From: digilyd@hotmail.com
"Mark Zacharias" skrev i en meddelelse
news:548398d1$0$13296$4c5efc6d@fastusenet.org...
> What I meant to suggest is that so-called "8-ohm" speakers have always
> actually been closer to 5 or 6 ohms. Should have been clearer.
And this is because the loudspeaker impedance spec still just tries to tell
you what tap on an output transformer it is suggested that you should use.
It does however appears to be so that some manufacturers "slide" some of
their "8 ohm" designs down in load impedance to get them just a wee bit
louder in practical use because it allows them to use less magnet or because
more magnet does not fit the chassis well, as could be the case with the
Coral 8F60.
Unfortunately it didn't have the powerhandling to match the increased power
drawn from the amplifier and/or was optimistically spec'ed by Coral, be
warned ye that gather Coral stuff, divide its powerhandling spec by 2 or 3,
there are no more repkits, even if the 2420 kit will fit a M100 physically.
I don't really know whether they also get away with using less copper, that
would be a win win. But I wonder, I remember Dick Pierce explaining how
design parameters fit in a way that suggests that a nominal 8 Ohm design is
the most cost & power efficient.
On a more serious note: transistor amplifiers should be able to drive half
the nominal loudspeaker load because that is how the real world loudspeaker
load is likely to look anyway once phase between voltage and current is
allowed for. Note that this phase angle issue between voltage and current
means that the zero crossing in AC is an unplesant place to be for an
amplifier with current being ordered from the loudspeaker and no output
voltage available.
> mz
Kind regards
Peter Larsen
--- SoupGate-Win32 v1.05
* Origin: you cannot sedate... all the things you hate (1:229/2)
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