[sdiy] power cables

Pete Hartman pete.hartman at gmail.com
Fri Aug 16 06:57:58 CEST 2019


The thinner gauge wire actually has more resistance.  I one tried using cut
up midi cables for power feeds (they were nice and supple unlike other
cables I'd made) and it was a while before I realized the nose/stability
issues I was having were due to the cables.

On Thu, Aug 15, 2019 at 11:48 PM Youssef Menebhi <
youssef.menebhi.79 at gmail.com> wrote:

> Well, I tested one more time - this time with a ground lift on the power
> supply.
> That did it. Looks like you were right all along, Oren!
>
> On Fri, Aug 16, 2019 at 12:43 AM Youssef Menebhi
> <youssef.menebhi.79 at gmail.com> wrote:
> >
> > Thanks for the suggestions so far - I poked around a bit and it helped
> > to know what you would have considered.
> > Having taken a closer look, I noticed that the hum was definitely
> > originating with the power supply. I tightened up the screws on the
> > transformer, which improved things about 50%. Still, oddly, the
> > thinner gauge cable seems to produce less hum.  I'm pretty certain
> > it's not a ground loop issue, at this point - since I've tried
> > multiple modules, independently.
> >
> > On Thu, Aug 15, 2019 at 11:26 PM Oren Leavitt <obl64 at ix.netcom.com>
> wrote:
> > >
> > >
> > > On 8/15/19 9:45 PM, Youssef Menebhi wrote:
> > > > Hi everybody,
> > > >
> > > > I've been building my own circuits for a little while now and have
> > > > just switched to a new power supply/connector arrangement. I use
> > > > bipolar power, plus and minus 12v.  What I've noticed, though, is
> that
> > > > when I use headphone cable (shielded ground) to pass power, I get a
> > > > small hum at the output. When I use even thinner gauge cable, I don't
> > > > get hum. Unfortunately, it's hard to get a hold of the ultra-thin
> > > > gauge cable.  Am I out of luck? Does anyone have any idea why this
> > > > might be happening?
> > > > _______________________________________________
> > > > Synth-diy mailing list
> > > > Synth-diy at synth-diy.org
> > > > http://synth-diy.org/mailman/listinfo/synth-diy
> > > >
> > >
> > > Hi Youssef,
> > >
> > > Sounds like you may have a ground loop somewhere. It may be that the
> > > thinner cable has enough internal resistance to break the loop. If you
> > > can track down the source of the loop and fix it, you'll leave yourself
> > > free to use heavier gauge wire for the power connections.
> > >
> > > May two bits
> > >
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