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UFN

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Posts posted by UFN

  4. grounded grid

    in Do It Yourself

    Posted

    Thanks @sorenb, looks like my math was correct. I built a PSU dummyload a while ago, so that's not a problem.

    If I have to start looking around for cheap EL34s for testing then so be it, but I was hoping I could maybe put my collection of Fluke meters to use instead :rolleyes:

  5. grounded grid

    in Do It Yourself

    Posted

    Been slowly plugging away at a pair of GG-boards for a while now and I'm getting ready to order the last parts (I hope...). Two questions though:

    Kevin quoted 16W dissipation for the 10m90s a few pages back, but is that per board or per device (i.e. 32W per board)? I'm planning to use a 450V PSU, probably a BH-PSU since I have a board left over and I'm not sure I can fit a Carbon PSU in the intended chassis anyway.

    Also, once the amp boards are done is there a way to verify that all voltages are OK before I plug in tubes? (or better still, before I even buy the tubes ;) )

     

    //UFN

  7. KG Balanced Dynahi build discussion thread

    in Do It Yourself

    Posted

    19 hours ago, Pars said:

    I'm just looking for the best inexpensive device tester for validating devices. DY294? The Atlas DCA (though it is 4x the price of the 294, and won't do higher voltages).

    Not sure about the DCA75, but FWIW I have both the smaller DCA55 and the DY294. The DCA55 is brilliant but the DY294 has a couple of features that the DCA55 hasn't. First of all it has the HV breakdown test for (potentially) spotting fake HV-transistiors and secondly it can measure BJTs at different base currents. The DCA55 only tests BJTs at 2.5mA collector current which honestly isn't much if it's a driver- or powertransistor.

    So, my conclusion would be that I actually need both :P If I had to only get one it would probably be the DCA55 though, and the DCA75 might have even more features.

     

    //UFN

  8. TKD 4CP-601 & 4CP-2500 4-gang volume pot and PCB GB

    in Do It Yourself

    Posted · Edited by UFN

     

    48 minutes ago, MLA said:

    Maximum tracking error in this config for all pots is around 2-3%. However, that 2-3 percent only shows up at the high output levels ( think last quarter of pot range towards full volume). Below that, tracking error is 1 % or less. 

    With the usual reservations for unknown errors in test setup and/or my math, my conclusion is that we got a fine lot of pots this time around. Should you find otherwise when you get your pots, we'll work it out with TKD.    

    Excellent! Much appreciate your efforts on this :D 

     

    //UFN

    • Like 1

  14. KG Balanced Dynahi build discussion thread

    in Do It Yourself

    Posted · Edited by UFN

    That's probably from the first GB (check the beginning of the thread). It should be fine to build if you have the parts, but they are all obsolete now, so if you are missing something it might be hard to get hold of. IIRC the newer boards were mostly made because the old parts weren't available any more, not because the newer parts are better.

    //UFN

    EDIT: Hang on, you are writing "the board" as in one? - remember one board = one channel.

  22. The Headcase Stax thread

    in Headphones

    Posted

    Agree that not quoting a price up front can be problematic. However, not wanting payment until the customer as completely satisfied with the work done sounds like a commendable business practice (it's tends to be the other way around - pay up front and then pray that you'll be happy with the work afterwards ^_^).

    //UFN

    • Like 1
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