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  1. Yesterday
  2. MASantos
    I measured the bias across all the 20R resistors and they're all flowing between 270-340 after a few hours with the top plate on. there are some variations in each channel between the 20R resistors, some might go to 340 and the one next to it only to 310. could this be transistor variation? I had the DC offset dialed to about +-5mV before installing the jumpers on the back side of the board. I'll remove the jumpers tomorrow and reset the trimpots.
  3. mikeymad
  4. simmconn
    I'm not sure if I understand your reply. In the Megatron the first stage uses 12AU7, and the second stage uses 12AX7. What do you mean by "provide 24db gain to drive pair 12au7s"?
  5. Dusty Chalk
    So beautiful ... my entry point was Citizen of Glass, so I like her older stuff and her newer stuff in the same way that I like older Tom Waits and newer Tom Waits.
  6. Dusty Chalk
    Fucking hell! #fuckcovid19
  7. skullguise
    Holy.....fucking.....shit......😪
  8. Pars
    340mV is rather high for a mini (17mA). What does your DC offset look like without the servo opamps in? I would check the bias across every 20R resistor for starters. Reset all trimpots to midpoint (with an ohmeter) and go from there. The 2 pots by the 255R bias resistors can cause some wonkiness if you go too far in the adjustment of them (same with the full size amps).
  9. Voltron
    COVID-19 is going to wipe out the old guard of jazz. Add Bucky Pizzareli, Wallace Roney, Manu Dibango, Marcelo Peralta, and Mike Longo. Sad times. 😢
  10. jose

    Speaker Porn

    jose replied to Hopstretch's topic in Speakers

    klipsch La Scala Awesome system with two Western Electric 16A Horn
  11. Oneguy
    I’m trying to finish re-flow oven in my spare time when normal people are sleeping, lol. It’s missing insulation, servo arm and that’s about it. A little touch up to the truck bed liner paint as well.
  12. MASantos
    So I finally got to finish my dynalo mini build. It is playing nice with 2SK170/2SK79 input jfets, 420ohm led resistors and 255 bias resistors. Temperature with cover on is 103C on left side (- channels) and 81C on right side (+ channels) transistors, is this sort of difference normal? I checked bias and L- is around 340mV while R+ is around 290mV. could this have anything to do with the offset trimpots? All the bias resistors 255ohm and led resistors (420ohm) measure within spec. Voltage drop on the leds around 1.65V When I remove the lid the temperatures drop quite a bit to around 60C-75C which is understandable. Sounds great though with my sennheiser HD650 recabled with 4 pin XLR. I would just like to understand this diferrence between plus and minus channels
  13. Dusty Chalk
    Whoa, You can now purchase on Amazon Prime on iOS. I am so fucked. The only reason I saved money up until now is that I’m too lazy to buy on one platform and watch on another. Thinking about Killing Eve. Any other recommendations? Unrelated: started Happy season 2.
  14. Knuckledragger
    Cat sneeze.
  15. Knuckledragger
  16. ironbut
    RIP Ellis! A sad day for NOLA! RIP Krzysztof Penderecki. A composer who was ahead of the curve. https://www.nytimes.com/2020/03/29/arts/music/krzysztof-penderecki-dead.html
  17. EdipisReks1
    My days, in social isolation, are spent listening to podcasts while I go about exercise, cooking, and fussing with cats. I haven't put on a non-Apple watch in weeks. I miss my real ones, but it's so nice being able to control a Podcast from my wrist.
  18. mikeymad
    Seems about right...
  19. MASantos
    Hello guys, after a long time, and with a lot of time in my hands due to quarantine I finally finished my Dynalo MK2 mini and reterminated my hd650 with a 4 pin balanced plug. Transistors are a bit hotter than I wanted, at 90-100 degrees with the top panel on. I need to go read about reducing bias. Sounds good though! Source at the moment is a bluesound node, need to go and find a better DAC with balanced out that doesn't break the bank.
  20. G600
    It's just insane to see how many iterations of alternative batteries you and Kerry produced!
  21. JoaMat
    Some progress. Replaces the original battery in my DIY T2, which was supposed not to be modified in any way… Schematic:
  22. Dusty Chalk
    This ^^
  23. n_maher
    Looks sweet! Nice work.
  24. skullguise
    So sad indeed....and RIP to the countless "non-celebrities" dying of this virus.....
  25. hyperma
    Probably because it's an electrostatic amplifier, the first stage needs provide 24db gain to drive pair 12au7s ,otherwise unable to reach amplititude.
  26. JoaMat
    Try those modern components and reduce high voltages to +/-400V (I’ve tried all except KSC1008 and J112). Old Modern 2SA1468 KSA1156 2SK216 KSC2690A 2SJ79 KSA1220A 2SC3381 KSC1008 2SK246 J112 2SK3675 FJPF2145 Mouser wants $51,51.
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