[Dan Banquer]

Hi Nathan;
          Try Parts Express. www.partsexpress.com  They have numerous connectors of all types. I use the gold plated RCA connectors that sell for about $1.50 a piece. They are pretty heavy duty. There are more expensive alternatives, however jewelry looks better on my wife, not my cables.

[TheChairGuy]

I can't get enough of this topic!

I was a power cord sceptic until a year ago...for some reason I couldn't get myself to believe that a power cord could matter even a snit in the overall chain.  So, I went about upgrading various parts of my system irregardless of power cords.

Enticed by too much discussion about the subject, I made one myself.  I took 10ga. SJOOT wire, found an cheap IEC and a cheap Eagle-brand connector at Lowe's.  Cost well under $10.00.  While it sounded 'hashy', the music got bigger and fuller.

Looking for something at reasonable cost, I bought a used LAT International AC-2 cable for $95.00.  Wow - this stuff works!  I've since bought 5 more and have sufficiently cured that disease.  I've found each one added helped (the amps gained the most benefit), but less accretive benefit than the last.  However, this is how upgrades go - it's the law of diminishing returns at work.

Anyhow, the LAT's are terrific, though I've compared them to next to nothing audiophile.  10 ga., shielded, Marinco or Hubbell connectors, silverfuse wire, PTFE insulation and cheap by audiophile standards.

I think the $700.00 odd spent in the past year for PC's was as good an expenditure as upgrading this amount for a better... (fill in the blanks).

[audioengr]

Dan Banquer wrote:

A while back I measured the input inductance of some of my power transformers and found that they measured 50 Henrys on the transformers I use in the LNPA 150's. This inductance is across the AC line. I would greatly appreciate it if someone would enlighten me as to how a few micro-henry's of inductance in a line cord would make any substantial difference.

The difference in the transformer inductance is that this inductance is effectively in parallel with the load, not in series.  The cord inductance is in series.  Also, mutual inductance in the form of magnetic coupling virtually eliminates the effect of this inductance.

[audioengr]

Xi-Trum wrote:

Some amps come with *captive* power cords, i.e. power cords that are permanently attached (welded) to the amp at one end. In effect, the power cord is an extension of the power supply. For the experts out there, what are the benefits (pros/cons) of having the power cord as part of an amp?

The main advantage is that it eliminates one set of connectors, the IEC contacts.  Eliminating connectors is probably the single biggest improvement you can make in power delivery.  If you could wire the cable directly from the distribution box to the amp with no connectors, this would be ideal.

The disadvantage is of course, that you cannot try different power cords if they are not modular.

Therefore, the best compromise is to use copper or silver plugs, IEC's and power outlets to minimize the voltage drop.

[audioengr]

nathanm wrote:

What I don't understand is how come I can go to just about any hardware store and get household wiring for a few cents a foot, but the store-bought "audiophile" grade cables cost hundreds, even THOUSANDS of dollars? Isn't it all just copper? Is the hardware store stuff not oxygen-free enough?

I can only speak for my own products here, so here is my explanation: Good power cords (IME), must be low inductance and low loss, just like a speaker cable.  Therefore, they are just as expensive or even more due to high connector cost than a similar speaker cable.  The metallurgy must be single-crystal or similar in order to eliminate reflections.  The design must utilize low dielectric constant materials (Teflon, expanded Teflon, air).  In order to eliminate skin-effect, they must use multiple conductors.  My Magnum2 cord uses 36 conductors.  My new Grand Slam cord uses 19 conductors and takes 2 days to build a 6-footer.  Finally, they must use good connectors, preferably OFC copper, either silver or gold-plated.  This is why these cords are expensive.  It all makes a sonic difference.

[nathanm]

Hi Nathan;
          Try Parts Express. www.partsexpress.com  They have numerous connectors of all types. I use the gold plated RCA connectors that sell for about $1.50 a piece. They are pretty heavy duty. There are more expensive alternatives, however jewelry looks better on my wife, not my cables.

