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Old 9th January 2014, 03:38 AM   #46551
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Is 'python' sorta the new 'c ' ..... ?
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Old 9th January 2014, 03:58 AM   #46552
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That is the tape recorder and it IS an RC, but I throw away the normal audio electronics and I triple the oscillator frequency.
The Mobile Fidelity tape recorders made a few years earlier used an A80Vu.
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Old 9th January 2014, 04:18 AM   #46553
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Originally Posted by john curl View Post
That is the tape recorder and it IS an RC, but I throw away the normal audio electronics and I triple the oscillator frequency.
The Mobile Fidelity tape recorders made a few years earlier used an A80Vu.
That would be 150 x 3 = 450kHz then. Wow. Divided down to 150 for erase, I guess? Did you design the new oscillator as well?
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Old 9th January 2014, 05:55 AM   #46554
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No, just a phase locked loop.
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Old 9th January 2014, 09:05 AM   #46555
Hedde is offline Hedde  Norway
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Hello. I have been following this interesting debate....and thread :-)

Can this, or part of this, be explained by the asymmetric distribution of current, making the mutual inductance complex in nature (M=Ma+jMb). Supra 2.0 probably have severe proximity issues in the audiorange beeing zip and with the conductors quite closely spaced.

Both Ma and Mb vary with frequency in no easy way changing phase and magnitude with frequency.

I am linking this old article on the topic:
http://www3.alcatel-lucent.com/bstj/...tj14-2-179.pdf
Attached the real and imaginary parts of the mutual inductance in wires in severe proximity - from the linked article. The mutual inductance is no longer in phase quadrature, but up to 10-15 degrees away from it. Could this explain the phase/delay? And must the hearability test of short t-line remove proximity from the equation?
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Old 9th January 2014, 12:30 PM   #46556
DF96 is offline DF96  England
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Originally Posted by jneutron
Do you have the article?
No.

Quote:
Originally Posted by scott wurcer
After review Bateman's plots are fatally flawed, he correctly takes the exact expression for Z0 but for some reason takes the magnitude to keep Z0 real and positive, this is just plain wrong. The equation at low frequencies yields a complex impedance and there is no problem with that. Hence his reflextion coefficients are also wrong.
Perhaps I don't need to read it, if it is so wrong.

This business of alleged significant/audible delays on audio cables always seems to come around eventually to either misinterpretation of measurements or miscalculation of theory. Bateman may have done both?
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Old 9th January 2014, 12:33 PM   #46557
DF96 is offline DF96  England
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Quote:
Originally Posted by Hedde
The mutual inductance is no longer in phase quadrature, but up to 10-15 degrees away from it.
In electronics we have a special name for the part of inductance which is not phase quadrature: we call it resistance.
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Old 9th January 2014, 12:59 PM   #46558
Hedde is offline Hedde  Norway
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In electronics we have a special name for the part of inductance which is not phase quadrature: we call it resistance.
It will lead to higher resistance, thats for sure.

Zm=jwM=-wMa+jwMb , Ma and Mb also being funktions of f.
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Old 9th January 2014, 01:51 PM   #46559
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Is 'python' sorta the new 'c ' ..... ?
It's also the language of the "rapture of the nerds" at the singularity. Python is worth it, it's free and has a huge collection of well supported libraries. Google "Hello World in 7 min." They're right. It's become my goto for quick complex calculations with nice plots.

Let me qualify what I said last night. Bateman's results might have very well been fine for his discussion of RF de-stabalization of amps but is no help in separating phase (he throws it away) from real delay. Remember at HF the line has a real positive Z0 and it does not matter. He does not really explore or need to explore the LF implications. I am in the camp that this problem will yield to lumped element analysis, but am willing to do careful experiments to look at the other viewpoint.
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Old 9th January 2014, 03:07 PM   #46560
PMA is offline PMA  Europe
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Wavelength of 20kHz wave is 15km, and some are trying to argue with delays on 2m of wire .....

It is definitely a question of HF/VHF interference reflections only and their possible influence on amplifier stability. No low frequency 'smear' here.
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Last edited by PMA; 9th January 2014 at 03:11 PM.
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