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About JoaMat

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  • Birthday 12/26/1955

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  1. Early stage work on a Circlotron (Aug. 2015). The prototype exploded during initial take-off roll.
  2. The ultimate DIY? A Stax SRM-T2!

    This is how the small board with trimmer and resistor looks like. I do think the T2 amp board by Kevin is a very good one. Easy to build, just put the right component in right position, solder properly and then you are done. If something goes wrong it’s possible to work on the board. And it's also a terrific board for experiments, tests, modifications…...
  3. What Are You Building Today

    Nice, manual control seems to work well.
  4. The ultimate DIY? A Stax SRM-T2!

    No, schematically like this: added RV3 and R60. I got it balanced when current was 5.1 respective 5.8 mA. When upper and lower tubes changed place I had to reset back to original setting – the unbalanced like of disappeared.
  5. The ultimate DIY? A Stax SRM-T2!

    Finally I did notice…… Four Bugle Boys. Ref. link Nice!
  6. The ultimate DIY? A Stax SRM-T2!

    No, trimmer is replaced by a resistor long time ago. The 10m90s current source is connected to ground and set to 1mA. Today I modified the input tubes current sources with a trimmer like T8000. Also changed the servo, using single OP tied direct from output via resistor to one of the lower tube cathode. One channel had more than 200 volts unbalance with no servo and both batteries set to 740 V. With the trimmer I managed to get outputs balanced – have been within +/- a couple of volts for half an hour now (servo disabled)….. to be continued….
  7. stax t8000 clone (well sorta)

    Moving the servo to the cathode would that be a good idea?
  8. stax t8000 clone (well sorta)

    How to make the servo less complex?
  9. The ultimate DIY? A Stax SRM-T2!

    The Drum Major leads the seven LEDs.
  10. The ultimate DIY? A Stax SRM-T2!

    Managed to squeeze in the eight diodes under the lf353 op-amp. Batteries resistors killing some 730 volt in series with the LEDs, or in my case lt1021, replaced with 10m90s. Works great in layout software. In real life -
  11. KGSSHV Carbon Build Thread

    Here is Delay circuit.PDF schematic. R1/C1 determines the delay time and R2/C2 flashing frequency. 12 V is fine, I use this circuit in two T2 power supplies with 12 volts. For time calculations google "R/C time calculation". Values in schematic gives me approximately a 50 seconds delay.
  12. KGSSHV Carbon Build Thread

    A delay circuit. Similar to Stax. LED flashes during preheat and then steady. Should work with CPC1117N. Will probably cost you more than four bucks.
  13. stax t8000 clone (well sorta)

    If dual tube input. One tube as upper device and the other as lower like T2 or one tube each side?
  14. stax t8000 clone (well sorta)

    How about a “dual section” tube input similar to the T2?
  15. stax t8000 clone (well sorta)

    How about increasing the 6DJ8 plate voltage? Might need additional ksa1156, what else?