Yep, that's where I got all my speaker cable stuff.  I got the fancy dress extras at wirecare.com I think.  I bought the Dayton RCAs which were like 12 bucks for 4 of them.  Hey, I can appreciate fine metalwork, but 50 bucks for one plug is just way crazy for my budget.

[DVV]

Hi Nathan;
          Try Parts Express. www.partsexpress.com  They have numerous connectors of all types. I use the gold plated RCA connectors that sell for about $1.50 a piece. They are pretty heavy duty. There are more expensive alternatives, however jewelry looks better on my wife, not my cables.

Hear, hear!

Cheers,
DVV

P.S. My wife says Hi, Dan.

[Dan Banquer]

I would like to go back once again to the " issue" of inductance and power cords. Many of us use AC line filters for the removal of H.F. compnents that can get into the power supplies. All reputable AC line filters use series chokes (inductors) and shunt capacitors. As with many AC line filters they are usually common mode filters, The Dezoral is not common mode from what I understand, but does the job just as well. I use a 10 amp common mode AC line filter in the LNPA 150. The chokes in both the hot and neutral AC lines are 500 millihenrys each. Do I have transient power problems due to the series inductance? Absolutely not!!!! I have measured power, voltage and current with the amps doing 220 watts into a 2 ohm load at 20 khz, and no power supply problems were found. The test load cited above is way above what we will use on a day to day basis and represents a worst case test only situation.  The supply stayed in regulation.
Given a reasonably designed power supply with enough storage capacitance and a transformer that is rated for the power required, there is no reason that an AC power cord should be as low a reactance as a speaker cable. If that is not the case then it appears to be obvious to me that the amplifier is the problem, not the power cord!!!
Some audiophiles have found that certain power cords help them and some don't. Some of these cables have filters built into them, which is pretty expensive way of doing it, and some don't. Some are crosswired to flip the hot and neutral and some contain no earth ground where there should be an earth ground, and some use magnetic field to alter response.
All of the above things that have been done to power cords are band aids for the following. Poor AC line wiring in the home, not using a reputable AC line filter, the equipment has grounding problems, and acoustic treatment of the room leaves a lot to be desired.
Over the past few years I have been to demonstrations of the latest and greatest power cords. All of the "designer" power cords to date have given less dynamic range, more noise, and constricted response.
I am starting to get pissed off enough to start writing more about this is an article. I think that maybe one of projects this spring.

[DVV]

...

All of the above things that have been done to power cords are band aids for the following. Poor AC line wiring in the home, not using a reputable AC line filter, the equipment has grounding problems, and acoustic treatment of the room leaves a lot to be desired.

I second this 100%. It corresponds to my own experience completely.

Over the past few years I have been to demonstrations of the latest and greatest power cords. All of the "designer" power cords to date have given less dynamic range, more noise, and constricted response.
I am starting to get pissed off enough to start writing more about this is an article. I think that maybe one of projects this spring.

Ohhhhhhhhhhh, I'll join in if I can.

Cheers,
DVV

[Dan Banquer]

Thanks Dejan;
               I look forward to working with you on this. Your knowledge, writing and editorial skills will be a definite plus.
                 d.b.

[WorldWind]

DVV - Transam is correct.  I have found that with most customer systems, the power amp is the most sensitive to power cord change.  I have my own theory as to why this is the case:  The inductance is the issue.  Here is a technical explanantion and an example:

Amplifiers demand current from the power-line when the capacitors in their power-supplies become momentarily discharged due to high-current transients in the music signal. This discharge condition must be quickly recharged from the power-line, through the power-supply transformer, or a voltage sag will occur. Such voltage sags can cause audible distortion at the loudspeakers. If the power-line has significant series inductance in the path from the power panel to the amplifier, this can prevent the capacitor bank from recharging in time to prevent a voltage sag from occurring at the amplifier output transistors. With a low-inductance cable, the voltage drop across the cable will be insignificant during high-current transients, minimizing the voltage sag. This allows all of the current needed by the output transistors to be supplied when they need it, resulting in  fast, dynamic response to transient signals.

