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<p>John,</p>
<p>I agree with you, but I think the Pin 1 of the input connector
should be connected directly to chassis, preferably using a
purpose designed XLR connector if you're going to be in very high
RF. I think Neutrik has an XLR connector with Pin 1 bonded to the
connector housing which is then bonded to the chassis. The power
supply should be grounded to the chassis via a short lead --
remember ohms-per-square? The chassis is a lower impedance than
any wire (as long as it's metal. <br>
</p>
<p>I agree with the twisted triplet from PS to amplifier board. I'm
not so certain the chassis connection needs to come from that
triplet, but rather a shorter jumper.</p>
<p>The output, while not shown, should be a floating jack with a
capacitor directly to ground for RF bypass with the common signal
lead coming from the amp module. If there are two amp modules (one
per channel), that requires additional wiring.</p>
<p>I defer to Bill Whitlock in this. I think I'm accurately
portraying his suggestions, but there is a lot of stuff on the
Jensen Transformers website (or at least there was before it was
bought by Radial Engineering).</p>
<p>Cheers,</p>
<p>Richard<br>
</p>
<div class="moz-cite-prefix">On 2023-12-02 1:08 p.m., John Chester
via ProAudio wrote:<br>
</div>
<blockquote type="cite"
cite="mid:476f6c96-d086-4ff4-b96e-b6fe75f3d81b@jkc-lab.com">On
12/2/23 12:21 PM, Bob Katz via ProAudio wrote:
<br>
<br>
<blockquote type="cite">Naturally, I started a firestorm on
facebook asking a question about grounding in a headphone
amplifier I'm building. </blockquote>
<br>
<br>
A ground loop running through both the headphone amp and the power
supply board doesn't seem like a good idea to me. Here's my
revision of your diagram:
<br>
<br>
<a class="moz-txt-link-freetext" href="https://photos.app.goo.gl/gWfABiqTc82mKZLV9">https://photos.app.goo.gl/gWfABiqTc82mKZLV9</a>
<br>
<br>
I wouldn't opine on whether the ground loop will upset the power
supply without seeing both the power supply schematic and the PC
board layout -- assuming it's not a potted blob. Best to just get
rid of the ground loop. Zero volts to chassis ground should be on
the DC side of the power supply, never on the AC side.
<br>
<br>
Zero volts to chassis should occur before the zero volt line gets
to the headphone amp, not after. IMO the most cautious approach
to power supply wiring would be to run 3 twisted wires from the
power supply to the chassis ground point, where the zero volt line
gets connected to chassis, and then continue with 3 twisted wires
to the headphone amp board.
<br>
<br>
-- John Chester
<br>
<br>
<br>
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</blockquote>
<pre class="moz-signature" cols="72">--
Richard L. Hess AES Life Fellow
Aurora, Ontario, Canada <a class="moz-txt-link-abbreviated" href="mailto:richard@richardhess.com">richard@richardhess.com</a>
<a class="moz-txt-link-freetext" href="http://www.richardhess.com/tape">http://www.richardhess.com/tape</a> 647 479 2800
<a class="moz-txt-link-freetext" href="http://www.richardhess.com/notes">http://www.richardhess.com/notes</a> Quality tape transfers</pre>
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