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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 9th Jun 2018, 11:00 am   #121
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Default Re: Speaker Cable of Yesteryear

Let's try another analogy for transmission lines.

A pipe can work as a waveguide for sound.
If I stick my head over the edge of a deep well and shout. I'll hear an echo back from the water below. The sound wave from my gob propagates downwards in a transmission line of some acoustic impedance. Smacking into the surface of the water comes as a sudden and large mismatch. Some sound goes down through the water, a lot reflects and propagates upwards back to me. All easily done in real life. Less obviously, the mouth of the well is another change in acoustic impedance and some of the echo leaves the well, but some goes back down again. You don't need a short circuit to reflect waves, an open circuit does it too. Small changes in impedance create small reflections... think of a change in diameter in the well shaft. It's easy to visualise a reflection from the ledge formed by it necking down, but you can also get a reflection from an opening-out.

Where there are multiple mismatch locations you can get a right mess of echoes bouncing to and fro and you get badly muffled sound. Waves that have been there and back and there again combine with those on the first trip and some frequencies get boosted some get cut and you have the sound effect of 'listening down a pipe'

All the same things happen electrically, but as electrical signals move near the speed of light, not near the speed of sound, the lengths or frequencies needed to play these tricks ar vastly larger.

The pseudoscience used to sell audiophile wire treats the signals as if they were speed of sound and mechanical. These people have no understanding of the speed of electrical waves and they have no sense of scale in terms of what amplitudes and frequencies are audible.

They don't know what they're missing

That bit of Woolies bell wire moves electrical signals at 60% of the absolute speed limit of our universe. Even Jeremy Clarkson would be impressed.

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Old 9th Jun 2018, 11:00 am   #122
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Default Re: Speaker Cable of Yesteryear

Thanks for piquing my interest in signal cables David! I'm having a lovely time googling all about the problems and arguments about long signal cables that were being raised by the mid 1800's. Apparently Thomson's telegraph experiments came out of research done initially by our old friend Michael Faraday.
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Old 9th Jun 2018, 12:53 pm   #123
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Default Re: Speaker Cable of Yesteryear

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A young guy, William Thomson was there and he was of a more mathematical bent. He was a genuine smart cookie, but was then young and in a junior position. He wasn't the first to have worked out the maths of transmission lines, but he deduced that the line was of the wrong impedance for what was driving and loading it. The big names of the day weren't listening. They got the voltage wound up to beyond the capabilities of the undersea cable's insulation and they burned the thing out. What was happening was that different frequency components of the Morse signal were getting different delays and there were echoes, and the signal was getting garbled by the line.

Bit of an expensive mistake!

William Thomson invented lots of things, did lots of good science and was an all-round good guy. He's remembered as Lord Kelvin.
David
While I normally regard Lord Kelvin with a reasonable amount of respect, he managed to write off x-rays & radio when they became known, & reckoned heavier than air flight was impossible.
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Old 9th Jun 2018, 4:49 pm   #124
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Default Re: Speaker Cable of Yesteryear

Well I ended up using Masterplug Speaker Cable which arrived this morning in the post.
It is discontinued, but very good quality. It is a flat cable 16 gauge, and the copper has a nice ROSE pink tint quality to it. Different to the bright shiny copper you get with other cables . . . .

Sounds as you would expect . . . . Good cable all round . . . .
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Old 10th Jun 2018, 12:16 am   #125
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Default Re: Speaker Cable of Yesteryear

I have some bell wire arriving next week. Going to give that a try also.
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Old 10th Jun 2018, 9:23 am   #126
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Default Re: Speaker Cable of Yesteryear

Seven posts relating to horn speakers moved to a new thread here:-

https://www.vintage-radio.net/forum/...d.php?t=147294
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Old 10th Jun 2018, 11:26 am   #127
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Default Re: Speaker Cable of Yesteryear

Post number 7 in the moved thread is mostly about tapered loudspeaker cables, but in view of the dimensions involved it's only of comedic value.

