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Post by ChrisK on Jun 14, 2008 14:09:15 GMT -5
Good job. I've kept quiet for a little while since all of this testing went a slightly different way than I would have done it. While the details of what I was preaching (and with my general lack of patience I tend to, too soon) were not completely seen, I didn't have to do the testing. I don't "see" the benefit to the double switching scheme, whose real difference is the uncoupling of the unselected pickups from their ground connection as well as their output connection. In essence, with a mediocre cable shield/ground connection to the amp, and the injection of sensed EMF into said connection causing the modulation of the guitar signal, the signal will contain excessive noise. Removing these ground side connections from unselected pickups will eliminate their contribution to this injection mechanism. However, there still is at least one pickup connected at all times which provides the termination of the cable at the guitar end by its output impedance. The noise would be a lot more noticeable without this (I didn't say worse for a reason) and with no pickups connected by either of their wires, less might be injected than if they were still connected to ground. Anyway, noise is noticed by its contribution to the signal to noise ratio (S/N). When one has signal, the noise seems less. When one doesn't.... Do we all remember that this is a Squier in all of its unshielded, cut-corner, entry-level, likely $50 to $70 (mean, labor, and burden) cost, ER glory? Folks typically spend about 0.5% to 1% of the cost of their home on yearly security. What do folk typically spend on cables for Squires? I tend to believe that, if something makes sense, it tends to already be in practice. Balance.
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Post by sumgai on Jun 14, 2008 14:29:57 GMT -5
Oh? By whom, may I ask? Two things stand out here. One is that (I think) it was ChrisK hisownself who reminded us of ground loops, way back when. urthman's situation, that of a very "dirty" environment that challenges a guitar's noise-reduction abilities, is probably also highly ground loop enabled. Think about it....... The ducting or piping is indeed about as grounded as one can get, but that's abolutely not the same ground as the one used by the building's wiring harness. By law (building/electrical codes), and by oft-proven scientific testing, the two grounds should be as far apart as practicable. That right there will introduce a ground loop of high resistance, and will almost assuredly introduce an order of magnitude more noise into the signal path. DD's testing shows not much difference, slight if any. But in an otherwise already dirty environment, such as an old nightclub with all of urthmans' decorations, the chances of a ground loop introducing even more noise are fearsomely higher. There's a very good chance that his schema worked, for just this reason. However, this is still not the route I'd take. As a minimalist, I'd still do the least harm to the signal path by virtue of introducing no unneeded switching. (Defined as redundant, therefore of no benefit.) If the noise continued to be a nuisance, my next step would be to isolate the ground(s) of all of my house-powered equipment - that would have the same effect, and be safer to boot. (But I still wouldn't give up my RF cable! ;D) HTH Oh, and the other thing......... DD, this thread is too long, and gets off the point too often, so will you please write an article around your experience, include the images of your results, and post it to the Reference section? We'll title it "How Much Benefit Do You Get From Shielding", and put paid to all those doubters out there. ;D Thanks buddy, we'll all owe you one for this! sumgai
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Post by ashcatlt on Jun 14, 2008 18:30:44 GMT -5
DD thanks for spending so much time on this. If nothing else you've got a new POS guitar and a bit better understanding of strat wiring. Unfortunately, I don't find your test to be exactly definitive for the reasons ChrisK outlined above. Too many uncontrolled variables. I'd be happier if you did it like a hundred more times and presented us some form of average or composite result. The effects of shielding are pretty well represented, though. I devised a somewhat different test. Not sure that it's much more scientific, but the results are interesting. I used my Ric rather than a Strat. Like most every guitar in the world, the signal return of both pickups are connected to ground in all switch positions. What I did was to plug a 1/8" male>male cable into the headphone out on my computer. The tip was connected via alligator clip to the point on the switch where the neck pickup hot is soldered. The sleeve was connected to the gound point of the output jack. A second cable was connected to the mic input on the computer. The tip of this was connected to the hot output lug of the out jack, with the sleeve connected to the same ground point. I cued up a short loop of one of my songs (for copyright reason) in Sonar and set a second track to record from the mic input in loop mode, creating a new track on each pass. The first pass had the song muted, switch in the neck position. Second pass was the song playing, neck position. Third pass was song playing, bridge position. I didn't bother to try it with the neck pickup's signal return disconnected for two reasons: 1) I didn't want to have to re-solder the thing 2) I think we can agree on what the result would have been So here's the picture of the top half of the waveform, rendered as one wave and normalized so the peaks hit 0 db. And if you want to know what that sounds like.
