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Etamin
Joined: Jan 05, 2011 Posts: 26 Location: NJ, USA
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Posted: Sun Aug 26, 2012 11:41 am Post subject:
WaveFreaker Wiring Question |
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This board has been sitting taunting me for too long now.
Ray's documentation recommends using coax cable to connect Input Jack to Input Level pot, and then to the board (Also X3 to board)
Should I connect the shield to ground?
If so, at both ends or just one?
Thanks, and apologies if this is a stupid question. I know enough not to hold the pointy end of the soldering iron, but my electronics knowledge is not very deep
Peter |
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JingleJoe
Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
Audio files: 14
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Posted: Tue Aug 28, 2012 5:20 am Post subject:
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I would connect both ends to ground, although I don't know for certain if that's what Mr Wilson would advise, but that would be the standard thing to do when connecting equipment together with coax leads. _________________ As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"
Green Dungeon Alchemist Laboratories |
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Etamin
Joined: Jan 05, 2011 Posts: 26 Location: NJ, USA
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Posted: Tue Aug 28, 2012 2:03 pm Post subject:
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Hi Jingle
Thanks. I don't know if Ray advises that, as I could not find it in his documentation. I was trying to avoid emailing him directly, partly to reduce his load, and partly, because the answer will probably benefit others here.
I will take your advice and connect the shield at both ends. I thought about it as I read your reply, and if I am not happy with the results, I can always disconnect one end, and/or the other. I assume Ray's recommendation to use coax is to reduce noise, so I will report back when I have tested.
Nobody should hold their breath on an update though, this is in my backlog, and may still be months from completion. I tend to get bogged down at the front panel layout stage.
Thanks, Peter |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Aug 28, 2012 2:05 pm Post subject:
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Wouldn't connecting both ends create a ground loop? |
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Etamin
Joined: Jan 05, 2011 Posts: 26 Location: NJ, USA
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Posted: Tue Aug 28, 2012 6:20 pm Post subject:
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I understand ground loops in a Piper Cub, but not in electronics
My patch cables all have two cores, signal and ground, and I don't think I hear A/C hum, so I don't know why this would be different.
I am open to suggestions (read - I need help!)
Thanks, Peter |
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elmegil
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
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Posted: Tue Aug 28, 2012 6:37 pm Post subject:
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That's a good point
I'll have to leave it to someone better versed than myself to say for sure. |
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Mongo1
Joined: Aug 11, 2011 Posts: 411 Location: Raleigh NC
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Posted: Wed Aug 29, 2012 8:24 pm Post subject:
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Typically it's best to connect 1 end of the shield. Frankly though with the length of cable we're talking about, I'm not even sure shielded cable is needed at all.
Gary |
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Etamin
Joined: Jan 05, 2011 Posts: 26 Location: NJ, USA
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Posted: Thu Aug 30, 2012 8:21 am Post subject:
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Hi Gary
Thanks. Well Ray recommends use of coax, explicitly in his doc, and I don't think I have ever seen him mention it elsewhere.
So, since I have some here, I will use that, and maybe follow your suggestion and only connect one end of the shield. Having the shielded cable shouldn't be detrimental, and I can always connect the second end of the shield or disconnect the first - that is easier than replacing the whole cable if I start with plain hookup.
I assume there must be something about this part of the circuit which is particularly susceptible to induced noise or something.
For general module wiring, I just use stranded Cat-5E cable with the sheath removed, and I haven't experienced any problems - well, none that my untrained ears can detect. I just have a lot of it, and the multiple colours help when making the connections.
Thanks, Peter |
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JingleJoe
Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
Audio files: 14
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Posted: Thu Aug 30, 2012 9:34 am Post subject:
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elmegil wrote: | Wouldn't connecting both ends create a ground loop? |
if i understand correctly, thats not how ground loops work. can we get a diagram of the connection being made? _________________ As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"
Green Dungeon Alchemist Laboratories |
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Etamin
Joined: Jan 05, 2011 Posts: 26 Location: NJ, USA
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Posted: Thu Aug 30, 2012 10:15 am Post subject:
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Hi Joe
This is a link to the project page http://www.musicfromouterspace.com/forums.html?MAINTAB=SYNTHDIY&PROJARG=DELAYEDMODULATION/DELAYEDMODULATION.php&VPW=1024&VPH=547
This is a link to the first page of the schematic as a PDF, although it does not show the Input attenuating pot http://www.musicfromouterspace.com/analogsynth_new/WAVEFREAKER/pdf/wavefreakerschematic_schem.pdf
Ray is recommending coax between the input jack and the 100k audio input attenuator pot (sig in one side, ground the other side, sig out fro the wiper), and from the wiper to the board, where it enters at point X6 about 2/3 down on the left side of the schematic linked above.
I just opened the link to a picture at the top of the document, which is here http://www.musicfromouterspace.com/analogsynth_new/WAVEFREAKER/images/wave%20freaker%20during%20test%201.jpg
From that it definitely looks like it is NOT grounded where the coax connects to the board, but I cannot see clearly if it does so on the panel. He doesn't explicitly show a ground connection on the coax on the panel wiring diagram here http://www.musicfromouterspace.com/analogsynth_new/WAVEFREAKER/pdf/frontpanelwiring_assembly.pdf
and Ray is usually very thorough. However, with my limited knowledge, I do not understand how coax with the outer shield just 'floating' would help.
Sorry for the lengthy post, I think I should just experiment, as nothing is going to break if I do/do not connect the shield.
Thanks for your help and advice.
Peter |
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Mongo1
Joined: Aug 11, 2011 Posts: 411 Location: Raleigh NC
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Posted: Thu Aug 30, 2012 2:49 pm Post subject:
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Quote: | From that it definitely looks like it is NOT grounded where the coax connects to the board, but I cannot see clearly if it does so on the panel. He doesn't explicitly show a ground connection on the coax on the panel wiring diagram here http://www.musicfromouterspace.com/analogsynth_new/WAVEFREAKER/pdf/frontpanelwiring_assembly.pdf
and Ray is usually very thorough. However, with my limited knowledge, I do not understand how coax with the outer shield just 'floating' would help. |
Yeah - if you don't ground it at all, it's kind of pointless. I don't typically bother with Coax on my stuff, but if I do I take a small piece of stranded wire and solder it to the coax shield, and then heatshrink around that. That makes it easy to attach the shield to a ground lug on the panel.
Gary |
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Etamin
Joined: Jan 05, 2011 Posts: 26 Location: NJ, USA
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Posted: Thu Aug 30, 2012 3:26 pm Post subject:
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Hi Gary
Thanks again, your heat shrunk ground lead sounds helpful, that will make it easier to manage at the panel, and easier to test with/without the ground connection.
Thanks, Peter |
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