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  1. darwin999

    Cattle Driver - circuit anomaly

    For now, let me post this excerpt from this article on 'Electrolytics for AC Coupling' [https://northcoastsynthesis.com/news/electrolytics-for-ac-coupling/] Here's a simplified equivalent circuit diagram (for a polar aluminum electrolytic capacitor).... It is based on a more detailed...
  2. darwin999

    Cattle Driver - circuit anomaly

    Actually, I may have goofed and gotten over my skis on this - let me do some refreshing on this tomorrow and report back. And people who know this better can pipe in and answer (and correct my goofs). But it is quite common to see electrolytics in use w/ close to ~0 Vdc across them, and yet...
  3. darwin999

    Fuzzdog not shipping to US?

    Note the US wants the tariffs, but doesn't want to do the work - so the shipper has to do the work and then send the $ to the US. How generous! So the shipper will also have to charge an additional fee for their own time as well. With millions of packages every day, the logistics takes time...
  4. darwin999

    Cattle Driver - circuit anomaly

    Right, if the don't have separate specs for max DC and max AC, look for text like this (from a Panasonic cap spec sheet): The sum of DC and ripple peak voltage shall not exceed the rated working voltage and then they provide a frequency correction for the ripple (ac) voltage: Edit: Ack...
  5. darwin999

    Cattle Driver - circuit anomaly

    Interesting! I don't think there's much DC voltage across C11 or C19 in this circuit, just AC. But you could always use a nonpolar electrolytic and thus be totally safe - seems the best choice. I think most polar electrolytics should be ok w/ AC if they're rated for higher voltages, the...
  6. darwin999

    Fuzzdog not shipping to US?

    It's not the companies that are stopping shipments to the US, it's the national mail services in the European countries that are stopping them! The reason why is that the US hasn't made clear all the rules about how to collect the tariffs, how and where to submit them, etc. The US is doing...
  7. darwin999

    What's the special nature of Russian 2D503B diodes?

    From @thomasbe86's I-V measurements, they do seem to be fairly special. I don't see many other diodes in his data that are similar to the 2D503b's with regard to their combination of Vf & curvature. And almost all that are similar are no longer made and tough to locate. It's the curvature...
  8. darwin999

    What's the special nature of Russian 2D503B diodes?

    Translated by Google Thanks go to @Robert
  9. darwin999

    What's the special nature of Russian 2D503B diodes?

    I had seen this data on Ebay (upper left plot), but it's at too high of a current to be relevant for most pedals.
  10. darwin999

    What's the special nature of Russian 2D503B diodes?

    @PedalBuilder - many thanks, this is EXCELLENT!
  11. darwin999

    What's the special nature of Russian 2D503B diodes?

    @Barry - thanks! So it's I-V characteristics are equivalent to a 1N914A/1N914B. OK, got it. (y)
  12. darwin999

    What's the special nature of Russian 2D503B diodes?

    Humor aside, though, does anyone have actual data on them? E.g., I'd really like to see forward I-V data.
  13. darwin999

    What's the special nature of Russian 2D503B diodes?

    I see @Robert is selling Russian 2D503B Si pulse diodes, but don't know anything about their characteristics and could not locate a datasheet for them. So does anyone have a datasheet? Can anyone tell me about their utility, and for what pedals and situations they are useful? Thanks in advance!
  14. darwin999

    British royalty help

    Agreed. And the same applies to the ground wire on the PCB (the one going to the stompswitch), plus some of the solder connections on the stompswitch itself. Some other thoughts: Definitely check J201 biases with a voltmeter, make sure those are properly connected and working ok. Have you...
  15. darwin999

    What's on the workbench?

    I believe DHL's Express Service *is* doing imports w/ tariffs, while standard DHL is presently pausing shipments into the US because of the orange guy's new tariffs on de minimus shipments.
  16. darwin999

    Tayda packing and shipping

    With only $6.45 for shipping, you definitely avoided tariffs - you just got in under the wire. With your total, tariffs would have been another ~$40 on top of the shipping. So you won the lottery on this one!
  17. darwin999

    Plague Spreader

    Looks great! With a name like 'Plague Spreader", it should have RFK Jr's initials on it... Sorry, couldn't resist.
  18. darwin999

    This Week on the Breadboard: MOSFET Driver Redux

    Duly updated as v0.8. Thanks to @Chuck D. Bones.
  19. darwin999

    Jlcpcb and tariffs

    Damn straight - check this out: Multiple postal services around Europe (and possibly elsewhere) say they are suspending the shipment of many packages to the United States amid a lack of clarity over new import duties. The US didn't even provide the rules regarding all the details of collecting...
  20. darwin999

    Jlcpcb and tariffs

    HOLY SHIT, this will impact just about everything - e.g., appliances, computers, TVs, absolutely anything electronic, kitchenware, cars, you name it! This is just nuts. The cost of calculating & justifying the tariff will be so significant that it will add even more $$$ on top of the tariff...
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