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About jamesmking

  • Rank
    Limited Edition Bronze Participant


  • Headphones
    stax sr007a
  • Headphone Amps
    DIY T2, DIY joamat mini t2, DIY single box blue hawaii se, DIY hi-amp alpha centauri
  • Sources
    garrard 401, loricraft psu+plinth, hadcock 242 se, ortofon cadenza bronze, leema agena, mf v90 dac + golden reference LV psu + synchronous rectifier
  • Other Audio Gear
    quad esl 2805, leema hydra, townshend allegri, dcs 905 adc, ps audio p3, van den hul first cables, cardas golden reference mains cables, cardas golden reference speaker cable

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  1. quick heads up KSA1220AYS transistors are now END OF LIFE https://www.mouser.co.uk/ProductDetail/ON-Semiconductor-Fairchild/KSA1220AYS/?qs=ljbEvF4DwOOJTVoo5AYsWQ%3D%3D 😞 mouser is currently out of stock radio spares has stock farnell is out digikey is out
  2. My guide to golden reference high voltage (grhv) variants Here is my attempt at documenting some of the different GRHV board variations. (this will be work in progress for sometime) feel free to private message me with any additions comments, corrections etc. please note the schematic for version 1.5 has been reverse engineered by me from the gerbers and may contain error(s). location of the gerbers: https://drive.google.com/drive/folders/0B_iJFfZStuVhSE5nOHBVdTByR1k golden reference filename naming guide fat - boards which are wider and hav
  3. 1. part of the headcase experience is trawling a massive number of posts in one thread e.g. the carbon to find out about the grhv. Having a dedicated thread is seen as cheating. 🙂 2. to build a grhv you need C2M1000170D which are out of stock just about everywhere with little hope of being back in stock anytime soon... this is one of the issues delaying my megatron build. I can't comment on any sound quality differences, but there very few options if you want a 680uF cap that is 550V and will fit in a 2u case, i.e. be about 65mm in height or less. 450V or better 500V would
  4. I get mine from https://www.ebay.co.uk/itm/Stax-socket-5-pin-Pro-Bias-WHITE-Teflon-custom-made/184601921523?hash=item2afb21c7f3:g:CHcAAOSw2ENf7Jyy
  5. great in the winter time to keep hands warm. not so sure about the utility in the summer and i hate lugging around the batteries.
  6. (I would like to try NOT using my headphones or my ears or any other part of my anatomy) stax amp using multiple parallel push pull ef86 valves.... called the maxi minitron stax amp using push pull 211 valves called the ouch stax amp using push pull 101D valves called the almost-inplausible joking aside, a T2 using golden reference HV supplies (capable of the required +-500V and -560V) and only modern components.
  7. if the case has no letter/other designator for the grading then it's almost certainly a fake, (or possibly a reject?). The only time cases for transistors don't have an indication of Beta/hfe/gain or whatever the manufacturer uses to bin and sort them is if the manufacturer does not bin and sort them... e.g. 10m90s, C2M1000170D etc etc.
  8. If you are a reviewer maybe its a problem. If your aim is to get enjoyment from listening to music and your enjoyment is improved by hi-end hifi equipment that you can afford to buy then no it's not a problem. There is far more to enjoying music via hifi than just frequency response... dynamics, detail, stereo imaging, pure emotional enjoyment, good bass.... Im almost 50 years old and I don't have any meaningful response above 15K and above about 13k im getting rolloff. Do I care... only as much as that like everything else reminds me I am mortal and slowly falling apart. I can still appreciat
  9. using mousers parametric search I can't find any vishay resistors !% 50ppm 1/2w 350v working. koa mf1/2 series are same ppm, working voltage and wattage and similar size. https://www.mouser.co.uk/KOA-Speer/Passive-Components/Resistors/Film-Resistors/Metal-Film-Resistors-Through-Hole/MF-Series/_/N-7gz41Z1yzvvqx?P=1yzbppyZ1z0zlrrZ1z0ynpy I use them interchangeably with the Xicon. Xicon is far cheaper if you don't mind buying 100. koa is an option if you want to buy just a few. Per resistor koa is more expensive than the xicon. vishay MBB02070C are close to the xicon 1%
  10. 1. I assume the poster was referring to a circuit diagram NOT the marking on the case of a transistor. 2. I could not be bothered to see if the transistor in question was a bjt, mosfet or whatever. I probably should have put a / between the hfe and the word gain to cover more options. 3. Almost all of kevins circuit diagrams do not specify the transistor gain variant.... 4. I just had a conversation today with someone about transistors and almost every transistor we mentioned we did not put the gain letters on the end because it did not matter for the purposes of the conversati
  11. lsk389 generic name when you don't need/want to talk about the hfe gain.
  12. mains line voltage varies by +-10% or more, transformer output varies with load 10Vac on 475Vac is not going to make much difference....
  13. Glad to help starcat. The Megatron build is in the early stages. Im taking this one slowly because I have been suffering from work related stress for a while now... and don't have the energy to work at my usual build rate. I have reverse engineered the gerbers, built my own circuit diagram and edited the gerber files to my build style. But have not ordered any pcbs yet. Worse im going to use golden reference HV supplies and the world seems to be out of stock of C2M1000170D pass transistors and I don't have any spares. 30 to 40 non fake 2sc3675 ..... wow.... I have a total of 6 in my
  14. I built a blue hawaii with golden reference HV supply and the simple voltage regulator based lv supply built into the golden reference hv board. Later I added a golden reference lv supply which improved the sound a bit. I also replaced the diode bridge on the LV with a synchronous rectifier for even lower noise. The blue hawaii is a very good amp. Far better than anything I had listened to previously and was a quite straightforward build I did not modify any of the gerber files. I did solder the leds, the resistors you need to measure the voltage across to set the constant anode current and t
  15. All the T2 amp boards are a single monolithic slab (except the version I modified). The non shrunk versions are more than 400mm deep and will not fit into most diy chassis like the disapante 400mm. Also they have solder pads for a very expensive and now not easily available volume pot. Original T2 uses almost completely obsolete transistors which are both very very expensive (if you can even find them) and almost all the sellers e.g. ebay etc are selling fake parts anyway. t2schem.PDF So if you have not got the transistors already from known good sources you are looking at proba
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