S888Wheel wrote:
From: "Dennis Moore"
Date: 7/13/2004 6:18 PM Pacific Standard Time
Message-id:

"John Atkinson" wrote in message
...

I have been following this thread and I don't think those who talk
about the Wavac amplifier "clipping" at 2W can have read the
review (it's now available in the www.stereophile.com archives). If
you look at the graphs of output power vs THD+N percentage, you will
see that it does indeed put out 2W at 1% THD+N, which is our usual
definition of "clipping." However, it is important to note that the
Wavac is _not_ clipping at this level of distortion.

What happens is that as the output power increases, the waveform
becomes increasingly asymmetrical, meaning that the signal
increasingly suffers from second-harmoic distortion. While this
is indeed audible once the Wavac is putting out a watt or so, it
doesn't sound like clipping distortion, particularly as it is not
accompanied by catastrophic amounts of intermodulation distortion.

As I wrote in the review, true waveform clipping occurs at a few
tens of watts, depending on the output tap and load. So for anyone
to cast aspersions at Michael Fremer's hearing ability because he
didn't hear "clipping" is inappropriate, given the particular
nature of the Wavac's non-linear transfer function.

When I listened to the Wavac, the bass boost was immediately
apparent, but it didn't sound aggressively distorted. Partly
this is because the amount of power typically demanded from an
amplifier tends to be below 2W much of the time with music rather
than test tones; partly this is because second harmonic distortion
tends to fatten the sound in rather a pleasing manner, at least
until the intermodulation products reach threshold.

Please note that I am not defending this amplifier's performance.
I am only pointing out that those on this forum who condemn its
sound without actually having heard it are shooting in the dark.

John Atkinson
Editor, Stereophile


Yes, Mr. Atkinson, you are correct, it doesn't clip at 2w. I was guilty of
a little hyperbole. Not out of place in this discussion of the $350K Wavac
I think.

I quite disagree. you had at least one other person convinced that the
manufaturers were lying outright about their product. Mr. Chung ask me what
else could the claim of 150 watts be other than a lie if it clips at 2 watts.


Let me modify the question to you then: If the rated power is 150 W and
the unit shows 2% distortion at 2 W, 5% distortion at 10 W, is the spec
a lie? If it is not a lie, what is it?