Hi keantoken,
-Chris
That's entirely possible.
Nope. To maintain equal quality, the transformers are the same and so are the speakers. The transformers that you typically find in a 70V speaker are much smaller than the one at the source, and for "Hi-Fi" they would be the same size at each end. I'm not a fan of transformers for audio, so the solution might be amplifiers at the speaker end. Digital audio being the way you transmit that audio information. It's ugly no matter which way you look at the problem if you are talking very high quality audio. For background music the transformers are the most direct and cheapest solution I can think of.
-Chris
Cnris,
I agree for any reasonable wire length you probably couldn't hear the difference even with the cheapest zip cord as long as it wasn't way to small a gauge.
For a distributed speaker system with many speakers on the same mono line connection as you'd see in a store of other commercial application a transformer at each speaker is probably the simplest solution with a matching transformer at the power amps. You could be talking about hundreds of feet of wire so it seem the most practical solution. If you went with the digital solution then you would not only need and amplifier at each speaker but power to drive those, that would seem to just complicate the situation.
I agree for any reasonable wire length you probably couldn't hear the difference even with the cheapest zip cord as long as it wasn't way to small a gauge.
For a distributed speaker system with many speakers on the same mono line connection as you'd see in a store of other commercial application a transformer at each speaker is probably the simplest solution with a matching transformer at the power amps. You could be talking about hundreds of feet of wire so it seem the most practical solution. If you went with the digital solution then you would not only need and amplifier at each speaker but power to drive those, that would seem to just complicate the situation.
If you want to find cable which doesn't change the sound, you need to conduct DBLTs on them ... like I have.
Absolute Listening Tests-Further Progress - Fryer & Lee
To cut a long story short, the best speaker cable is Lightning Conductor
The worst were the braided Golden Pinnae stuff.
This was in the late 70's but I see no reason for results to be any different this Millenium.
And NO. This is NOT my usual tongue-in-cheek stuff.
The only possible criticism of Lightning Conductor is its poor WAF
And you thought DBLTs only came up with null results
Various caveats about choice of amp & speaker in that paper IIRC ...
WAF : wife acceptance factor
Absolute Listening Tests-Further Progress - Fryer & Lee
To cut a long story short, the best speaker cable is Lightning Conductor
The worst were the braided Golden Pinnae stuff.
This was in the late 70's but I see no reason for results to be any different this Millenium.
And NO. This is NOT my usual tongue-in-cheek stuff.
The only possible criticism of Lightning Conductor is its poor WAF
And you thought DBLTs only came up with null results
Various caveats about choice of amp & speaker in that paper IIRC ...
WAF : wife acceptance factor
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Hi kgrlee,
The WAF is real easy. They do not want to see any wires. It's just worse with wire that you notice no matter the size.
As for a listening test, I'm pretty sure that a lot depends on the amp and load as to how sensitive they might be about the loading. Did you get a chance to study the termination, or were they just wrapped around the speaker terminals at each end. Some terminations are much better than others, and the termination effects (hopefully) will make the greatest difference.
My own testing in the 80s really only showed wire that had a problem. The good ones were all indistinguishable from each other. Probably because they didn't upset the amplifier. In that case the speaker loads were quite easy on the amplifiers. We tried a number of amplifiers to find one that might show differences between the good wires as the one guy pushing his super duper wire couldn't hack that they all sounded the same. I think that once you get above a certain point in a system with speaker wire, any other differences are too slight to reliably pick out.
Those were strange days in the early 80s. Good audio was dying and junk was on the upswing.
-Chris
The WAF is real easy. They do not want to see any wires. It's just worse with wire that you notice no matter the size.
As for a listening test, I'm pretty sure that a lot depends on the amp and load as to how sensitive they might be about the loading. Did you get a chance to study the termination, or were they just wrapped around the speaker terminals at each end. Some terminations are much better than others, and the termination effects (hopefully) will make the greatest difference.
