MOTM

Actually mine is a partial star.  Two points anyway.  The top and bottom 
row are on separated ground wires.  The second TM I built I did as Larry 
and ran all the grounds out, keeping the CV and audio separate.  But I'm 
not sure which is better.  I can not hear, see, feel, or taste 
anything  different between the two.  But then I  don't know if I'm a 
qualified connoisseur of fine  circuitry :)

dave

At 08:44 AM 2/26/02 -0600, J. Larry Hendry wrote:
>OK, I'll offer up an opinion and disclaimer.
>
>I did not exactly follow John's recommendations.  But, I did use up all the
>ground pads available on the PCB.  You will notice I combined some grounds
>and not others.  I did not mix CVs and audio or anything else that logically
>made sense to me might interfere with one another (which seemed to be John's
>basic approach too from my casual observation).
>
>Here was my small brain's thought process. In an unbalanced scheme, there is
>as much signal current in the shield as the signal conductor.  So, if you
>have only one wire from jacks to PCB, then all these currents mix on the way
>to the PCB.  And, no matter how hard you try to keep them separate, you
>cannot completely because they jacks are all quite well bonded at the panel.
>So, some interaction between CVs and audio caused by the voltage drop in the
>ground connection will occur.  Ideally, there would be no common path
>(isolated grounds, isolated path on the PCB).  But, that of course is not
>the case.
>
>My thought was that I wanted as little interaction between I/Os as possible.
>So, that meant to keep the R of the ground connection from jacks to the PCB
>very low.  Therefore, I went with the multiple wire method.  I assume the
>single wire method might work just as well, provided the wire was not
>significantly undersized. Since there is a limit to the wire size that can
>connect to the TM PCB, the multiple wire path made sense to me.
>
>Disclaimer: I don't posses the educational accreditation to support my
>theory.  This is not meant to be an instruction on how it should be done,
>but rather an insight on what I was thinking when I largely just followed
>the designer's recommendation and made my own decisions.  I have never built
>any of my modules with the "strap 'em all together, one ground wire" method.
>In fact looking at my Multimix, I see I used shielded I/0 and used heat
>shrink near the PCB where I tapped the PCB end of the shield to run a ground
>wire over to the SCRN connection (unless using the adjacent ground
>connection).  I am also not offering any criticism to the other methods.
>
>Larry (now you know how my crazy brain works somewhat) Hendry
>
>P.S. Since the TM is basically a "lo-fi" device AND according to our quiet
>list friend Harry B, "BDDs suck" does it really matter?
>
>----- Original Message -----
>From: thomas white <djthomaswhite@...>
>To: <motm@yahoogroups.com>
>Sent: Tuesday, February 26, 2002 8:33 AM
>Subject: [motm] Conversions Question
>
>
>I am in the process of converting my Blacet Time Machine to MOTM format and
>pose this question. Since all of the grounds on the Blacet schematic
>individually "star" back to one point on the pcb, can't I simply connect all
>the jacks with unshielded wire in a star type web and run one connection off
>this web to the pcb ground for the same overall effect? I used the
>unshielded wire method and it appears to work fine. Although in looking on
>Larry Hendry's page I noticed that his model uses Blacets wiring scheme
>while Dave Hylander uses the "Oakley Type" unshielded wire approach as I
>did. Comments?
>
>Thomas White
>
>PS. Nice to not have to fiddle with 1/8 cables anymore :)
>
>
>
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