[Al Garay]

Larry,

I thought you prefer not to use an IEC and wire directly. Did I misinterpret your message at the top of this page?

Which Schurter IEC are you referring, chassis connector or female plug?

thanks,

Al

[tianguis]

Al:
       I haven't gotten around to wiring direct to the PS yet, but I'm sure it will sound better. I was referring to the Schurter female plug.

Regards,
Larry Welsh

[tianguis]

If you aren't all bored with my tiny saga, read on.
Today, I modified 5 Volex PC's with P&S 5266XHG's. I removed all my old PC's and moved the Transcendent BPS so I could use a 6' PC, rather then the DIY 8' I was using. I replaced all the PC's with the modded Volex's.
The instantaneous effect (using digital sources) was much larger soundstage and frequency neutrality. The bass bloom is gone (though it was fun) and everything sounds more accurate. Harry Pearson's "blattiness factor" has increased significantly, due to lower-mids detail.
The most radical change was to my Hagerman Cornet phono pre, which I listened to last night with an un-modded Volex. The thing has come alive in the lower bass and the soundstage has grown spookily.
I ordered 5 Schurter IEC's from Allied today. Pain in the butt to assemble, but probably worth it.

Larry Welsh

[Occam]

Larry,

Dude, you're killing me. You replaced the plugs on all 5 of your Volexes? You didn't  leave one with the original moulded plug for comparison purposes?  I can't fault you as someone seeking to improve their system, but as a former pedantic lab dweeb, you're driving me up the wall You don't think even one of the original moulded wall plugs wouldn't add a subjectively pleasing amount of bass plumminess for your low Qtc Lowthers?

It ain't a real Bob Crump approved 'Asylum' cord unless it uses the Schurter 4300.0603 IEC plug assembled as follows -
http://www.tubeaholic.com/projects/page.view?RowId=54

Looking forward to your comments on your continuing mods.

[Marbles]

Larry, you're making me feel pretty good...I have an Asylum Cord made by Kevin P Haskins (DIY Cable) and approved by Bob Crump on my Cornet

It sounds good to me...

[tianguis]

Occam, Marbles:
       I thought I'd done them all but I just found an un-modded one. I'll P&S it first thing tomorrow. I lost count when I put a P&S on the Wiremold strip. Dpn't need no steenking plums. The Schurters I ordered are, indeed, the 4300.0603 (found another in my stash). Of course, I'll solder them.
       Yup, I've got lots of stuff approved by B. Crump, but mainly cigars and booze. My tubed components, though, aren't approved by Bob.

Regards,
Larry Welsh

[Occam]

...I thought I'd done them all but I just found an un-modded one. I'll P&S it first thing tomorrow. .....

Please, noooooooooo! Leave one of your Volexes virginal and in a few weeks do a comparison of that Volex to your present incarnation of powercord. Sometimes it very informative and educational to revisit an oldie but goody....

[tianguis]

Occam:
       Happy April Fools Day.

Larry

[Marbles]

Well, you got me too  

[JoshK]

Occam:
       Happy April Fools Day.

Larry

 

[Occam]

Lordy, I'm thick.....

[Occam]

Larry,

I'm curious as to your comparitive evaluation of the Volex IEC vs. the Schurter, and an elaboration on the replacement of the wall plug.

I spent yesterday with Josh evaluating the worlds heaviest Volex powercord.
(This is the Sarah Lee approach to powerconditioning, an anticipated DIY project that is so kickass, it is a legend in my own mind....)
As we optimized both the architecture and componentry, those powerconditioning benefits manifested in spades (a brignter smile, maximum groovosity, blacker blacks, increased virility....) , but moreover, in addition, as the resolution and benefits increased, it sounded more and more like Volex; just moreso.  So, at some point when we're finished playing slap and tickle with the conditioner part, we'll have to circumcise those plugs.....

