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palchiu

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Posts posted by palchiu

  11. Megatron Electrostatic Headphone Amplifier

    in Do It Yourself

    Posted

    On 2016/5/5 at 9:47 AM, DonAudio said:

    I purchased a megatron board and power supply board from Joachim. I believe I have a complete list of the parts necessary to build except for the following. I was wondering if anyone would be able to guide me to an appropriate source for these items. Any help would be appreciated:

           Qty Value Ea     Schematic X-Ref
    12   2sc4686a 1.4 16.8   Q1-4, Q9-10
    4   2sa1968 0.7 2.8   either this
    4   ixtp01n100d 1.29 5.16   or this
    4   2sa1486 1.86 7.44    Q15-16
    4   2sc2705 0.46 1.84   Q11-12
    4   2sc2240 0.38 1.52   Q13-14
    4   2sa970 0.38 1.52   Q17-18
    2   LSK389 10 20   Q19,Q22
    2   2SC1815 0.19 0.38   Q20
    2   OP27GPZ 1.93 3.86   U2, 6
    2   2sc3675 1.22 2.44   Q5, 15

    This should be KGSSHV's BOM

  14. grounded grid

    in Do It Yourself

    Posted

    On 2016/1/3 at 4:30 AM, kevin gilmore said:

    About 300 ohms is the right number, don't know if that's total or just the tail resistor. Less ohms in the pot and most in the resistor is what we are aiming for.

    zener needs to change to 18v

    Dear KG,

    I'm working Ground Grid's BOM,  Zener should be 18V or stay 12V that label on board?

    Thank you!

     

    QQ图片20160725132035.png

  18. The Multi Amp aka Dynalo Mk2

    in Do It Yourself

    Posted

    3 minutes ago, Kerry said:

    I've been meaning to get to this for the last year or so.  I was motivated to see if I could get this down in size :)

    The current board is 4.8" x 6.8" and is an all in one.  Everything from power inlet to outputs. 

    I still have a few things I'd like to get to, including having an option for the regulators to be off-board as well.  I'm using some Mean Well switchers at 24V for the +/- rails then using the TPS7A4700 / TPS7A33 for a second stage regulation down to +/- 20V.  These regulators have 4uV / 16uV noise respectively (not bad).

    There's a switch in front that allows you to change between SE and Balanced inputs via some relays.

    Here are some pics of where it stands so far...

     

    It's awesome!!!

     

  23. goldenreference low voltage power supply

    in Do It Yourself

    Posted · Edited by palchiu

    Is possible add smd type soldering pad at GR LV's backside? smd tantalum capacitor looks are cheaper and easy to source.

    maybe just my stupid idea. :(

    On 2016/1/30 at 2:25 AM, Pars said:

    I had mentioned using Schottky rectifiers for this. I think I am going to have a few of these made:

    archive_top_small.png

    These are setup to take either a D201 axial diode (31DQ10 or equivalent), or also accept a TO220 package like an MUR820. I know the TO220s should probably be oriented 90 degrees from how I have them for airflow, but my intent was the axial Schottky diodes on these.

    I home-etched a pair of these and used them in my original Dynalo (headamp board). I used some Mill-Max right angle pins on those (3301-2-14-21-00-00-08-0), and plugged them right into the RS402 bridge holes on the PCB. If anyone with appropriate facilities wanted to compare these noise-wise to the packaged rectifiers, I could send them a pair to test.


    3301-2-14-21-00-00-08-0.JPG

    EDIT: Added John Swenson snubber across AC primary

    Love this board!

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