/283700277843
    0 points
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