From: utzoo!decvax!harpo!eagle!mhuxt!mhuxj!mhuxi!cbosgd!npois!houxm!houxa!houxi!houxz!ihnp4!ixn5c!inuxc!pur-ee!uiucdcs!emrath
Newsgroups: net.audio
Title: Re: connecting cables and damping - (nf)
Article-I.D.: uiucdcs.1749
Posted: Wed Mar 23 22:25:38 1983
Received: Fri Mar 25 20:05:07 1983

#R:dvamc:-104300:uiucdcs:22700010:000:1989
uiucdcs!emrath    Mar 23 18:27:00 1983

I tried very carefully to compare the sound from my speakers with a damping
factor of 100 (or whatever my amps are capable of-I haven't bothered to measure them) versus a damping factor of 2. I convinced myself that even if somebody
could hear the difference in an A/B compare, this difference is of NO
significance to ME, and it will be forgotten within 10 seconds of switching.
This is all strictly my opinion, and I fully agree that some people will
find special speaker cables to be worth their price.

Notes:
  1)	I always assume that a stated damping factor is a minimum over the
	audio frequency range (20-20KHz), unless otherwise specified.
  2)	As for losses, using a .639 ohm wire (100 feet of 18 Ga. copper @ 68
	deg. F) with 8 ohm speakers causes less than a 10% drop in current,
	which is a loss of less than 1dB (i.e. inaudible), and a damping
	factor slightly greater than 10 (assuming output impedance of amp
	is much lower than that of wire-it generally would be).

By the way, I am currently using a homemade amplifier (not the amps mentioned
above) which is 1 Watt per channel.  The amps clip at 4.9 volts into 8 ohms
at 50 Hz, both channels driven (same phase).
I built my own LED peak indicators. Yellow triggers at +/-1.33V, red at
+/-4.0 Volts.  (a 4 Volt 0-peak sine wave is 1W rms into 8 ohms).
Attack time is less than 50 microsecs. An overvoltage of this duration
guarantees that the LED comes full on for at least 25 millisec (which is
quite visible). I sometimes turn the volume up to where the yellows are
flashing, but I seldom turn it up to where the reds are activated. In
testing, I found that I could raise the volume 12dB above that level which
never triggers the reds before I could perceive the distortion, even though
I knew damn well the thing was clipping! I originally built this thing
as a headphone amp, but it worked so well with my speakers (Pioneer CS-63s
kind of old, but rather efficient) that I have been living with it for almost
a year.