In Reply to: RE: I am wondering whether the Neotech might be even better... posted by Chuck on February 22, 2008 at 11:44:19
I like oofer's review, but I suggest that you email Chris VH and ask for his opinion(s) regarding your amplifiers needs. I must wonder if the rhodium Furutech AC connectors were a prime factor involved in the Flavor 4 vs. Neotech NEP-3001 evaluation. Rhodium connectors are well regarded when placed on tube gear, but when placed on solid state gear, rhodium connectors may not be such a good thing (as I have found, except in special cases). It would be of interest to compare a Flavor 4 terminated with Oyaide 004's, gold Oyaide 079's and/or other warmer sounding AC connectors when placed on a solid state amplifier vs. the Neotech NEP-3001 (again, ask Chris). An important thing to consider is the Flavor 4's cross connected design is self-shielding, so the cable does not require a foil and/or a braided shield -- shielding is found by a number of folks to present a less open soundstage and a notable loss of dynamics, especially when placed on power amplifiers in particular...
I was always under the uneducated impression that twisting conductors was to reject EMI and cable shielding was against RFI?
Am I totally off base here but is one approach better for a particular type of interference?
And that for switching amps that radiate a lot of RFI, that shielded cables (with shield connected only at IEC end) are used more to stop RFI radiating out to other components, rather than keeping external RFI away from the switching amps? Any truth?
I tend to shy away from technical explanations since Iím not an EE and as a layman audiophile certain important things can escape my thoughts and/or wording... but, here it goes:
Twisted conductors offer a level of rejection of incoming noise and a level of suppression of outgoing noise, both EMI/RFI and digital noise. In the case of switching amps, the need to suppress outgoing RFI is a similar matter as the need to suppress outgoing digital noise from a digital components power cord which can radiate outward (radiant noise) from the power cord and thus pollute adjacent cables and components as well as directly pollute the AC power line (line born noise). A power line conditioner can then filter the line born noise that rides on the power cord conductors before it can pollute the rest of the system directly via the AC line.
Generally speaking, a foil shield is effective over a wide range of frequencies but is often intended to primarily address high frequency noise (such as RFI and digital noise) since it has low conductivity while a braided shield is often intended to address low frequency noise (such as EMI) since it offers high conductivity. So, the pros and cons are foil shields offer full coverage while a braided shield offers higher conductivity (but not 100% coverage). In many cases, a twisted pair is often sufficiant and does not need shielding since twisting creates a noise cancellation effect; in that noise that rides on one conductor and on it's opposite polarity cancel each other out. A twisted quad takes this noise canceling effect even further, as the geometry of a cross-connected star quad cable concentrates the electromagnetic field within the center of the four conductors and offers greater noise cancellation than that of a twisted pair. It is important that the twist rate (twists-per-inch) of a twisted pair is quite high since the steep angle (twist pitch) created by a high twist rate is vital for highly effective noise canceling. So, unless operated within an extreme RFI and/or EMI environment, most electrical noise entering into and/or radiating from a cable can be eliminated via a twisted pair or a twisted quads noise canceling effect without resorting to shielding which can present sonic drawbacks. Many audiophiles find that a noise suppression application rather than a noise rejection application is the key factor to consider when choosing between a shielded or an unshielded power cord -- the use of shielded power cords when placed on digital gear in particular (to suppress digital noise pollution) and switching amplifiers (to suppress RFI pollution) provide benefit towards an audio systems lowered noise floor (which is a very good thing).
One may find that an unshielded twisted pair interconnect when used for a phono level application will simply not reject EMI well enough to avoid audible hum -- a phono level interconnect cable will most often need to be shielded in order to present a quiet phono level signal (a twisted quad with a braided shield can be a very effective solution if higher capacitance than usual is not an issue). That same unshielded twisted pair interconnect will likely sound fine when used for line level applications -- in fact, a phono level interconnect is the only cable I can think of thatís *very* sensitive to EMI -- a phono level interconnect cable really needs a shield in order to reject gross audible hum.
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