[tianguis]

Occam:
        I don't have the Schurters yet. As soon as I do install one, I'll post.
        Spent today tuning a Teres 340/ Schroeder Reference/ Allaerts/Nagrs pre/Manley 300B Neo-Classic 300B/Sonus Faber Amati Homage system today. Unfortunately, I only brought one Volex PC! That'll learn me.
        I don't pay attention to some details, like active speak cables with blue LED's the size of Pythons (the cables, not the LED's). It sounded considerably better (according to the owner and myself) when I was done. The 25 year old single-malt may have had something to do with that, but I'm not convinced.

Larry

[andyr]

Hi, Paul,

I read your description of the Volex PC as having an overall shield.

I am wondering:

a) what is the point of having shielded PCs when the rest of the house wiring is unshielded (I understand some of you folk in the USA have your house wiring inside earthed metal conduit? ... we certainly don't in Oz!)?

and

b) what are the pros & cons of shielding each core (ie. A, N & E) vs. shielding the overall 3-wire cable like the Volex does?

Now I agree with your concept ... that the Volex provides a good, basic, inexpensive product. As you say, other PCs may be better but they will no doubt cost more!

One point I can think of, that a "good" PC should have (apart from the obvious ... thick conductors to minimise resistance), is low inductance - again, to minimise any dynamic force acting against the current flow ... particularly as it happens in milli-second, high-current bursts!

I wonder if the Volex is tightly twisted inside? I suspect if one got hold of the same guage, mains-rated wire as in the Volex and simply braided the 3 wires together, you would end up with a PC which has lower inductance - and is therefore, theoretically "better"!!

Of course, if your answer to my Qu a) above is that the shield on the PC DOES do some good, then the additional work needed to put a shield over the top (earthed at the wall-plug end only!) means making up your own PCs is quite a chore!

Regards,

Andy

[Occam]

a) what is the point of having shielded PCs when the rest of the house wiring is unshielded (I understand some of you folk in the USA have your house wiring inside earthed metal conduit? ... we certainly don't in Oz!)?

Thats an awkward question for me to answer. I live in the Nasty Apple where non-metalic conduit/wiring was only approved in the last 10yrs. NYC has their own specific codes that are influenced by a strong electricaians union, whos goals are not neccessarily guided by technical issures. All of my wiring is within metalic conduit.
About 5 years ago, when I first started mucking about with PCs, I bought some Volex 17504/5 which are equivalent to the shielded volexs, but have no shield. My subjective prefference was for the shielded versions, But my system was (I hope) far less resolving at the time, and I should revisit those unshielded cords.

b) what are the pros & cons of shielding each core (ie. A, N & E) vs. shielding the overall 3-wire cable like the Volex does?,,,One point I can think of, that a "good" PC should have (apart from the obvious ... thick conductors to minimise resistance), is low inductance - again, to minimise any dynamic force acting against the current flow ... particularly as it happens in milli-second, high-current bursts!

I believe its a tradeoff between actual physical construction and associated electrical parameters. Ideally,one would want the line and neutral wires in intimate physical contact to maximize capacitive coupling/ minimize inductance. One way of increasing these measures is a star-quad or multiple twisted pairs. But as soon as you put a shield over it, you face the problem of increased capacitive coupling to ground, which increases (more than?) linearly with the number of line-neutral wires. This would require very large spacing between those line-neutral wires and the shield (a 'firehose'), and a rather robust shield if that shield is to serve as the ground as well, i.e. a copper braid instead or in addition to the metallized mylar, or an additional external groundwire .
I believe this is the reason that many bespoke cords forgoe shielding and rely upon the interference rejection qualities inherent in star-quad and multiple twisted pairs, and simply counterspiral a thick ground wire external to the internal line-neutral agglomeration.
As far as individually shielding the individual lines..... dunno. That would require far more work/research that I'm willing to spend on the issue.

I wonder if the Volex is tightly twisted inside? I suspect if one got hold of the same guage, mains-rated wire as in the Volex and simply braided the 3 wires together, you would end up with a PC which has lower inductance - and is therefore, theoretically "better"!!

