Townsend Isolda cable

[March Audio]

http://www.ee.ic.ac.uk/hp/staff/dmb/courses/ccts1/01700_LinesA.pdf

 

[SIY]

http://www.ee.ic.ac.uk/hp/staff/dmb/courses/ccts1/01700_LinesA.pdf

View attachment 24148

But... but... but... HE DID A VIDEO!!!! PROOF!!!!!

 

[March Audio]

But... but... but... HE DID A VIDEO!!!! PROOF!!!!!

Why is there a propensity for HiFi industry to think domestic audio operates in a fundamentally different and contrary fashion to proven physics and electrical/electronic theory?

Is it because there is always a ........I was going to say gullible audiophile ready to lap it up, but thats not fair. Why should they know anything about this level of technical detail? They have no chance of weeding out the BS.

 

[SIY]

There's a reason why I never ask for cables and foo accessories for review. The peddling of this stuff is distasteful, and I have little patience for transparent hucksters.

 

[solderdude]

His squarewave shots do show a (regardless of origin) HF roll-off at around 200kHz (5us risetime) while his cable does not.
So there seem to be measurable differences between a generic cable and his cable.
The claim is A: this is due short length characteristic impedance and B: that this is very audible.

I won't get in the characteristic imp. debate (which is Max's point) but do have a problem with the audibility claim of about -6dB at 200kHz which isn't affected by phase shifts in this case given the Isolda seems to conduct the squarewave more truthfully.
The video suggests that there is a different 'roll-off' in the treble (combined with resistance differences).
I don't feel Max's test is well executed nor documented.

On purpose to huckster or other reason.

It would be quite easy to measure this 'effect' using an RME ADI2 for instance and using noise, music or other signals measuring up to almost 200kHz.
Then it can be seen what part is resistive and what part is not and how that would affect the audible range.

 

[March Audio]

I didnt look in detail at anything beyond the original video because the claims contradict long established and proven electrical principles. I sort of lose interest at that point because you know something is wrong, test set up, execution or whatever.

 

[Max Townshend]

Which extend beyond audio frequency by definition. The infinite odd harmonics are what make it a square wave.

• In a circuit with a “short” line, the terminating (load) impedance dominates circuit behavior. The source effectively sees nothing but the load’s impedance, barring any resistive losses in the transmission line.
• In a circuit with a “long” line, the line’s own characteristic impedance dominates circuit behavior.

I thought Max was nulling (the scope is) and listened to nulls, but he isn't listening to a nulled signal but measures the voltage drop across 7m of cable. (my bad didn't look at the schematic)
Seeing a few snags there.

Would like to see spectral differences from 10Hz to say 100kHz between the different cables and should include the differences in DC resistance between the cables.
That would be much more revealing than the video.
This would be extremely easy to do and can show differences well beyond audibility.
You can even factor in Ohmic losses once these are known.

http://www.ee.ic.ac.uk/hp/staff/dmb/courses/ccts1/01700_LinesA.pdf

View attachment 24148

View attachment 24147

When I went to school, transmission line behaviour started at DC. Note, Zc is sqrt L/C. There is no frequency component.
You have highlighted < 20kHz, so how do you explain the pink noise change in the video?

 

[SIY]

You have highlighted < 20kHz, so how do you explain the pink noise change in the video?

The same way I explain videos of magicians disappearing coins.

Although ethical magicians admit that their aim is to fool people, which distinguishes them from cable-peddlers.

 

[Max Townshend]

His squarewave shots do show a (regardless of origin) HF roll-off at around 200kHz (5us risetime) while his cable does not.
So there seem to be measurable differences between a generic cable and his cable.
The claim is A: this is due short length characteristic impedance and B: that this is very audible.

I won't get in the characteristic imp. debate (which is Max's point) but do have a problem with the audibility claim of about -6dB at 200kHz which isn't affected by phase shifts in this case given the Isolda seems to conduct the squarewave more truthfully.
The video suggests that there is a different 'roll-off' in the treble (combined with resistance differences).
I don't feel Max's test is well executed nor documented.

On purpose to huckster or other reason.

It would be quite easy to measure this 'effect' using an RME ADI2 for instance and using noise, music or other signals measuring up to almost 200kHz.
Then it can be seen what part is resistive and what part is not and how that would affect the audible range.

In the video, the change in level between the two cables on pink noise is between 6dB and 12dB, below 20kHz.
The test I do is quite simple and you are all free to replicate it. The easiest way to get an 8 ohm cable is to parallel 6 x 50 ohm coax. It works very well.

 

[Max Townshend]

The same way I explain videos of magicians disappearing coins.

Although ethical magicians admit that their aim is to fool people, which distinguishes them from cable-peddlers.

I suppose you still believe the world is flat.

 

[RayDunzl]

I like the name.

"I sold a" cable.

 

[PierreV]

It's interesting to note that there are tons of areas where conductivity, signal integrity, interferences are critical, that those areas have seen mind-boggling improvements over the last three or so decades and that, curiously none of these improvements relied on the strategies used by speaker cables vendors.

