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In Reply to: Audibility of group delay posted by op48no1 on April 28, 2012 at 07:44:53:
Why not simply check the dielectric and mechanical properties of the various wire insulations?
If on a simple level we can accept that different caps sound different, can't we simply look at the three major factors that give a cap its "sound"
the "conductor", the dielectric and the physical construction. Since we can assume the conductor to be constant between one makers wire, that leaves the dielectric and construction as the next thing to look at.
A simple dielectric test can be done with a megohm meter and plotting the resistance of a bifilar pair over time at various voltages. Once the dielectric is fully charged, the voltage can be reduced and the discharge characteristics can be plotted.
To get accurate results you would probably need to do the test with 10 identical samples of one color and average the results and then repeat with 10 samples of another color to see if there is a difference in the behaviors.
Next are the physical properties and that might require getting a bit more clever since i don't think a durometer will help unless you can get a solid cube of the insulation material. Maybe stretch a known length of wire to a specific tension and check the frequency of a "string pluck"
In both of these cases the goal isn't to prove anything but to document a difference. If a difference is noted, then one can move forward.
Even if a noted difference is observed in either of these tests, it still doesn't explain anything other than maybe there is a sonic difference. People on both sides of this are just lazy and all to often they "hear" / "don't hear" a difference, and take the first thing they can grab as proof of their position and run with it.
enough ranting and a story.
Once upon a time there was a young lad named clippy who took much abuse for his gratuitous use of scrap plywood, hot glue, clip leads and moving equipment to build his creations. One day the abuse became so great he made the occasional solder connection and replaced the hot glue with drywall screws. Still the jeers continued. Clippy decided he was going to show them and built a preamp in an aluminum chassis. In order to mount the big 'lytic caps, he sifted through the stuff on hand and came up with some leftover faucet repair washers to isolate the screw termnial connectors from the chassis. Upon first fireup of this creation the fuse blew. A week of troubleshooting ensued and no solution was found and the project went on the shelf and clippy held his head low in shame.
About a year later, clippy came across a genrad 1644 and proceeded to test all kinds of things for their conductivity. It was a new toy and he found out important things like a rottweiler is more conductive than a strip of formica. He also noticed an interesting property that several materials became more conductive with applied voltage and that is when the bell went off. He thought of the plumbing washers and sprinted to his junk box. Out came a different sized washer from the same pack. His DVM showed no conductivity. The megger however was able to test at much much higher DC voltages and show much higher levels of resistance. As the voltage went up, the resistance dropped drastically and the thought that the insulators becoming conductive at high voltage may have been the issue.
The carcas was brought out of hibernation and the caps isolated by air and the fuse didn't blow. Next came the search for a new insulation material and in the same bin were some washers from a different manufacturer. The megger showed them to be great insulators even at 1000Vdc. A quick swap was made and the project was finally completed and a Loesch 5687 linestage was born. Words cannot explain how how this beautiful creation sounded. I can still hear clippy's words to this day. He uttered a simple concise "this sucks" and went back to his plywood ways.
As a footnote to this story, the insulators that were conductive were black and the nonconductive ones were blue. Also the Blue nonconductive sink washers were the premium "long life" units.
While the above story is true, names have been changed to protect the ignorant.
dave
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Follow Ups
- RE: Audibility of group delay - dave slagle 21:43:35 04/28/12 (10)
- Thanks for this Dave....one of the best (finally) posts on this - Minussss3db 23:54:21 05/01/12 (0)
- "Why not simply check the dielectric and mechanical properties of the various wire insulations?" - Chris O 08:56:42 04/29/12 (1)
- RE: "Why not simply check the dielectric and mechanical properties of the various wire insulations?" - FenderLover 09:18:03 04/29/12 (0)
- RE: Audibility of group delay - Eli Duttman 06:53:15 04/29/12 (0)
- RE: Audibility of group delay - Triode_Kingdom 22:45:29 04/28/12 (5)
- RE: Audibility of group delay - casouza 22:02:35 05/01/12 (1)
- RE: Audibility of group delay - gusser 10:03:50 05/02/12 (0)
- You left out the punch line... - Lew 17:56:23 04/30/12 (0)
- RE: Audibility of group delay - Eli Duttman 07:08:22 04/29/12 (1)
- RE: Audibility of group delay - Stuben 15:22:22 05/02/12 (0)
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