• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Townsend Isolda cable

Status
Not open for further replies.

solderdude

Major Contributor
Joined
Jul 21, 2018
Messages
7,054
Likes
13,681
Location
The Neverlands
We don't need the reference as we now have a graph showing voltages. Input voltage 55.5mV, and 1.1mV cable loss @ 10kHz. What's the formula that gives 23dB cable loss using these input parameters?

(There might be some error margin on the 55.5mV input voltage, but that error would need to be really huge to get a 23dB cable loss).
There is no reference as the 2i2 input pot can be in any position. Also the 55.5mV is not accurate.

Let's say the 55.5mV is correct. Then at 200Hz the impedance of the load = 8 Ohm.
55.5mV over 8 Ohm = 6.9mA. Do note this is the total signal containing the entire frequency band.

at 200Hz the used cable has a voltage drop of 90uV (the small 10uV bump is mains hum)
90uV / 6.9mA = 13mOhm and given the fact that his cable is 8.4 mOhms per meter (so the measured side 4.2Ohm/meter) would mean the cable is 3meter long.
The article states 7m long so something is fishy and the reference is not correct, the 7m is not correct, the Ohm/meter is incorrect, the load is incorrect.
Acc to mr. Townshend the 7m Isolda is 2.45uH, 65.8nF, 189mohm (= 13.5 Ohm/meter for 1 conductor and not the 4.2 Ohm per meter).

Apples and pears, no reference.

To really be able to tell something you need the sweep also with 2i2 of the input signal. Certainly because the RMS value is measured over the entire frequency range (a total, well not total as >500Hz it doesn't register correctly) and the 90uV value is (most likely) not calibrated and is only part of the entire 'energy'.

You really cannot use the data as there is no actual reference.
 
Last edited:

solderdude

Major Contributor
Joined
Jul 21, 2018
Messages
7,054
Likes
13,681
Location
The Neverlands
Indeed so the 55.5mV is no reference in this case.
mr Townshend should have made a plot of the input signal as well. For more than 1 reason as we have no idea if the 2i2 voltage is actually correct as well.
The calculations above from the uV in the plots are meant to show you can't compare apples and pears.
 

SIY

Major Contributor
Technical Expert
Joined
Apr 6, 2018
Messages
5,314
Likes
10,904
Location
Phoenix, AZ
And the big ol’ loop.
 

Cbdb2

Active Member
Joined
Sep 8, 2019
Messages
243
Likes
156
Location
Vancouver
All hes found is a way to exagerate the miniscule differences in level at 20khz but dosnt understand how.Then imagines something else is going on even thou theres zero proof ( blind testing) and zero physics to back him, so always back to the wrong idea that characteristic impedance matters in audio.
 

Cbdb2

Active Member
Joined
Sep 8, 2019
Messages
243
Likes
156
Location
Vancouver
I have measured the voltages in these two images. Input 55.5 mV and set the y axis to volts. Driven from the monitor speaker output of the 2i2 set to maximum. View attachment 95762 View attachment 95763 View attachment 95763
What happened to ohms law? That should NOT be a flat line. Its the current thru the speaker times the impedance of the wire. The current follows the impedance curve of the speaker which is not flat. If asked this before and even posted sims to show the effect. No answer.
 

Cbdb2

Active Member
Joined
Sep 8, 2019
Messages
243
Likes
156
Location
Vancouver
And, by the way these kind of straw clutching measurements, across a wire have been done before and have been posted on diyaudio's website. Same response.
 

Speedskater

Addicted to Fun and Learning
Joined
Mar 5, 2016
Messages
723
Likes
484
Location
Cleveland, Ohio USA
I'm not at all sure that he measured the Resistance, Capacitance & Inductance of the cables that he actually used. I think that some of the info was derived from generic charts & graphs and other from mechanical measurements.
 

Cbdb2

Active Member
Joined
Sep 8, 2019
Messages
243
Likes
156
Location
Vancouver
What came first, the cable or the test. Was the cable designed to fix a problem discovered while testing cables or was the test designed to show an improvement in this one cable? I think we all know which. And the test fails.

What exactly is this cable trying to fix?
 

Cbdb2

Active Member
Joined
Sep 8, 2019
Messages
243
Likes
156
Location
Vancouver
I'm not at all sure that he measured the Resistance, Capacitance & Inductance of the cables that he actually used. I think that some of the info was derived from generic charts & graphs and other from mechanical measurements.
Was that a reply to me? No measurements neccesary.
 

ahofer

Addicted to Fun and Learning
Forum Donor
Joined
Jun 3, 2019
Messages
899
Likes
1,428
Location
New York City
You actualy believe that guy? Your further gone than I thought. How can we have a technical discusion when one of the participants believes in magic and thinks his cable has it.
Well, you probably aren’t generating enough alpha brain waves to understand.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
30,219
Likes
88,625
Location
Seattle Area

Cbdb2

Active Member
Joined
Sep 8, 2019
Messages
243
Likes
156
Location
Vancouver
Your measurements will show similar results. Its not the measurement its the conclusions that are wrong. The signal across the speaker is all that matters and this was never measured becuase it dosnt sell snake oil, it proves theres no audible difference.
 
Status
Not open for further replies.
Top Bottom