My own testing in the 80s really only showed wire that had a problem. The good ones were all indistinguishable from each other. Probably because they didn't upset the amplifier. In that case the speaker loads were quite easy on the amplifiers. We tried a number of amplifiers to find one that might show differences between the good wires as the one guy pushing his super duper wire couldn't hack that they all sounded the same. I think that once you get above a certain point in a system with speaker wire, any other differences are too slight to reliably pick out.
Those were strange days in the early 80s. Good audio was dying and junk was on the upswing.
-Chris
Output Coils
I didn't mean to push the thread off of amplifiers onto speaker cable by my responses to some of the posts that touched on speaker cable issues.
My bad.
Anyway, I'd like to continue the discussion on compact output coils a bit more.
We've touched pretty well on magnet wire, coil mechanical stabilization and crosstalk. I think we mostly agree that no more than 2uH is necessary in properly designed amplifiers, and less is desirable if possible.
There seems to be complete agreement that the coils should be doped or mechanically stabilized in some other way.
I do believe at this point that compact coils have an advantage in regard to crosstalk and electromagnetic footprint, but they may sometimes have higher resistance. This is a tradeoff.
It is yet unclear how much resistance is considered small enough and why. Will 20 mohm or 30 mohm make an audible difference? Is it worth it to push it down further into the low teens or single digits?
There seems to be the usual inclination to go to large AWG, but it would be nice to see the reason articulated if it is more than just getting the dc resistance down.
Is skin effect any consideration at all? Should we be concerned that the effective resistance will change within the audio band for large-AWG wire, even though the larger periphery will usually make its total dc + ac resistance smaller than a smaller AWG? To what extent does skin effect de-value going to a larger AWG if dc resistance is low enough in any case?
Are there particular disadvantages to smaller-AWG as long as the resistance target is met? For example, are there current density issues that come into play in a bad way when smaller AWG is used even if there is no resistance or dissipation issue?
Note that I am playing engineering tradeoff Devil's Advocate here. I am definitely not concerned with the cost of the copper here.
Cheers,
Bob
I didn't mean to push the thread off of amplifiers onto speaker cable by my responses to some of the posts that touched on speaker cable issues.
My bad
.Anyway, I'd like to continue the discussion on compact output coils a bit more.
We've touched pretty well on magnet wire, coil mechanical stabilization and crosstalk. I think we mostly agree that no more than 2uH is necessary in properly designed amplifiers, and less is desirable if possible.
There seems to be complete agreement that the coils should be doped or mechanically stabilized in some other way.
I do believe at this point that compact coils have an advantage in regard to crosstalk and electromagnetic footprint, but they may sometimes have higher resistance. This is a tradeoff.
It is yet unclear how much resistance is considered small enough and why. Will 20 mohm or 30 mohm make an audible difference? Is it worth it to push it down further into the low teens or single digits?
There seems to be the usual inclination to go to large AWG, but it would be nice to see the reason articulated if it is more than just getting the dc resistance down.
Is skin effect any consideration at all? Should we be concerned that the effective resistance will change within the audio band for large-AWG wire, even though the larger periphery will usually make its total dc + ac resistance smaller than a smaller AWG? To what extent does skin effect de-value going to a larger AWG if dc resistance is low enough in any case?
Are there particular disadvantages to smaller-AWG as long as the resistance target is met? For example, are there current density issues that come into play in a bad way when smaller AWG is used even if there is no resistance or dissipation issue?
Note that I am playing engineering tradeoff Devil's Advocate here. I am definitely not concerned with the cost of the copper here.
Cheers,
Bob
Not to drag this out any longer, but which of these most closely resembles "lightning conductor"?
Lightning Conductors and Copper Cables - Series 100- Lightning Rod Parts
Hi AJT,
Easily done. Just try and use them at home!
-Chris
i saw him use that on him 845 SET....
Hi Bob,
When talking about output chokes, they do relate to speaker wire as they are in series. Then there are the speaker crossovers to deal with. In comparison, that little choke doesn't seem to be a massive problem. The issue has to be kept in perspective at the end of the day. However, let's continue investigating as we may find out something unexpected.
Sorry Bob, it's late and I'm a little punchy.
