Subj : Re: 3d printing
To   : Vk3jed
From : Moondog
Date : Sat Sep 21 2019 00:43:00

  Re: Re: 3d printing
  By: Vk3jed to Moondog on Fri Sep 20 2019 08:18 pm

 > Tubes have a couple of differences to transistors in practical circuits.
 > Firstly, for moderate power levels, tube power amplifiers are often "single
 > ended", which has the second harmonic as its strongest harmonic.
 > Transistorised amps, including MOSFETs are usually configured as a
 > complementary pair, which tends to cancel out even harmonics.  Not the best 
 > musicians, who want those even harmonics.  Tube aplifiers also almost aways
 > have transformer coupled outputs, which are another source of distortion (fo
 > better or worse), due to their iron core.  Modern (hi fi) amps are generally
 > coupled to the speakers.
 > 
 >  Mo> transistors, and CMOS JFETS have been observed behaving harmonically
 >  Mo> similar to vacumm tubes.  Even among basic bulk components such as op
 >  Mo> amps there are folks who swear one vendor's version of the same chip
 >  Mo> sounds way better even though their specs are slightly different.
 > 
 > It also depends on the exact circuit design used.
 > 
 > 
 > ... Dachshund kennel ad: Get a long little doggie.
Speaking of high end audio, I remember a challenge presented by the Amazing
Randi to a maker of high end audio cables.  He challenged them by saying even i
self proclaimed and well established audiophiles would not be able to tell
the[ difference between their high end cables and a set of Monster cables he
picked up at Best Buy.  The problem was none of these "audio experts" would suc
bmit to a blind test because choosing the cheaper cable may ruin their
reputations.  I also recall Denon or a simialr company was trying to market a
proprietary cable format to compete with HDMI, and they were charging $300
for a 6 foot cable.  The product reviewer needed a longer cable in order to
perform his testing, so he asked a friend to figure out the wiring scheme. 
The "proprietary format" turned out the same pinout as a CAT 6 patch cable.

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