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About UFN

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  1. Agree with that. What makes you think that all these component replacements are in fact improvements?
  2. Not needed here because the offset is trimmable here - it wasn't on the original Dynalo.
  3. Two comments to the BoM: - Your LEDs are listed with a 2.1V drop. As Pars mentioned higher up in the thread you should normally use 1.7V for Kevin's designs (LTL-307ELC) - Can't remember the spacing for the 5pF capacitors, but I believe I used a high-voltage ceramic (75-561R10TCCV50) for this (also for the dynalo, although my boards are a different version).
  4. UFN


    Isolated semis you normally just mount with a bit of thermal compound between the package and the heatsink and a metal screw. That's the benefit of the full-isolated package - faster mounting (the downside is poorer thermal performance compared to a regular TO-220).
  5. I have boards but I haven't put them together yet. Can you just switch between ZF and SS, aren't the component values and placements different so that you have to choose a configuration up front?
  6. The plaque on the back should say "No actual knowledge involved in building this device" or something like that....
  7. IME yes the 2SC4686s have very low hFE. The last batch I bought all measured 22 and to be honest I thought the tester was broken until I checked the data sheet and saw that this is actually with specs (albeit at the low end).
  8. Yes, that's perfect. The 4M7 resistor on the bias out means that your meter will load down the bias voltage if you measure there. The test point is added before the resistor so you can measure the actual voltage accurately.
  9. Looks good. I don't really need more headphone amps, but do you have any spare boards? 😂
  10. A toroid transformer that's audibly humming is normally either badly made, overloaded or miswired. Does it hum without load as well? Also, you do know about shorted turns on toroids, right? https://www.bicronusa.com/resources/tech-guide-toroidal-power-transformers
  11. The pot model is called an Alps RK16812.
  12. UFN


    I have a YM 16622 which I bought app. 10 years and it's probably the most versatile watch that I have owned. The grey/neutral/understated look pretty much suits whatever else you are wearing and it means you can just put it on and forget about it. I've also worn it for a whole summer on a Nato-strap (grey/navy) and that worked really well also IMHO - and the funny thing was that very few people recognised it as a Rolex that way (but the few that did normally struck up some interesting watch-geek conversation afterwards ).
  13. Seeed should do the same as well (or thereabouts)
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