audiphile power cords

Do upgraded power cords really make a significant difference in sound quality? I have a Jolida 502p that I think sounds pretty good. What do you recommend for a power cord that would make a significant improvement?

Showing 6 responses by atmasphere

If anyone would like to know why power cords make a difference, I would be happy to contribute. BTW I have some measurements to back my claims.
Please do Ralph!


With power cords its all about voltage drop across the cord. Some of that is at 60Hz, and some of that is much much higher- well above 30KHz-100KHz depending on the power supply in the unit with which it is being used.

I've seen a 2 1/2 volt drop rob an amplifier of about 30% of its output power. The cord was rated for 10 amps, and the draw was about 6 amps. This measurement was done with a simple 3 1/2 digit Digital Voltmeter.

The more insidious problem is high frequency bandwidth. The power supplies of most amplifiers have a power transformer, a set of rectifiers, and a set of filter capacitors. The rectifiers only conduct when the power transformer output is higher than that of the filter caps. So:

When the caps are fully charged the amp is able to play. As it does so, the caps are discharged until the AC line voltage waveform gets high enough again that the rectifiers in the power supply are able to conduct. Depending on the state of charge of the filter capacitors, this might only be for a few microseconds or it might be a few milliseconds. Either way, the charge is a spike which has very steep sides- and requires some bandwidth to make it happen.

If the power cord has poor high frequency response, it will current limit on these spikes. This can result is subtle modulations in the power supply or even a sagging power supply voltage.

Romex wiring found in many buildings actually works quite well. So it really becomes all about that last few feet and also how well the power cord is terminated- molded cords generally are not terminated very well. If the ends of your power cord get warm after a while, you know you have a problem!

This can be measured, its quantifiable and also audible as many audiophiles know. Anyone who tells you differently probably has not bothered to do any measurements- please refer them to this post.

I can go into more depth but this is it in a nutshell. Incidentally, Shunyata Research is refining an instrument that does a more in-depth analysis of what this is all about. At the link you will see that their tests essentially confirm what I have said here.
^^ They are all important. I have to say I have not studied the matter enough to know how they all weigh out. I do know though that its harder to build the cable to have good HF response and also keep it flexible, which is required by law (you can't use ROMEX in a power cord for example).

I have seen the conductors heat up too. So its pretty obvious that every part of the cable has to work correctly!
If a simple power cords can improve the quality of sound to the extent that it warrants its exorbitant price tag, why would you not (as a designer and seller of amplifiers) sell your amplifier straight out of the box with such a power cord.

The problem is that there is a very good chance that the power cord will be dumped in favor of another. This is why we have always had IEC connections on our products, so it is possible to audition power cords. FWIW, on our MA-2 we actually have 2 separate AC circuits, using 2 power cords. This was done to minimize the effects of the AC wiring both inside and outside the amplifier. That feature was designed into the amp in 1990.

The power cord is never being used as a filter BTW. I can only describe that idea as mythology.

Regarding the readings that Shunyata had in that article, I think it would be very interesting to test some common cords on there, like certain models of Belden. I think that heavy gauge is usually a good place to start- install some decent connectors and you are usually well on your way. However if you think about it, just doing that and selling it at a normal markup will result in a power cord that costs at least $150.00- maybe more like $200...
Rleff, We have had good results with Synergistic Research, Purist Audio Design and Shunyata Research, for starters...
Phd, please go back and reread some of my earlier comments and you will see an answer based on measurements as to why power cords make a difference, which includes tube and solid state amps.

Ketchup, I'm with Al on this one: I don't recommend having anything to do with a power cord made of ROMEX!!