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Post by D2o on Jun 14, 2008 22:45:55 GMT -5
EDITED TO INCLUDE THE FOLLOWING:Thanks, Chris and sumgai, for your kind words and your endless assistance. I was a little short for time over the weekend and should have thanked you both much earlier. By the way, Chris, you wrote: That is how I felt about this too, but urthman kind of reminded me of an insurance colleague who once told me about a time when he was trying to convince a prospective client of a better way to build a mousetrap. The prospect insisted that if it was such a great idea, why wouldn't someone have not already told him about it? My colleague's response was " I'm telling you about it." My colleague shared his idea with me, and he was right. So, even though people have had 80 years to get pickups working as well as they are ever likely to, I guess we had to be open to the possibility that something can be improved ... well, open within reason, anyway. Since urthman's idea didn't adversely affect anything, I suppose one may be able to use it in conjunction with shielding. I did not and will not investigate whether the two are compatible, I will leave it to urthman to measure his guitar as it is now and then shield and measure it afterwards to see if it is any quieter than before. [/EDIT] Thanks, Ash - and an interesting idea you have come up with there! I agree that the more samples the better, but when I heard about the same amount of hum, and saw that the results indicated that there obviously wasn't any practical benefit to this, I saw no reason to get carried away. Don't forget that I was gunning for this idea to work ... I mean, how cool would that be? So I didn't take any shortcuts, but drawing this out did not seem warranted, that's all. Nevertheless, just to set you at ease, I can tell you that I did a little more than I have let on - it's just that it wasn't required to make the point (plus it would have been a real pain to set these large illustrations up to be clearly comparable). The illustration I presented before was just the bridge pickup in each situation. In reality, for each wiring option, I measured each switch position 1,2 3,4 & 5 from 3 feet from the computer with the monitor on, ditto with the monitor off, ditto from 12" from the amp - at a 45 degree offset from the speaker, and ditto from 6" from the amp speaker - directly in front of it. I performed a series of tests from various locations, for each switch position, like the one below (for the stock strat) - but for each wiring option. I hope that helps. EDITED TO INCLUDE THE FOLLOWING:P.S. I meant to tell you that I held a file parallel to ends of the frets and got rid of the sharp ends, and then sanded the filed area down so that it was reasonably "finger safe" to actually play the newly shielded guitar. It took away a little bit of the wood, er, "wood-like" material of unknown composition at the edge of the fretboard, but I confess that I played, and liked playing, that POS for the whole weekend ... a very different guitar than that POS I bought. Just to be safe ... WARNING / ATTENTION / ACHTUNG: DO NOT FILE AS I JUST DESCRIBED ON ANYTHING BUT THE CHEAPEST OF CHEAP GUITARS (examples of such finger shredding beauties are typically found on First Act, Robson, Ashbury, Nova, Hannah Montana, etc. you get the drift - basically, guitars that have such poor fit and finish that they are essentially unplayable without filing the ends of the frets).
