What is the best geometry for PCs? Are there any guidelines you guys have noticed, like configuring the geometry for low inductance? It seems I mostly see twisted pairs and sometimes star quads, which are low inductance, esp. the star quad.
I have made a few PCs with twisted pairs of 12g mil spec, now I have some 14g vintage WE cloth covered wire coming that I'd like to make a few PCs with. I'm thinking a litz braid maybe.... if you use a litz braid with 3 legs, would you include the safety ground in the litz braid or use 2 runs of neutral wire and keep the safety ground outside the litz braid?
Any suggestions are appreciated... :thumb:
I can't say much about conductor geometry, although I understand how it works and believe that it can have a significant effect. I am more swayed by the materials chosen for the conductor and dielectric. Hearing wires made with JPS alumiloy conductor have really impressed me, so I put more weight on that. But JPS may also be using winding geometry that adds to the effect.
I'm very happy after building these.
http://www.audiotweaks.com/diy/bobcrump_pc/page01.htm (http://www.audiotweaks.com/diy/bobcrump_pc/page01.htm)
The Asylum cord was my go to cord for quite a long time, besting a lot of others I tried. And it can't be beat for the price.
However I chaned my mind after hearing them vs both the Kaplan cords and the Triode Wire Labs cords. Yes, it is more money for those, but they both are much better.
I'm sure the Asylum cord is great, but I don't want to buy Belden wire, I am constructing my own cable out of 14g NOS WE wire. I believe better performance will come from geometries other than the standard twisted 3-wire configuration of most manufactured powercords.
It seems TWL is popular here, their website says it is litz construction...
Another PC question, does the safety ground leg contribute to the sonics?
Hello
I don't think this question can be answered. There is too much criteria in pc placement to answer it. The question is too general.
The question doesn't ask if noise reduction is the motive or is it power response? It doesn't ask where the pc is going and what is allowable in sound staging. Do we want a stiff presentation from the source or do we want to color it? I really don't know the answer to my own questions as far as geometry,but that is where I would like a question like this to go as far answers.
I am going for as neutral as possible, a touch on the warm side is ok. My amp is a low power (5-6 wpc) SET amp, tube preamp, source is a USB DAC. I also use a SurgeX surge protector and line conditioner that needs a new PC, it has a captive cord with a nickle plated male plug. I might just replace the plug though, IDK...
I'm thinking of doing a 4 wire litz braid with the hot and neutrals paired with their own ground wires.... should balance inductance and capacitance while providing good noise rejection.
What is litz?
This is a 4 wire flat litz braid...
http://www.chimeralabs.com/diy_braid.html (http://www.chimeralabs.com/diy_braid.html)
I actually used a helical braid instead of a flat braid... if you can imagine 2 intertwined criss-crossing pairs of wire at a 90 deg angle to one another along the long axis, that's what I did... OK, I will take pics when I get it done. :-P
I think... or maybe better said is I hypothesize that the geometry of a PC is very important and on the level of materials and connector quality. So, I would guess the PC can act as a filter, depending on it's geometry.
Here's a couple pics of the finished cord. I tried it briefly on my SET amp and it was a little clearer but not as full sounding and a little closed-in on the soundstage... but that's with ZERO break in so I think it will open up and improve a lot.
I have material to make one more... might try a different geo and see what happens.
(http://i99.photobucket.com/albums/l318/davec113/Aikido%20Preamp/powercord8-9-12001.jpg)
(http://i99.photobucket.com/albums/l318/davec113/Aikido%20Preamp/powercord8-9-12002.jpg)
I just put my PC on my DAC, which was using a stock PC w/ a nickle plated male plug.
This made a pretty big difference. I did not try one of my 12g twisted pair mil spec cords on the DAC for comparison yet, I will give the new PC a chance to break in for a couple weeks.