A typical 6-foot 14 AWG rubber cord and 25 feet of ROMEX has inductance of 7.2 uH and resistance of 235 mohms, ignoring the plug resistance effect.  Therefore, the voltage drop at 20kHz will be .....

That is as far as I can get in your post .... can you help me past this point? why you are using 20Khz here. are we not all using 60Hz in the US and 50hz. in the UK? the power cord is on the supply side.

[Dan Banquer]

Woldwind: I think you just answered your own question. The frequency is 60hz here and in the U.K. if I remember correctly is 50 Hz. The current "spikes" are another matter entirely.

[nathanm]

So let's say I'm using a big fat power cable and this is a good thing.  But aren't there much smaller wires used internally in the components? Do they negate the benefit?  Is the wire guage only as good as the weakest link? I always wondered what the point was in having heavy guage speaker cables because it all goes through those little bare copper wires in the speaker driver itself, right?  

If electricity works like plumbing (I'm asking, not telling) it wouldn't matter if I had a 6" pipe that could take 300psi if it gets converted down to a 1/2" pipe somewhere along the line would it?  Isn't the flow restricted to what the smallest pipe can handle?  Is it the same with electronics or not?

[DVV]

So let's say I'm using a big fat power cable and this is a good thing.  But aren't there much smaller wires used internally in the components? Do they negate the benefit?  Is the wire guage only as good as the weakest link? I always wondered what the point was in having heavy guage speaker cables because it all goes through those little bare copper wires in the speaker driver itself, right?  

If electricity works like plumbing (I'm asking, not telling) it wouldn't matter if I had a 6" pipe that could take 300psi if it gets converted down to a 1/2" pipe somewhere along the line would it?  Isn't the flow restricted to what the smallest pipe can handle?  Is it the same with electronics or not?

Time to get biblical on you, Nate. Remember the story of a father, showing his sons how easily a single twig can be broken, but how a bundle cannot? Divided we fall, but united we stand!

Same thing here. Sure one little litz wire can't carry much current, but put together 256 of them as in my own speaker cable (per side), and you have a cable capable of conducting well over 100 amperes. This in turn means that their individual impedances are parallelled, and if each was all of one ohm, what you left with is an impedance of 1/256th of an ohm, or 0.0039 ohms.

It doesn't work quite this way, but that is the general idea.

This is all based on the assumption that the designer was aware of his requirements and provided for them properly inside the unit. This leaves us with helping the power transformer to be able to draw as much as it needs, as quickly as it needs. This implies a low impedance, high current cable. It's hard to do an overkill in this field, because using heavy cables on such things as preamp transformers will also quickly demonstrate its benefits.

Nate, it's not in the absolute current capability, it's about speed. If your transformer is connected to the wall outlet by a massive cable, it will respond to power demands of it faster than when it is limited by a weedy, tortured intellectual cable, even if this was wound by virgins from a village south of the Andes, only on Saturday afternoons, and that if the wind was good.

To use your own words, don't let the power cable be the bottleneck, as it is far too often on commercial products.

Cheers,
DVV

[nathanm]

My theoretical question assumed that thicker IS better; but what I'm asking is - does it even matter when it's all got to to go through a little tiny cable somewhere?  I'm talking about the entire chain, not just the power cord on the amp.  

Say I've got a 10AWG cable going to my amp, well what's inside the amp?  Maybe a little piece of hookup wire going to the circuitboard?  Isn't all that nice 'bundling' gonna be for naught if it has to go through a "twig"-sized cable?

[jcoat007]

FWIW I met a guy that soldered his ac cable directly into his amp and said the improvement was tremendous.  

I have no first hand knowledge, just what he told me.

[DVV]

My theoretical question assumed that thicker IS better; but what I'm asking is - does it even matter when it's all got to to go through a little tiny cable somewhere?  I'm talking about the entire chain, not just the power cord on the amp.  

