Subversive DIY Speaker Cable

DVV · « **Reply #120 on:** 16 Mar 2003, 08:36 am »

Quote from: JohnR

Um... can you explain what you mean by "sheer conductivity"?

Well John, if you take so much say copper as you need to be able to pass a certain current, and if you use stranded wires, it will have a certain diameter. But if you want it all nicely laid out so that the cable is not round but thin, the same amount of copper will need to be much wider if it is a lot thinner.

Essentially, I'm primarily interested in a cable's ability to pass along many amperes of current, or put in another way, I want its overall internal impedance to be as low as possible. All other things being equal, this requires many strands and hence a thick round cable, or a flat one with a very large area for the same amount of copper.

Granted, you can do things to make it a still better conductor, such as using superior copper, silver plating it, using composite materials, even going all silver, and then monocrystal, but all this will not increase current conductivity by an order of magnitude. Thus, you are still left with sheer physical size, and in that domain, I have yet to see a flat cable capable of competing with the one I'm using now.

Cheers,
DVV

Dan Banquer · « **Reply #121 on:** 16 Mar 2003, 01:54 pm »

Dejan has once again made an excellent point.

JohnR · « **Reply #122 on:** 16 Mar 2003, 05:27 pm »

Let's keep it simple. Suppose that a piece of wire has a cross-sectional area of 5 mm^2. Please explain to me (in technical terms please):

1. How the wire has more conductivity if it's made out of strands instead of being solid.

2. How the wire has less conductivity if it's shaped to be flat instead of round.

Dan Banquer · « **Reply #123 on:** 16 Mar 2003, 07:16 pm »

John R: I see no difference in "conductivity" between two wires of different shapes, as long as they have the equivalent crossectional area or let's say AWG. The main advantage of multistranded wire in this application ( speaker wire) is flexibilty and ease of use. To the best of my knowledge most speaker wire using this type of construction also has lower impedance across the audio band.
Now I have a question for you. Since you are a DIY guy and do a lot of work with loudspeakers, have you ever opened up a tweeter and examined the wire used in the voice coil of a tweeter?

JohnR · « **Reply #124 on:** 16 Mar 2003, 07:46 pm »

Correct. So in that case, to what do you attribute this lower impedance across the audio band of the stranded wire? Are you saying that a stranded wire has lower inductance than a solid wire of the same cross-sectional area?

How about the flat wire -- does a stranded wire have lower inductance than a flat wire with the same cross-sectional area?

I haven't been fortunate enough to destroy a tweeter, and in fact the tweeters I've been using lately don't have voice coils...! But I would assume that the coil is wound using a fine-gauge magnet wire.

DVV · « **Reply #125 on:** 16 Mar 2003, 08:03 pm »

Quote from: JohnR

Correct. So in that case, to what do you attribute this lower impedance across the audio band of the stranded wire? Are you saying that a stranded wire has lower inductance than a solid wire of the same cross-sectional area?

How about the flat wire -- does a stranded wire have lower inductance than a flat wire with the same cross-sectional area?

I haven't been fortunate enough to destroy a tweeter, and in fact the tweeters I've been using lately don't have voice coils...! But I would assume that the coil is wound using a fine-gauge magnet wire.

John, you are missing the point.

Let's take my own cable as an example. It has 256 1 mm strands rolled up into a round shape. There is no obstacle that I can see why you shouldn't have those same strands laid out side by side, except the rather obvious - in that version, the cable will be considerably wider, but will also be much thinner.

As far as I can see, the only issue which may appear in the side-by-side configuration is that of the isolation's surface now being in contact with every single wire, and hence the skin effect may present some new aspects (or may not, as far as I know).

However, since you are using the same material, in the same form, but simply repackaged, the fundamental electrical characteristics of those two cables should be the same. Thus, only their form is different.

Another possibility is to strip my cable bare for a say 1 meter and weigh the conducting part of it, smelt it and turn it into an equivalent 1 meter strip of single thin wiring. In both cases, it's the same material, with the same charactieristics, and should be electrically the same.