Also, here's a helical litz braid, as done by Shunyata... I have a Jupiter IC using 8 strands of 26g 6N copper and it is a very, very good IC. Here's links to both:
http://www.shunyata.com/Content/technical-HelixGeometry.html (http://www.shunyata.com/Content/technical-HelixGeometry.html)
http://jupitercondenser.com/Cable/cotton-insulated-cable.html (http://jupitercondenser.com/Cable/cotton-insulated-cable.html)
Dave the concept of a good PC is deliver more current with less noise. LCR is important in determiming the character of the sound. Windings of such can affect the outcome. As well as grounding schemes. Some designers like the ground wire twisted with the hot and neutral, others run the ground outside the wind. Then there is the Ga. of the ground wire. Should it be of a smaller or larger Ga. ? Ah the 66 million dollar question. The wire itself wether concentric wind, stranded, ribbon or solid core. Then there are designs with multiple conductors of different types. Annealing of the wire appears to great affect on sonics as well.
so it appears not an easy task to get it right. Experimentation and measurement is key to any design. Trial and error.
Now with all that power cord "A" will not sound the same with different components. The power supply of such is a major factor as to what the PC will do.
Just remember one size does not fit all. As of this writing we are using a combo of cords to achieve sonic nirvana. All TWL Labs on components and Omega Mikro Active on the UberBusses.. Waiting for two more TWL 7+ cords to compare directly to the Omegas. The Omegas in the components do not achieve the sonics of the TWL cords. Just too bright. In the Uberbuss compared to theTWL 8Ga cryoed we preferred the Omega. Why does that combo work out better for us ? I just do not know.
As an aside the addition of the second Uberbuss to the system, one for amps and one for all else was a win win. Better than ANY powercord combo tried.
Last but certainly not least is maintaining bright and shiny contacts. A clean connection is a good connection. Progold for all.
charles
Thanks rollo.
One thing that has me a little baffled is the difference between neutral and ground as far as how they would interact with the power wire and produce different LCRs. Neutral and Ground are connected together at the main panel and both go to the same ground point, either a stake or a copper water line. But I suppose the neutral is really used as the "return" and ground just as a safety... so it would seem to me that neutral would be the wire to reference to the power wire and safety ground could be left outside the main geometry. This is how I made my 12g twisted pair PCS, the ground counter-rotates around the twisted pair of hot+neutral.
I made a star quad using exactly the same wire and connectors as my 4 wire litz braid, should be interesting to compare them... I'm also going to try running the PCs as 2 wires for hot, 2 for neutral, and an exterior ground wire instead of their current configuration, which is red wires are hot and neutral, black wires are both grounds.
(http://i99.photobucket.com/albums/l318/davec113/Aikido%20Preamp/DSCF4870.jpg)
Here's a link to a discussion on this very topic over at AC
http://www.audiocircle.com/index.php?topic=10004.0;imode (http://www.audiocircle.com/index.php?topic=10004.0;imode)
Quote from: rollo on August 15, 2012, 08:06:22 AM
Dave the concept of a good PC is deliver more current with less noise.
I was just thinking the increase in dynamics we commonly perceive in good PCs is the result of a high current slew rate ability. The voltage drop across any reasonably sized PC is going to be nearly identical, but there may be a BIG difference in current delivery rate of change due to the propagation speed of the wave in the wire.
It is said that the electrons in our wiring moves at the speed of light, but that is not the truth. The LCR of the cable affects the propagation speed, and while many cables may be near the speed of light, a super low inductance ribbon cable (Goertz) might have a propagation speed only 1/5 that of light.
So, I think some balance of noise rejection or filtering, along with high propagation speeds are key. Also, this explains why larger diameter conductors usually sound better, it's not that the wire is not capable of supplying the correct voltage and AVERAGE amperage, it's that a larger diameter wire is capable of a higher current slew rate vs. a smaller diameter wire.
Because of this, I am thinking when I modify my power cords to have two 14g wires for hot and neutral vs one, it should make for a slight improvement. And probably more of an improvement in a power amp vs. a source component... I think this is why different PCs are best in different components, it depends on whether current slew rate or filtering will be a bigger advantage.