Say I've got a 10AWG cable going to my amp, well what's inside the amp?  Maybe a little piece of hookup wire going to the circuitboard?  Isn't all that nice 'bundling' gonna be for naught if it has to go through a "twig"-sized cable?

Nate, first the power for the whole unit has to get to the transformer, from which it is passed on to the rectifier and stabilizer circuits. The weedy little cables which come AFTER rectification and stabilization may be weedy and small, but there are usually quite a few of them.

If every little cable starts passing all it's supposed to pass, this will tax the transformer, which is expected to respond by delivering the juice. And how can it deliver the juice quickly if it is limited by an also weedy power cable?

And don't underestimate those little cables later on - each can pass substantial currents in peaks, which add up, and if the transformer can't respond quickly, what you have is limited dynamics induced by the power supply. Power supply limited, if you like - unfortunately, not at all a rare occurrence.

Therefore, it's wise to make life as easy as possible for the transformer, and therefore the whole power supply, on the input side, at worst you will ease the problem, at best you'll be rid of at least that problem.

Cheers,
DVV

[tmd]

nathanm,
It doesn't work the same as plumbing. The voltage drop over the path between lets say the wall outlet and the device is going to be far less with a higher gauge power cable that with a lower gauge. If you look at each part of the circuit as a resistor (for the purposes of voltage drop), to get the total voltage drop, you add all the resistances in series together and use V = I X R.
If the old cable had a resistance of .5 ohms and the new one has a resistance of .1 ohms, this will improve the overall resistance of the circuit, even if the six inches of cable from the IEC connector to the transformer in the amp has a resistance of 1 ohm!
I have way oversimplified the situation to illustrate the point. It isn't all about resistance (or inductance) and cable gauge but in my limited experience of power cords, higher gauge = better sound in general.
By the way, any fooling around I have done indicates that the benefits are most on the source, CD player and DAC and diminish as one goes further towards the speakers.
Neil.

[DVV]

nathanm,
It doesn't work the same as plumbing. The voltage drop over the path between lets say the wall outlet and the device is going to be far less with a higher gauge power cable that with a lower gauge. If you look at each part of the circuit as a resistor (for the purposes of voltage drop), to get the total voltage drop, you add all the resistances in series together and use V = I X R.
If the old cable had a resistance of .5 ohms and the new one has a resistance of .1 ohms, this will improve the overall resistance of the circuit, even if the six inches of cable from the IEC connector to the transformer in the amp has a resistance of 1 ohm!
I have way oversimplified the situation to illustrate the point. It isn't all about resistance (or inductance) and cable gauge but in my limited experience of power cords, higher gauge = better sound in general.
By the way, any fooling around I have done indicates that the benefits are most on the source, CD player and DAC and diminish as one goes further towards the speakers.
Neil.

Neil, agreed on all except the last sentence. I find that power amps gain the most (I refer to commercial products, not home brews), then the rest. I'm not surprised either, in my case they draw a lot of power, and that juice has to be transported somehow.

But I would agree with you in case somebody exchanges those really crappy power transformes usually included in CD players, tuners and such like, with decent toroids of some power (e.g. exchanging a 2oVA frame for a say 50 VA toroid which is also well made, i.e. low loss).

Just my view.

Cheers,
DVV

[BlackCat]

A lot of double E talk in here - too much for a poor software engineer, power cords are a hardware problem.  This is how I want to address my power cord situation.

1. Purchase a PS Audio Juice Bar
2. Power the Juice Bar with a Shunyata Research Sidewinder
3. Buy Furutech connectors
4. Buy "Bulk" Harmonic Tech single crystal copper wire
5. Build short (1.5 feet) power cords from above components
6. Plug components into Juice Bar using constructed cords.

I can get the Furutech connectors and single crystal copper wire from Bob at audionut.com for around $20 each for the connectors and about $12/ft for the wire.

Whaddya all think of this approach?