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Mark Zacharias Mark Zacharias is offline
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Default What's with all these new SIXohm Stereo Speakers coming out?!

"Trevor" wrote in message
...
On 10/12/2014 11:21 PM, Mark Zacharias wrote:
In my experience the manufacturers are simply trying to reduce the
number of warranty repairs to some extent by specifying the higher
resistance. In truth, with a bit of common sense applied at the volume
control side of the equation, a four-ohm speaker will work just fine
with any solid state amp or surround receiver of even minimal quality,
such as Pioneer, Sony, Marantz, Denon, Kenwood, etc PROVIDED as I say,
some common sense is used and the user isn't trying to use the thing as
a sort of mini-PA system.

Problem is, people connect all sorts of speakers, even for example car
stereo speakers wired in unusual, often incompetent ways, then expect to
be able to blast away for hours on end.

Yamaha, for example, knows full well that one of their power
transformers will not have a failed thermal fuse in the power
transformer in the absence of customer abuse - playing the thing at a
very high level, probably with low impedance speakers (or combinations
of speakers) for an hour or two more or less continuous.

Therefore, they will only cover ONE power transformer under warranty.
The warranty servicer is expected to educate the customer that a second
transformer won't be covered.

In fact, the newest Yamaha's will "rat out" the user by recording how
high the volume was for more than one minute and how many times. This
info is accessible in the service menu.



Amazing isn't it that a manufacturer can incorporate watch dog electronics
in a receiver, but not simply a more sophisticated protection circuit to
prevent damage in the first place!
I'd be looking elsewhere if that's the case.

Trevor.




Oh, they have protection circuitry all right. Lots of triggers all monitored
by the microprocessor. Problem is, since music can be extremely dynamic in
nature, and since transistors can be destroyed so quickly, any circuit that
would absolutely prevent damage to output transistors caused by abuse, would
also protect the amp from being able to produce music at any decent level.

Some manufacturers are now monitoring temperature of the power transformer
as well, but I've already seen one where the transformer was not saved from
the internal thermal fuse opening.

They're getting better, though - I'm seeing fewer and fewer blown channels
due to abuse these days.


Mark Z.