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hyperma

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  1. measured by a high voltage probe of oscillator, yes ,you right, the bias has fallen down when the probe touch the bias connector. I drawn this pcb by AD11 and made in JiaLiChuang, which has two factories in south of China, cheap and quick.
  2. Hello everyone, hope everything doing very well today. Few days ago I found two transformers in my dungeon, which named by my wife. I mentioned it has 16V out and double 110V in, so I guess perhaps could make something like stax srd-7. Then I made a pcb and give most places to voltage doubling rectifier, as same as srd-7, and... it works. Well somehow the bias unable to reach 580V, only around 490V, the sound quality, of course, bass section bit weak, so I have to turn the EQ on, then everything fantastic. BOM: 2 30W transformers 110-0-110 in
  3. Great great appreciate for your help. DN2540 is gone,reverse leakage been found,stable now.
  4. Assembling another kgsshv carbon, this time the positive 400V keep droping from first second, don't know why. Any diode or mosfet leaking? Don't know how to simulate. The tantalum cap or pair ksc5026s area about 95c, or 203F, hmmmmm....
  5. Sorry,the first stage 12au7s to drive 12ax7.
  6. Probably because it's an electrostatic amplifier, the first stage needs provide 24db gain to drive pair 12au7s ,otherwise unable to reach amplititude.
  7. Not making anything yet, but planning. After the Carbon I guess Megatron will be the next,so... A Megatron on more Old school style...not finished yet
  8. It's true, for diyer, Mouser, RS , Element14 or TME etc are best choice. Few month ago,I have bought some FAKE PCM1704s, of course they didn't work. The best way to find out who they are , is disassembling.....by fire, on microscope , I saw HC574 and TI mark on the die.......What a joke. Another example was my personal favorite op LM4562, I got some on same way, and matched their dies with AD744, remarked for sure. Also funny is in China AD744 is more expensive than LM4562 now. Hell......but seems Kevin already known everything about fake parts.?
  9. The price ..... worth that risk, AK4497 $35per/100pcs and $5 a package of TIP122(500 pcs).
  10. To be honest, I don't have much EXP on this, but 40 USD is enough to afford the alumium amplifier case with heatsink......few weeks ago I took a relay pcb from garbage bin,it's working on Carbon(or more carbon) now, don't you want to make your own one?
  11. Finally, well, I have fixed the "KG Carbon - more carbon" ......,in beginning I wanna make a "more carbon and lots cheaper version",but see what I got: DN2540 and IXCP10m90s I have bought from taobao.com......are fake, now show you guys photo: Fake DN2540(yes, I have bought all of them for testing): simply them didn't work ,that's all , I can read 455V from multimeter though probe touch the headsink,but....nothing happened, until I replaced the replica silicon: Mouser version: Taobao - Save your broken heart also bit expensive version:
  12. Really hate lead-free......unfortunately that's all I got, can't wait to show another PCB I have done with 63/37.
  13. the rms volt of transformer is 348v , I cant reach the cap due to parallel installed pcb ,measured 450v from 10m90s and c2ms drain by multimeter. On monday I will bring oscilloscope to studio.
  14. I will replace all bridge diodes by stth512s on Monday, just noticed something. I bought smt k389 from taobao , they are made by linear.sys , cost 45rmb or 5 pounds , mint choice.
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