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Old 11th Jun 2018, 4:06 pm   #128
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Default Re: Speaker Cable of Yesteryear

Hi. I got some Philips 20 gauge speaker cable to play with. It is pretty much bell wire dimensions, and I can't hear any difference through my speakers. So you don't really need thick special wires to wire up your HiFi in most domestic set ups. This has been a real learning curve for me, and a fun experiment.
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Old 11th Jun 2018, 7:35 pm   #129
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Yes, it comes as quite a surprise to people these days. There are so many aficionados telling each other that they need cables that will start their car or tow a ship, made out of rare and esoteric metals mounted on exotic wooden stands to hold them off the floor, and that you must spend around 14% of the cost of the rest of your setup on cables....

And the whole lot is now exposed as a house of cards (or a large pile of cr*p, however you wish to phrase it) It trades on a basic human gullibility. Once you've wasted a stupid amount of money, you become reluctant to admit it, you take action to cover it up, and you try to convince others to do the same thing so you don't feel so lonely. We've all fallen for it one way or another.

Welcome to the land of the rational!

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Old 11th Jun 2018, 8:04 pm   #130
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Hi David.

I have to admit I have falling for it from HiFi salesman in the past. I think the real reason for the lower the awg for speaker cables the better, is that the thicker the copper cable the more expensive it is. So the only benefit is more money in the salesman pocket ! It only cost me fiver for 25m of this Philips 20 gauge speaker wire from eBay, and it is perfect. Much easier to hide. Glad I finally got some sense. The only thing I have noticed unusually with this cable is the mix of standard copper strands, and tinned copper strands together. I have never come across that before.
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Old 11th Jun 2018, 8:19 pm   #131
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The only thing I have noticed unusually with this cable is the mix of standard copper strands, and tinned copper strands together. I have never come across that before.
Does it indicate polarity? Useful for ensuring the correct phasing of the speakers in a stereo system.
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Old 11th Jun 2018, 8:36 pm   #132
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Default Re: Speaker Cable of Yesteryear

Their art of seduction is highly polished. It draws a lot of people in, and once drawn in those people reinforce the belief-system with each other. It really is terribly hard to resist, and even harder to walk away from once it's got a hold on you.

Some things DO make a difference in hifi. But there is a natural law of diminishing returns. What the pundits claim is odd. All their little mods and tweaks, all the big budget items are all claimed to make massive life-changing differences. So where are the cases of "I couldn't really tell a difference" and "I could hear a small difference but I couldn't make my mind up which is better" and "I couldn't hear any difference" In the real world, these things should happen quite often. Their absence is deeply suspicious. They happen in all other fields, they happen in hifi when non-believers are used as test subjects.

Profiteering aside, there were some cases in the past where the usual measurements of hifi equipment missed some parameters that really did make a difference. The subjectivist brigade were right in these cases, but unfortunately it has been 'leveraged', as our American friends would put it, as a sort of proof that all measurements are aways wrong.

However, the people on the science and engineering side learned from the experience and have managed to design equipment essentially free from the imperfections involved. The people on the subjectivist side haven't noticed this, or haven't allowed themselves to notice it.

It's a case of the emperor's new clothes. Once you allow your eyes to see what is there and your ears to hear it you can watch the naked emperor and have a good laugh.

Just one thing, the people who can see the emperors new clothes don't take kindly to having reality pointed out to them. They can get quite grumpy and tend to gang up on people who disagree with them.

The subjectivists are convinced that the engineers and scientists are cloth eared
The engineers and scientists think the subjectivists are deluded.

There hasn't been a pitched battle yet.

David
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Old 11th Jun 2018, 8:51 pm   #133
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Default Re: Speaker Cable of Yesteryear

No, the polarity is marked by a white stripe down one side.
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Old 11th Jun 2018, 10:03 pm   #134
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Default Re: Speaker Cable of Yesteryear

I have heard the difference between stringy thin speaker flex (not even worthy of the term bell wire) and decent flex.

I'm dubious it's worth buying anything better (more expensive) than "three amp" flex though. Unless of course your amp is chucking out more than 72 watts RMS on a continuous sine wave for hours at a time, in which case use six amp
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Old 11th Jun 2018, 11:13 pm   #135
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Default Re: Speaker Cable of Yesteryear

Maybe 20 gauge flex will be more robust, but I am happy with this Philips cable . . . .
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Old 12th Jun 2018, 1:34 am   #136
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Default Re: Speaker Cable of Yesteryear

Getting back to the history, here in NZ in the late 1960s and into the 1970s, and quite possibly before that, it was common to use 14/0.0076 (inch) or 23/0.0076 figure-of-8 cable for connecting hi-fi amplifiers to speakers. Of the local makers of the era, AWA definitely recommended 14/0.0076. My memory tells me that Fountain recommended 23/0.0076, but I cannot confirm that. That kind of twin cable, often of a white/cream colour, was known as “Truerip” (or perhaps it was “Trurip”). There was also a “Triplerip” flat triple, double insulated, for use as power cable. The inner insulations were red, black and green, and the outer usually brown or white/cream.