It is telling that no "industry" types have replied... I think that anyone can buy the same receptacles and connectors but it's the geometry that makes the difference between a decent cord and a great cord.
A great cord to do what? Any power cord will power your system. But there is no criteria here. Where is the strategy here? Power cord placement and ic placement are used in accenting a person's personal sonic identity. Thats what makes cords and ic's so appealing. Some are fast and some are colored, some cords lift bass off the ground while others give you fat bottom clear bass sounds. All are competant designs. Creating a very a low impedance connection sounds great and works but it may not be what i would want as a main motive, specifically with a particular component feeding a particular speaker.
Oh and i think its cool you are building your cables btw and posting pics. :thumb:
Quote from: Werd on August 20, 2012, 04:55:10 PM
A great cord to do what? Any power cord will power your system. But there is no criteria here. Where is the strategy here? Power cord placement and ic placement are used in accenting a person's personal sonic identity. Thats what makes cords and ic's so appealing. Some are fast and some are colored, some cords lift bass off the ground while others give you fat bottom clear bass sounds. All are competant designs. Creating a very a low impedance connection sounds great and works but it may not be what i would want as a main motive, specifically with a particular component feeding a particular speaker.
Oh and i think its cool you are building your cables btw and posting pics. :thumb:
At this point I don't know, which is why I started this thread... I was looking for recommendations on PC geometry. But I haven't got much feedback so I'm doing what I can. At this point I have a hypothesis, but testing that hypothesis is probably more trouble than I want to go through, so I'm putting it out here for discussion.
I think for source components the filtering ability of the PC's geometry is probably somewhat more important than low impedance. For amps and preamps, I'd guess that a lower impedance geometry that would give you high propagation rates through the cable would be best, which would also mean large gauge conductors to minimize R.
To do any meaningful test I would have to build and test a lot of cables, which as I said, I don't want to do. I'd rather have someone who has done it already tell me what they think.
I'm actually of the opinion that the connectors at the end almost make more of a difference than the wire itself, as long as you are using sufficient gauge.
Quote from: BobM on August 21, 2012, 05:28:25 AM
I'm actually of the opinion that the connectors at the end almost make more of a difference than the wire itself, as long as you are using sufficient gauge.
I agree that the connectors are very important. Actually, my old boss did a study about PCs in one of his past jobs, which involved a lot of very precise TIG welding for an instrument manufacturer, and determined connectors were the most important factor.
But I think in audio, the geometry is also an important factor, as it can affect impedance and noise rejection/filtering, which will in turn determine how the PC "sounds". Anyone can buy and use the same connectors as anyone else, but geometry is much more variable. Also, connectors get very expensive beyond the entry level Wattgate stuff or similar, and I'm not up for that. I also can't figure out how Wattgate can charge double or triple the price for the same entry level connector with a gold or silver plating. It doesn;t cost that much, and I'm not sure there is any benefit vs. unplated brass. Sure copper would be best, but I don't think anyone is making AC receptacles out of pure copper, it just wouldn't work using conventional receptacle design. Plugs maybe, but still too much $ for me...
Dave there appears to be many ways to skin the proverbal Cat.
There is no best just different. There are so many areas to consider such as harmonics on the line, resonance, wire type [ ribbon, stranded, solid core, all of the above] , connectors, shielding, dielectrics, type of connection [ soldered , crimped ] etc.
I think what is more important than winding is the "overall design". One size does not fit all.
It would be helpfull if measurements were correlated to sonics. Voicing of powrcords can be achieved by the wire Ga. of the ground wire alone. Go figure.
Different winding techniches have different LCR and propagation measurements. Which one is desirable for what components power supply is the 64,000 question.
BTW do you really think a powercord manf. would give input on your DIY project ? R&D costs time and money which is key to their final product and sales. Maybe some general info might be expected but that's it.
charles