On top of that, no fancy speaker cable design seems to have demonstrated clear improvements that would have pushed that industry towards some common minimal set of design parameters. Even if there is "another science" running in parallel to the standard one, one could expect "researchers" to converge to some basics.

Finally, fancy speaker cable vendors seem to be regularly upgrading their cables and refreshing their product lines... somehow, the new cable is always audibly better than the one it replaces which itself was... ad nauseam.

 

[SIY]

 

[Max Townshend]

Why is there a propensity for HiFi industry to think domestic audio operates in a fundamentally different and contrary fashion to proven physics and electrical/electronic theory?

Is it because there is always a ........I was going to say gullible audiophile ready to lap it up, but thats not fair. Why should they know anything about this level of technical detail? They have no chance of weeding out the BS.

I like the name.

"I sold a" cable.

"Isolda" comes from our play on Arthurian legends (tristan and isolde). We have The Rock turntable, the Excalibur Arm, The Glastonbury speakers
the Merlin power supply and the Grail pick up cartridge. Isolda comes from when we made 8.2 ohm cable from 6 x RGW787 (equivalent) 50 ohm cable in the early 80s. There were many conductors to solder together, hence the play-on-words I solder and I solder.

 

[solderdude]

"Isolda" comes from our play on Arthurian legends (tristan and isolde).

Ray's explanation is more fun.

In the video, the change in level between the two cables on pink noise is between 6dB and 12dB, below 20kHz

Could very well be caused by the difference in resistance of the cable.
This is why I mentioned that I would like to see the spectrum of both cables (up to 100kHz at least) and would like to know the exact resistance of the wires that were tested.
When it was as severe as your test seems to show it is, then I reckon all cable tests and blind tests would already have shown this to be a serious problem.

When you can't show it in different spectra to me it does not count and can be parlor trick.
I guess I have to wait till Amir tests it.

 

[March Audio]

When I went to school, transmission line behaviour started at DC. Note, Zc is sqrt L/C. There is no frequency component.
You have highlighted < 20kHz, so how do you explain the pink noise change in the video?

I think the question is how do YOU explain it?

 

[mansr]

Maybe I am right! I have passed this by professor Jack Dinsdale, the inventor of the transformerless transistor amplifier, Geoff M, the inventor of the computer cache memory, Professor Cyril Murray, Sydney university electrical engineering and many other graduate engineers. They all agree.

I put the question to James Clerk Maxwell and Oliver Heaviside. Both just laughed.

 

[Max Townshend]

It's interesting to note that there are tons of areas where conductivity, signal integrity, interferences are critical, that those areas have seen mind-boggling improvements over the last three or so decades and that, curiously none of these improvements relied on the strategies used by speaker cables vendors.

On top of that, no fancy speaker cable design seems to have demonstrated clear improvements that would have pushed that industry towards some common minimal set of design parameters. Even if there is "another science" running in parallel to the standard one, one could expect "researchers" to converge to some basics.

Finally, fancy speaker cable vendors seem to be regularly upgrading their cables and refreshing their product lines... somehow, the new cable is always audibly better than the one it replaces which itself was... ad nauseam.

Please don't get us confused with 99% of the high end cable makers where they change the model regularly and they have a range of "Best" cables. We have not changed the basic design of our Isolda cable in 30 years, because if it was right then, it is still right now. Goertz are the only other maker of this cable. It all started in the late 70s in Japan when the plaited impedance matched cable was introduced. It was marketed by Polk (Cobera) and Monitor Audio. Unfortunately for Monitor Audio, this cable smoked the Naim 250 because Julian Vereker deliberately omitted the 3uH choke on the output, that would have made his amplifier stable with 10nF. Naim did this to force customers to purchase at least 3.5m of their highly inductive/low capacitance, Zc about 300 ohms. Naim were so powerful then that they blamed the Monitor Audio cable and not their amplifier design. They forced Monitor Audio and Polk Cobera out of the market.
We include the 3.5 uH in our standard speaker cables to allow for this.

 

[March Audio]

In the video, the change in level between the two cables on pink noise is between 6dB and 12dB, below 20kHz.
The test I do is quite simple and you are all free to replicate it. The easiest way to get an 8 ohm cable is to parallel 6 x 50 ohm coax. It works very well.

I havent watched the video. Dont you think a change in signal level of 12dB would be hugely subjectively noticeable? Yet you can change cables and find differences often indistinguishable.

 

[Max Townshend]

I think the question is how do YOU explain it?

View attachment 24154

I havent watched the video. Dont you think a change in signal level of 12dB would be hugely subjectively noticeable? Yet you can change cables and find differences often indistinguishable.

The cables you are changing have only minor differences and yes, it is hard to distinguish between them, But there is a big difference between 80 ohm+ cables and 8 ohm cables. Watch the video. You might find out what I am talking about.