In the Volex cords, their 3 wires are cabled (with more than 2 wires you call it 'cabled' rather than 'twisted') at about 6 twists/foot. From a 'thought experiment' (non empirical) perspective, I see no merits at all to actual braiding. The increased capacitance/ low inductance of multiple twisted pairs and star-quad conguartions appear far more appropriate.

And throwing yet another sabot, the lucky happenstance of the Volex's 'adequacy' for my 120V mains, might be farther from optimal for your 240
Volt mains, as along with the voltage doubling, the current flowa halve.

Frankly, the idea of going to the hassle and expense of importing these Volexs to Australia and refitting a different plug strikes me akin to taking coals to New Castle. Start with something that IMO is a step beyond what the Volex has to offer. Start with a 4wire cabled cable (star-quad) that had properly specified wires as well as characteristics that yank your audiophile monkey bone, and counterspiral a heavy ground wire around the outside insulation. You'd be surprised how many of the well thought of audiophile cords are exactly that.
In doing this you might well be violating a myriad of Australian electrical codes, dunno....

[andyr]

Hi, Paul,

I totally agree with you when you say: "I believe it's a trade-off between actual physical construction and associated electrical parameters".

However, I find it interesting that you go on to say: "Ideally, one would want the line and neutral wires in intimate physical contact to maximize capacitive coupling / minimize inductance".

The way I look at it, you certainly want the line/live and neutral wires to be in close physical contact ... but this is to minimise INDUCTANCE, as the lower the inductance is, the less the AC current down these wires is inhibited.

Unfortunately, as a direct result of this close physical contact, in lowering the inductance ... you increase the capacitance - so it is indeed a compromise!!

Basically, this is a bad thing but high capacitance in a PC does not compromise it as much as high inductance does!!  So, yes, it's a trade-off but one which is "slanted" towards the benefit of low "L".

There is a PC design on the Web put out by Alan Maher which suggests two twisted pairs - one active/earth and the second neutral/earth.  Of course, the two earths are connected at both ends.

To my way of thinking, what this does is produce a PC with very high capacitance (as each "important" wire is twisted with an earth) but not very low inductance (as it's the close contact between the active and the neutral which lowers L!!).

In contrast, braiding the 3 wires results in a low inductance because the active and neutral are in close physical proximity (hence braiding is popular for speaker wires!!), with only a moderate amount of capacitance arising from the proximity of the earth wire.

And BTW, braiding would result in the active wire being wrapped around the neutral wire about 20 times per foot, not just 6 per foot!!

Theoretically, I can understand that if you made up an alternative cable which had active & neutral tightly twisted and, as you say, the earth wire counter-spiraled around it, this might result in a more optimum configuration as far as L & C are concerned ... but I think it would be a bit harder to make up.

Whether the latter would be better than my braided PC, from a noise rejection POV, is a matter of conjecture ... however, I agree with you that having an overall shield on my braid will certainly increase the capacitive coupling to ground, which is NOT a good thing!  So it may NOT be a good idea to use a shield because of the extra capacitance it brings with it!
NB: Yes, if you space the shield a very long way away then the resulting capacitance is minimised, but "fire-hose" PCs are not very practical!!

And so, I may have just argued the solution to one of my questions!! ... using 3 individual shielded wires must surely a) increase the overall cable capacitance and b) increase inductance, since the active and neutral wires are further apart!

Regards,

Andy

[Occam]

Andy - I believe our disagreement is the result of my failue to properly explain the nature of capacitive coupling in a powercords. That capacitance appears in shunt between conductors, line-to-neutral, line-to-ground. and neutral-to-ground.

Empirically, I've found any coupling to ground to be a bad thing, whether it be the result of a shield in intimate contact with conductors, or a shielded cord with increased to ground coupling due to the additive nature of capacitance and multiple conductors. I simply don't like to put noise onto the ground, whether on a powercord or conditioner, when there are more effective measures. I don't use Y caps on my power conditioning for that reason.

