Power Cables

And from this thread, in 2010:

Almarg 9-15-2010

Power cords: a 2V drop across a power cord can rob a tube amplifier of as much as 40% of its output power!

Ralph, could you provide a technical explanation of why that would be so? I don’t doubt your statement, but I’m interested in understanding why that would occur.

Re your other points, all of which strike me as excellent, I think that it should be stated that none of those points NECESSARILY mean, to cite an example, that a $2,000 power cord will outperform a $200 power cord in any given system.

Atmasphere 9-15-2010

Al, the reason a power cord can have this effect is simple. If there is a 2 volt drop in a power cord, the filaments of the tubes will run cooler and the B+ will be reduced. Since this is a voltage, the result is we get less voltage output out of the amp. Less voltage=less power. Depending on the amp this can be pretty profound. and I have seen it with my own eyes. I do agree though that that does not justify a $2000 power cord, but it **does** justify one that has decent connectors and conductors that will not heat up at all. That has to cost something, probably not $2000 though. One thing about audio is that if there is a phenomena, there is also snake oil for it.

Almarg 9-15-2010

Thanks, Ralph.

That would also seem to say that the value of the ac line voltage at each listener’s location can be a very significant variable in the performance of a tube amp (assuming it does not have regulated filament and B+ supplies).

Which in turn emphasizes how easy it can sometimes be for extraneous variables to lead to incorrect sonic assessments.

Regards,
-- Al

Hey, how ‘bout an explanation how power cords can be directional? Or an explanation how they can’t would be fun, too. 😀

Pop Quiz: How come HDMI cables are directional?

Power cords are directional because one end is terminated to plug into the wall or power conditioner and the other end plugs into the audio equipment.  I can’t remember ever seeing one that wasn’t.

Really interesting that the article above says the wiring in the walls is usually pretty good.  

My Levinson 333 has no option to change the power cord.  I have wondered about running 30 amp service to it and swapping out the plug as specified in the manual.  I wonder if the difference would be audible for high-transient situations.

I have a couple of different power cords and look forward to trying them once my Stellar GCD arrives next week.

Why do folks insist that "Power Cables" need to have a bandwidth equal to that of a very high-spec amplifier’s audio bandwidth? Are you people INSANE? We are talking about 60Hz AC here!
If your power cords are carrying Khz range signals or noise there is something horribly wrong with your amplifier that needs to be corrected immediately, if not sooner because you are essentially operating a Radio Transmitter in violation of Federal Law! ;-)

I just measured the drop across the 5.5 foot original power cord on my 1964 Scott 222D Integrated Amp.  and found it to be 0.2Volts [120.8VAC at the outlet and 120.6VAC at the circuit side of the power fuse. This is with 18guage lamp cord!