It would appear that both of those twin variants were known in the UK as possible speaker cables, as Briggs included them in his cable resistance tabulation in his “Loudspeakers” book:

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Another reference is from Gordon J. King, writing as John Earl, in the 1971 book “Pickups and Loudspeakers”. Here 5 amp power cable was suggested:

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Going back to the 1930s, one may draw an interesting inference from this description of the Pye “Match-All” extension speaker link:

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For long distances between receiver and extension speaker, Pye recommended using “Match-All” transformers at both ends, in which case “ordinary twisted flex” or “bell wire” could be used without material loss. I’d guess that the “line” between the two transformers would be operating at a relatively high impedance (as compared with typical speaker impedance), maybe 500 ohms or so. But one may infer that the types of cables mentioned were seen as less suitable for direct links (without the “Match-All” transformers) at speaker impedance, probably around 2.5 ohms. So even back then, “bell wire” (however it was defined) was seen to have its limitations.

In terms of modern practice outside of specialty speaker cables, I looked at the Jaycar site, which had the following:

Bell wire: 7/0.10 mm figure-of-8

“Light-Duty Speaker Cable” 14/0.14 figure-of-8

“Heavy-Duty Speaker Cable” 24/0.20 figure-of-8

“Extra Heavy-Duty Speaker Cable” 79/0.20 figure-of-8

“Pro-Audio Speaker Cable” 2 x 18AWG double insulated


As best I can determine, the above are all standard multipurpose cable types, with speaker connection being one but not their only application.


Cheers,
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Old 12th Jun 2018, 6:30 am   #137
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Default Re: Speaker Cable of Yesteryear

In the UK, back in the day, single-insulated figure-of-eight wire was allowed for mains connections and was the usual stuff on reading lamps etc. The usual load was a 40-100W bulb. Woolworths electrical counter sold loads of the stuff. The conductors were stranded. They also sold a lighter, solid core wire with thinner PVC insulation as 'bell wire' again in figure-of-eight cross-section. These seemed to be the most popular choices for extension speakers, and later for separate stereo speakers.

They didn't then have any indication of polarity. It didn't matter for doorbells, reading lamps or mono speakers.

Later on, wiring regulations changed and mains leads were required to have an outer jacket and colour coded inner insulation. Stereo was common and the simple figure of eight stuff acquired either a ridge along one side or else one side got tinned copper strands while the other got plain copper strands so speaker phasing could be got right first time. Reading lamp flex had evolved a little to suit its new market.

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Old 13th Jun 2018, 7:02 am   #138
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Default Re: Speaker Cable of Yesteryear

From memory of my time working in "Servio Radio" south Wimbledon in the 70's we sold 2 grades of speaker cable . Both were figure-of -eight and stranded in construction with polarity indicators ether a coloured stripe down one side or a "Sharp edge". The cheaper version would fit speaker Din plugs with ease 2/3 Amp rated. The more expensive would have been 5/6 Amp rated, and would fit Jack plugs. This was very popular with the "disco boys" who were on a tight budget . We never recommended Bell wire, as it was solid in construction with no polarity indicator.
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Old 13th Jun 2018, 10:04 am   #139
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Default Re: Speaker Cable of Yesteryear

@seymour32
You're right I think - the traditional proper bell wire was solid core, not multicore. It "moulded" better to corners and skirting profiles. I remember it particularly being used with the big 4.5V batteries with knurled-screw terminals - I think they were even called "bell-batteries".

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Old 13th Jun 2018, 10:51 am   #140
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Default Re: Speaker Cable of Yesteryear

The difficulty with bell wire was in stripping the insulation without nicking the solid conductor. If you did, it was sure to break.

For front door bell pushes, you had to wind it into a spring to help it flex at the hinge side of the door.

The stranded 'reading lamp flex' was more reliable for speakers and amps that got moved for cleaning.

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