Which leads me to line-to-neutral capacitance. This is simply 'accross the line', X capacitance.  This is not series capacitance, but a frequency dependant highpass restisor, which simply takes whatever high frequency noise that passes through, and makes it common mode,  hopefully to be dealt with by the transformer, or in the case of a switching mode ps component, its common mode choke, residing withing the fed component.

While you can plausibly argue for minimizing inductance, I see no downside to the usually associated result, increased shunt capacitance. And unless you've a line neutral configuration consisting of 10+ twisted pairs, you need a rather long cord to get in the nanofarad range. I simply don't see any technical benefit to not increasing shunt capacitance while minimizing series inductance.
For an additional reason, I consider a star-quad line-neutral, external counterspiraled ground powercord, the 'Sarah Lee' of DIY powercord topologies.  One could argrue for more twisted pairs to further decrease inductance and increase capacitance, but let us examine the nature of the resulting inductance.  Just as its geometry rejects external noise, and minimizes its radiated field, its residual inductance cancels when presented with antiphase signals, exactly what you want in a powercord, and when presented with a common noise mode signal, that inductance is additve. Its a low valued comon mode choke, a CMC.

Do these minimal optimizations of powercord characteristics help? Dunno, but I'll respond with one of my tangental anecdotes -

On my 30th birthday, I visited a dear highshcool friend, and as we did on such occasions, got quite loaded. We walked outside to await our ride from my wife and his ladyfriend. I stopped, and quite profoundly asked -
"Do you wonder what your life would be like if you could suddenly 'transport' your life to somewhere that nobody knows what a doofus you are?"
Pondering for an additional moment, I opined - "Wouldn't help..."
To which my friend responded - "Wouldn't hurt"

[andyr]

Andy ... I simply don't see any technical benefit to not increasing shunt capacitance while minimizing series inductance ...

Hi Paul,

That's great - I thought it was a case of "robbing Peter to pay Paul"  

And if you say "Empirically, I've found any coupling to ground to be a bad thing ... the result of a shield in intimate contact with conductors ..." then I would surmise in Oz, where house wires are just strung in the wall cavity - with no metal conduit - there is little benefit to be gained from having shielded PCs.  Leaving off the shield will reduce capacitative coupling to ground in the PC, compared to a shielded PC, which is a ggod thang.

This means that, yes, your description of a good basic PC design as having an active/neutral twisted pair with a outer spiralled ground will probably deliver lower ground coupling than my idea of a straight 3-wire braid.  However, braiding is pretty easy to do, so it might only result in a tiny difference in PC efficacy.

Regards,

Andy

[Occam]

Andy - Just a quick addition. The reason I think the star-quad unshielded cord to be the 'Sarah Lee' of DIY powercords is that its so durn easy to implement.  Any cabled 4 wire powercable is basically star-quad. Its got an outer insulation so your counter spriraled ground is spaced away from the line and neutral wires. The rational for spiraling in the opposite direction of the inner star-quad is to additionally minimize 'to ground' capacitance as the intersection between the ground and inner wires is more perpendicular than parallel.  So you take a bog stock 4 wire power cable, spiral a 12ga ground wire around it arse backwards, cover it with sexy techflex, and voila, something amazingly like a large number of commercial bespoke cords.

And those memories of braiding 'gimp' keychains and suchlike at sleepaway camp nigh on 40+ years ago, still give me nightmares

For a (IMO) humorous retrospective -
http://db.audioasylum.com/cgi/t.mpl?f=cables&m=72204
(my evil twin persona is 'pmkap')

[daj]

Large conductors only matter for large currents, and 18 ga is fine for up to 10A (1250W). You can save beaucoup by getting the Volex sheilded cords with smaller conductors, at about $7 vs. about $20. Also, Mouser has the Volex products cheaper than most places. As of now, http://www.mouser.com/catalog/629/886.pdf or search www.mouser.com for 686-17725