Wall Outlet Oyaide, Furutek, Wattgate, and others

Regarding the comments about resistance and voltage drop, as I see it a couple of things should be kept in mind:

1)In the "New Heavyweight Contender" link which Dave provided, the highest resistance shown for any of the receptacles listed is 2.7 milliohms. That is 0.0027 ohms. Even for a large current spike of say 20 amps, that would result in a voltage drop of only 20 x 0.0027 = 0.054 volts (about one-twentieth of a volt). For components other than power amplifiers which draw large amounts of current, the resulting voltage drop would be way less than that.

Given typical gauges and lengths of the house wiring, turning on a 60 watt light bulb that is on the same circuit as the audio system, or leaving a low powered line-level audio component in the system turned on while it is not being used, will result in the AC voltage decreasing by about as much or more than 0.054 volts.

Furthermore, for audio components having regulated power supplies (although that excludes most power amplifiers), that very tiny voltage reduction will be reduced much more by the voltage regulator circuitry in the component.

2)Presumably there is a specific line voltage at which a particular component will sound its best, say 120.0 volts for example. If the AC voltage at the particular location happens to be higher than whatever that number happens to be for a specific component (and it is extremely common these days for AC voltages to be significantly higher than 120 volts), minimizing resistance and consequently voltage drop in the receptacle, the power plug, the power cord, etc., may actually degrade the sound, if it makes any difference at all.

Regards,
-- Al

Keith (Audiolabyrinth), take a look at this reference, particularly Table 1 on page 2. You'll see that the standard for 120 volt service (at the entrance to the house) is 120 volts +/- 5%, corresponding to a range of 114 volts to 126 volts.

Regards,
-- Al

Hi Dave,

To answer your questions clearly, I should probably first state that “60 Hz AC power" consists of a vast number of different frequency components. The highest amplitude/biggest of them is the 60 Hz component, of course. But there are also components at much higher frequencies corresponding to the brief high current spikes you mentioned earlier, probably extending up to tens of kHz, particularly in the case of power amplifiers. And there are frequency components at integral multiples of 60 Hz (i.e., 120 Hz, 180 Hz, 240 Hz, etc.) corresponding to harmonic distortion that will be present in the waveform to some degree. And there are essentially an infinite number of low level frequency components corresponding to noise, extending up into the RF region.

In answer to your questions, yes, strictly speaking a “resistance” at any frequency other than zero Hz (i.e., DC) should be referred to as “impedance,” which reflects a combination of resistance, inductance, and capacitance. And, yes, resistance in series will add to impedance.

In a local (in-house) power distribution system, however, impedance at 60 Hz will be dominated by resistance. Inductance and capacitance will become more significant at the frequencies of the much higher frequency components of the AC waveform. But I would not expect the inductance and capacitance of an outlet to have a great deal of significance in relation to the inductance and capacitance of the power cords and the house wiring. Everything else being equal, the inductance, capacitance, and resistance of conductors are proportional to length (although of course everything else is rarely precisely equal).

In answer to your last question, the impedance of the power delivery system should be low, at least at frequencies up to and somewhat beyond the frequency components corresponding to the brief high current spikes that have been mentioned. (Series impedance that is high at frequencies greater than that may be helpful in reducing noise, but I would not expect an outlet to play much of a role in that regard).

**HOWEVER**, for any design parameter that should be low there exists a point beyond which further minimization will:

1)Be overkill, that increases cost but accomplishes nothing, and/or

2)Be negligible in relation to the contributions of other things in the path that also contribute to the parameter, and/or

3)Be accomplished at the expense of other parameters that may be significant.

The basic point to my previous post was to provide a quantitative perspective on the differences in resistance that were cited in the reference you provided. Consistent with my comments above and in that post, I believe that if in fact there are differences in the behavior of those outlets that are audibly perceptible to some listeners in some systems, the differences in resistance that were indicated in the reference are very unlikely to be the reason. And even if there is a difference and resistance is the reason, the difference could work in either direction (good or bad), depending on the happenstance of the line voltage at the particular location and on the design of the particular components.

Regarding your mention of matching of metallurgy, that is outside of my areas of expertise and I have no particular comments.

Regards,

-- Al

Hi Dave,

Yes, I think we are pretty much in agreement at this point. Apologies if some of my comments came across as a poke in the eye; that certainly wasn't my intent.

I would emphasize that since the contribution to impedance that is caused by inductance ("inductive reactance," which is measured in ohms) is directly proportional to frequency, and increased inductance in the power wiring may therefore be helpful to some degree with respect to reduction of high frequency noise, that potential benefit may trade off against the ability of the power wiring to quickly respond to abrupt changes in demand for current. Such as the brief high current spikes we have referred to, which as I indicated may contain significant frequency components up to tens of kHz, or perhaps even more in some circumstances.

I would expect that concern to generally be greatest in the case of power amplifiers or integrated amplifiers whose output stages operate in Class AB or Class D, for which AC current demand fluctuates widely with the dynamics of the music.

Regarding the first question in your last post, I can't provide a knowledgeable answer.

Good one re taxes :-)

Best regards,
-- Al

06-21-14: Jazzonthehudson
To Almarg: as for reducing the resistance, should one consider soldering the joints additionally?

My guess is that use of a good contact cleaner would provide the same benefits (if any) that soldering would. As I indicated earlier:

The basic point to my previous post was to provide a quantitative perspective on the differences in resistance that were cited .... I believe that if in fact there are differences in the behavior of those outlets that are audibly perceptible to some listeners in some systems, the differences in resistance that were indicated in the reference are very unlikely to be the reason. And even if there is a difference and resistance is the reason, the difference could work in either direction (good or bad), depending on the happenstance of the line voltage at the particular location and on the design of the particular components.

Also, I would have some concern that applying enough heat to the terminals of an outlet for solder to flow properly, given that the outlet's internal conductors and the heavy gauge power wiring will conduct a good deal of that heat away, might result in internal damage to the outlet. Not something I would want to take any chances with.

IMO. Other opinions may differ, of course.

Regards,
-- Al