However, my experience shows that flat cables get to be flat primarily by using less copper or whatever conducting material. I'm not sayin all of them are like that, but I am saying most are like that.

Ultimately, you can always take a meter's worth of several cables and measure them for impedance, inductance and capacitance; that should take care about the conductivity part, which is a physical value. As for the sound, that's a different matter, I prefer to leave that to personal choice.

Cheers,
DVV

bubba966 · « **Reply #126 on:** 16 Mar 2003, 08:13 pm »

Quote from: gonefishin

Randy...yea, they do have an isolated ground...good thing to keep in mind!

Not all Hospital grade outlets have an Isolated ground. This Leviton outlet is a good example. http://cgi.audiogon.com/cgi-bin/cl.pl?accspowr&1052943309&2&3&4&.

Quote from: gonefishin

I'm surprised I haven't heard of anyone trying the outlets with the orange triangle

http://www.currentsource.com/Marinco%20Isolated%20Ground%20Devices.htm

thanks fer the reply>>>>>>>

The orange triangle is to certify that it's an Isolated Ground device.

So an IG8300 outlet would have both the green dot, as well as the orange triangle as it's a 20A Hospital Grade Isolated Ground recptacle.

I've used both 20A Industrial Grade (5352-W) and 20A Hospital Grade (IG8300) outlets. While the 5352-W's did grip the plug fairly well, it wasn't quite as tight as the IG8300's.

So you are getting a better connection with a Hospital Grade receptacle, even on standard 15A plugs.

An IG8300 outlet usually costs around $10, while a 5352 outlet is usually around $5. I don't the the extra $5 for an IG8300 to be excessive as I feel that the better connection is worth the $5.

Dan Banquer · « **Reply #127 on:** 16 Mar 2003, 09:45 pm »

If the magnet wire on the voice coil of the tweeter is a small as you say it is, do you think that nullifies arguements about skin effect in loudspeaker cable? or not?
As far as stranded wire is concerned; my guess is that it would depend on how you wind it, or lay it out as the case maybe. BTW, I think Mogami still makes some of the most non reactive speaker wire there is. I have heard of some folks using that in the pro side of the business.

JohnR · « **Reply #128 on:** 16 Mar 2003, 10:32 pm »

Quote

However, my experience shows that flat cables get to be flat primarily by using less copper or whatever conducting material. I'm not sayin all of them are like that, but I am saying most are like that.

I see. Well, as I said, the cable I was referring to is equivalent to 10 ga. In fact, the cross-sectional area is spec'ed at 4.8 mm^2, just slightly less than the 5.3 mm^2 of your vdH.

JohnR · « **Reply #129 on:** 16 Mar 2003, 10:46 pm »

Quote from: Dan Banquer

If the magnet wire on the voice coil of the tweeter is a small as you say it is, do you think that nullifies arguments about skin effect in loudspeaker cable? or not?

I never said anything about skin effect.

Still, whether the effective change in cross-sectional area of a wire due to skin effect is significant or not... frankly I doubt it, but I guess you would have to do a simulation complete with drivers and crossover to see what effect it has, and then argue about whether x fraction of a dB is audible or not. The DC resistance of a tweeter VC is no big secret, you can usually find it right on the spec sheet. 6 ohms is a typical value. Bear in mind that the resistance of the wire is in a different location in the circuit than the tweeter voice coil, so the fact that the magnitude of the voice coil resistance swamps the wire resistance is in and of itself not a valid argument.

Quote

As far as stranded wire is concerned; my guess is that it would depend on how you wind it, or lay it out as the case maybe.

Well, we're talking about strands that are not insulated from each other. Does that change your answer?

DVV · « **Reply #130 on:** 16 Mar 2003, 11:08 pm »

Quote from: JohnR

Quote
However, my experience shows that flat cables get to be flat primarily by using less copper or whatever conducting material. I'm not sayin all of them are like that, but I am saying most are like that.

I see. Well, as I said, the cable I was referring to is equivalent to 10 ga. In fact, the cross-sectional area is spec'ed at 4.8 mm^2, just slightly less than the 5.3 mm^2 of your vdH.