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Post by reTrEaD on Mar 13, 2012 12:13:23 GMT -5
This thread is ancient. But it's hilarious. It might even be worthy of "required reading" for all new members. I came across it while playing "the birthday game". (clicking on the member profile links in the "Today's Birthdays" section of the front page. I had considered waiting until April 26 (karma to the first one to spot the significance) to post, but I'm not all that patient. ITT: ChrisK uses his wit, engineering expertise, and abundant sarcasm to correct a poser-wannabe. Awesomeness ensues. It's based a classic case of someone perverting valid concepts with half-truths and extrapolating to hyperbole, then creating a self-aggrandizing site where he is out to turn "common misconceptions" on their ear. Fortunately, discussions reveal the fallacy in the "logic" employed by hacks like this. What's most amusing in this case, is that the hack membered-up and joined the discussion! Most of the technical details have already been addressed, but I couldn't resist dissecting some of the "logic" employed to "defend" his use of the term "magic". He might have been more successful if he had invoked the fifth amendment. 1. The term 'Magic' in my little article is metaphoric - a common literary device used in much Western writing, but not that common in technical documents - it is generally easier to sell magical ideas than actual science -and- most misconceptions concerning science tend to be the result of magical or wishful thinking -- hence, the metaphor is appropriate. "it is generally easier to sell magical ideas than actual science -and- most misconceptions concerning science tend to be the result of magical or wishful thinking" Wait ... WHAT? It looks to me like this guy just admitted that his OWN misconceptions were the result of magical and/or wishful thinking. And he's selling them as "magic", rather than science, because it's an easy sell. Yeah, I'd say the metaphor is appropriate. Highly appropriate! Anyway, for those of us who weren't around to witness this in real-time, here's a chance to catch up on some GN2 history. And for those who were here, enjoy the trip down memory lane.
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Post by sumgai on Mar 13, 2012 14:33:26 GMT -5
reTrEaD, All I got out of this "trip down memory lane" was a reminder that I no longer can do this kind of thing any more! But be that as it may, in regards to your slight bashing of urthman's defense of "magic", I've got one word for you - Dianetics. Which morphed into another word; Scientology. IOW, it is easier to "sell" mumbo-jumbo than the real thing. Such is the sad state of affairs in most all things societal. sumgai
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Post by newey on Mar 13, 2012 18:33:10 GMT -5
I think PT Barnum made much the same point. Nevertheless, most of us don't respond this way in everyday life. For one example, when you become seriously ill, do you: A) Consult a Board-Certified specialist in Internal Medicine? B) See your local witch doctor? Oh, and don't give me the Karma point for spotting Chris Kikta's birthday. I had an unfair advantage . . .
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Post by reTrEaD on Mar 13, 2012 20:21:17 GMT -5
Oh, and don't give me the Karma point for spotting Chris Kikta's birthday. I had an unfair advantage . . . Hint: not a birthday.
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Post by JohnH on Mar 13, 2012 21:14:02 GMT -5
April 26, is ANZAC day, our main remembrance/memorial day that celebrates the heroism and sacrifice of Australian and New Zealand armed forces over the last century.
But also, I believe it was the founding day for GN2 in 2005 - I was there. I was also online, as was Wolf, a few days before when the old GN went down due to hacking. It wasnt me.......
I'll take that point now thankyou.
John
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Post by newey on Mar 13, 2012 21:17:07 GMT -5
(oops)
Registration date was what I meant, musta had birthdays on the brain (planning for my wife's 50th party in two weeks).
I believe the first posts on the Board were April 25, 2005 (The Rules, by RandomHero). So Chris registered here the next day.
This was all well before my time here.
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Post by JohnH on Mar 13, 2012 21:40:16 GMT -5
(oops) Registration date was what I meant, musta had birthdays on the brain (planning for my wife's 50th party in two weeks). I believe the first posts on the Board were April 25, 2005 (The Rules, by RandomHero). So Chris registered here the next day. This was all well before my time here. OK, I relinquish my one point claim, being a day off! J
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Post by reTrEaD on Mar 14, 2012 0:19:05 GMT -5
Close enough guys. It was the day ChrisK registered. (about 3 days after the board was created) And thanks for the cultural lesson, John. +1 for each of you.
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Post by KIIMH on Mar 14, 2012 12:19:52 GMT -5
tihs is a concidense, as paril 26 is PROZAC day for me.
kyle
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