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    I have some questions regarding grounding in my VTA hardware.

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    spin

    Posts : 11
    Join date : 2015-01-11
    Age : 35
    Location : Delaware

    I have some questions regarding grounding in my VTA hardware.

    Post by spin on Sat Feb 07, 2015 8:41 pm

    I'm nearing completion on several of my projects and had a question regarding grounding. In addition to the ground wire run to star ground, all of the boards are also grounded to the chassis through the stand-offs. In my previous experiences with building high gain guitar amplifiers this was something I went out of my way to avoid. Could someone give me a quick explanation why this is a non-issue?

    Thank you for your time.

    tomlang

    Posts : 34
    Join date : 2009-08-12

    Re: I have some questions regarding grounding in my VTA hardware.

    Post by tomlang on Sun Feb 08, 2015 11:15 am

    I suspect the board was designed to reflect the design intent of the original design.  I'm sure you noticed the original design is not star grounded at all.  The entire chassis is the circuit ground.  The output tube cathode resistors go directly to the chassis at each tube, etc.

    I insulate the vta board from the chassis as I run the chassis ground as the green wire from the 3 wire cord.  The circuit ground is connected indirectly to the chassis ground at one point via ground loop breaker.  Example:  http://www.pmillett.com/dcpp.htm

    spin

    Posts : 11
    Join date : 2015-01-11
    Age : 35
    Location : Delaware

    Re: I have some questions regarding grounding in my VTA hardware.

    Post by spin on Sun Feb 08, 2015 12:31 pm

    Thank you, that kinda reinforces my thoughts. I will procure the proper shoulder washers to isolate the boards from the chassis.

    tomlang

    Posts : 34
    Join date : 2009-08-12

    Re: I have some questions regarding grounding in my VTA hardware.

    Post by tomlang on Sun Feb 08, 2015 1:09 pm

    I found it easiest just to buy some nylon screws and nylon stand-offs. YMMV.

    spin

    Posts : 11
    Join date : 2015-01-11
    Age : 35
    Location : Delaware

    Re: I have some questions regarding grounding in my VTA hardware.

    Post by spin on Sun Feb 08, 2015 1:27 pm

    tomlang wrote:I found it easiest just to buy some nylon screws and nylon stand-offs.  YMMV.
    I would agree with you. But on this particular application (the MK3 driver board) the standoffs are really short. the screw goes through the chassis, through the standoff, then through the driver board with a nut on the end. I thought about using a nylon screw, but from a purely aesthetic standpoint, I would prefer to have the stainless screw head as it's visible. I typically use the 1/2 inch nylon standoffs with threaded brass inserts with my other projects.


    tomlang

    Posts : 34
    Join date : 2009-08-12

    Re: I have some questions regarding grounding in my VTA hardware.

    Post by tomlang on Sun Feb 08, 2015 1:37 pm

    Aesthetically, I have "nylon head syndrome". I haven't figured out what "prize" I will award if anyone notices...

    tubes4hifi
    Admin

    Posts : 1292
    Join date : 2008-11-30

    Re: I have some questions regarding grounding in my VTA hardware.

    Post by tubes4hifi on Sun Feb 08, 2015 1:59 pm

    from a purist point of view, you are correct the board mounting holes shouldn't be grounded, but from a practical point of view,
    I've never heard any of these amps with any noise at all. You can either cut the grounds on the PCB or use nylon mounting hardware.

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