John, for what it's worth, I'd go along with 4.8 mm.sq with a clear conscience. Electrically, I would expect that cable to be capable of at least 150 amperes in peaks, which means its internal resistance has to be low enough to make it happen.

As for the sound, well, I'd have to audition it to know. As you would have to audition my vdH to know.

Cheers,
DVV

JohnR · « **Reply #131 on:** 16 Mar 2003, 11:15 pm »

Sure, the sound is one thing and... but DVV, I'm sorry, but I thought that this was a "no-nonsense" kind of cable discussion. What is the "internal" resistance? Is that different from what would be measured if one put a suitable ohm-meter on either end of the cable?

JohnR

Dan Banquer · « **Reply #132 on:** 17 Mar 2003, 02:08 am »

As far as the voice coil being in a different part of the cicuit that is without question. That relates more to the issue of damping factor. What I am getting at here is that if the higher frequency energy coming down the speaker cable winds up in the voice coil of the tweeter. If you think about it for a minute it does seem a liitle absurd. ( 12 AWG to 24 AWG?) As far as weather the strands are insulated from each other or not is the difference (in this application) between litz wire and "regular" wire. Personally I see no need for litz wire in this application. Where are you going with this John R.?

gonefishin · « **Reply #133 on:** 17 Mar 2003, 02:55 am »

Hi bubba...as far as the outlet goes...the only thing you gain by going with hospital grade is a better and tighter connection...which can be found in many industrial grades. You see people sell these things to audiophiles saying..."green dot/hospital grade"...other than getting a good connection...which can be had elsewhere...why are outlets that were to be designed for safety in an oxygen rich environment so special to audiophiles? If it is only the quality of the connection...than they can easily do without the green dot.

I suppose your right tho...for how close they are in price...why not.

thx fer the comments

Randy...not sure what I'll end up doing to the sacd1000. I've got to finish some other projects first...maybe I'll end up doing something to it next year. I must admit...I am kinda worried about voiding the warranty...even tho I haven't had any problems so far *knock...knock* (on wood)

any suggestions?

JohnR · « **Reply #134 on:** 17 Mar 2003, 05:33 am »

Hi Dan, I'm not going anywhere with it, I was querying your statement that a stranded wire has lower impedance in the audio band than a solid wire of the same cross-sectional area (CSA).

At least, that was what you appeared to be saying.

Concerning a Litz type of construction or multiple insulated strands, if the remnants of EM theory left in my brain mean anything, this reduces the inductance compared to a solid wire of the same CSA. This is why you see power lines with four or more smaller wires, rather than a single large one. Yes 60 Hz is low but these wires run for hundreds of miles.

Also, a flat wire has lower self-inductance than a circular one of the same CSA.

Whether the difference in inductance is significant -- honestly I have no idea. I make up some cables, and they seem to sound better than the ones I had before, that's good enough for me

DVV · « **Reply #135 on:** 17 Mar 2003, 06:04 am »

Quote from: JohnR

Sure, the sound is one thing and... but DVV, I'm sorry, but I thought that this was a "no-nonsense" kind of cable discussion. What is the "internal" resistance? Is that different from what would be measured if one put a suitable ohm-meter on either end of the cable?

JohnR

No, that's the resistence of the cable itself, as measured by a milliohm metre. Over here in Europe, everybody calls it "internal resistence". This is the cable's own resistence, which is in series with the amp and therefore adds up with the amp's own output impedance to mess up our damping factor.

Sorry for the semantic foul up.

Cheers,
DVV

randytsuch · « **Reply #136 on:** 17 Mar 2003, 06:45 am »

Gonefishin,
One of these days, I was going to post on the mods I have done to my SACD 1000, but Stan Warren modded it before I started messing with it.

Randy

JohnR · « **Reply #137 on:** 17 Mar 2003, 09:22 am »

Ah, DVV, gotcha. Thanks

Dan Banquer · « **Reply #138 on:** 17 Mar 2003, 11:14 am »

John R: If the electric company uses litz wire for long runs, than I would hazard a guess that it's due to the high voltage. (24Kv or higher)