Archived from groups: rec.audio.pro (
More info?)
"dufus" <seanbroderick20003@yahoo.com> wrote in message
news:9da972e8.0411200442.1437f1cc@posting.google.com
>
http
/www.borbelyaudio.com/kit_upgrades_term.asp
>
> Is this total hooey, or what?
Total hooey.
I presume that Borbley didn't get the standard EE lecture about transmission
lines that starts out by saying that a cable has to be some fraction
(usually at least 1/8 probably far more) of a wavelength at the highest
frequency of interest, to be thought of as a transmission line.
That's a little more than a mile at 20 KHz.
If we lift our sights to SACD-like 100 KHz, we're still talking over 1,000
feet before a cable could in our wildest imaginings be thought of as a
transmission line.
>I thought at audio frequencies these effects are very small, and
>completely imperceptible.
This would be orthodox thinking. However, in a sighted evaluation I might be
cable to convince you that you were hearing something.
> The longest mic cable I ever use is 100 ft.
My longest snake is 150 feet and I regularly plug 20-50 feet of mic cable
into it. That's a room that is about 80 feet deep. In a big room this could
double.
>But no mic will happily drive 150 ohms.
Depends what you call happy.
> For line levels, the lower Z that any output stage must drive with
> this approach definitely has distortion and voltage swing drawbacks,
> versus the 10k input Z of a bridging input.
There are some pretty robust line drive output stages out there. Many will
drive their building-out resistors (i.e., an external short circuit) to +4
without clipping. They wont' do +22 cleanly, of course. Nonlinear
distortion will rise but still remain way below 0.05%.
> What do y'all think?
Borbly has spent too much time reading the pseudoscience in some of the
ragazines that publish his construction projects. He seems to believe
everything they say.