-Chris
When talking about output chokes, they do relate to speaker wire as they are in series. Then there are the speaker crossovers to deal with. In comparison, that little choke doesn't seem to be a massive problem. The issue has to be kept in perspective at the end of the day. However, let's continue investigating as we may find out something unexpected.
Yes. At least you can't saturate an air coil.
Yes, and that is how we got off-track. This question is tied to contact resistance and wire resistance as well as skin effect. I don't know how you would come to an answer without considering these other things.
Self support and good heat conduction if it's an issue. Then there is the entire resistance question as you have pointed out.
Again we have to compare this effect to the rest of the circuit. Speaker wire and crossovers.
Resistance and dissipation are tied to wire size. Current density will give rise to temperature increases, so you can't talk about one thing in isolation I don't think. Not unless you want to hit the market with "Cryo-coils" that come with Dewar full of liquid nitrogen. It would probably become a high-end fad. I wonder, would "Cryo-Cable" shatter if it's stepped on?
Sorry Bob, it's late and I'm a little punchy.
-Chris
Keantoken,
I'm not sure what kgrlee is referring to with lighting cable but in the radomes that I have worked on we used a flat braided copper about 1/2" wide and fairly thin and flat that we bonded onto the radome. There were multiple braids that would go to a center point like a star ground and that would be tied to the fuselage of whatever plane they were mounted on.
I'm not sure what kgrlee is referring to with lighting cable but in the radomes that I have worked on we used a flat braided copper about 1/2" wide and fairly thin and flat that we bonded onto the radome. There were multiple braids that would go to a center point like a star ground and that would be tied to the fuselage of whatever plane they were mounted on.
Traditional 1970s British Lightning Conductor (what we tested) was a solid Cu busbar 3/4" x 1/8" thick.
We insulated it with Sellotape. I've no idea whether different configurations with same Cu section, insulation etc would have made an audible difference as we've not tested them.
The best of the rest was the thickest of the OFC Monster Cables. The difference (both audible & measured) between LC & 2nd best was a slight droop in HF response.
I was humbled to find some of our Listening Panel could reliably detect frequency response changes of the order of 0.1dB under certain circumstances.
I'd rather the AES paper stand as a simple way to test if cables changed the sound. And YES! Cables change the sound but not in the way da deaf Golden Pinnae claim.
____________________
Back to Inductors
My thoughts on this are summarized in #6844. To answer Bob's latest post ..
20 - 30 mOhm is plenty small enough .. even if you use Lightning Conductor cables.
I think crosstalk and picking up EVIL Class B currents are well avoided by those versed-in-the-art of good layout. The number of people versed-in-the-art is still very small but I think increasing.
All this is suggests the inductors on most (?) competent DIY amps and commercial designs are OK.
The one factor that hasn't been tested is the effect of wobbly turns. Even the theoretical pontification on this has been airy fairy at best.
Anyone going to do some 'real life' tests on a 1ppm THD20k amp to see if this is just another Golden Pinnae red herring?
As I said, it is easy enough to dip a close wound coil in epoxy but that's another pain in production.
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Toroids should be superior in this, and equal or better in other metrics, problem solved I think.
I have test wound a few and plan to use them in the next amp, have you considered them?
Best wishes
David
/OT
>Toroids should be superior
Nevertheless, I still prefer this one?
Cheers, E.
PS: Normally, this coil finds its application in a slightly different field.
>Toroids should be superior
Nevertheless, I still prefer this one?
Cheers, E.
PS: Normally, this coil finds its application in a slightly different field.
Hi EdmondNevertheless, I still prefer this one?
Doesn't the one in the Halcro look a bit like that?
It's nicely sculptural, but air core toroids are too.
And I plan to counter-wind a second helix to cancel the poloidal fields.
Should look "hi-tech sculpture" and it really has a function, not just phoney pseudo tech.
Haven't actually optimised it yet, I suspect it's very broad optimum so I haven't searched much or done maths.
You (or anyone) seen any data on best toroid proportions?
Best wishes
David