David Looser wrote:

Indeed, excessive bandwidth of the incoming signal.

Excessive slew rate. There really is no other adequate way
of saying it. Not excessive bandwidth, or amplitude, or
combination of the two, but slew rate, pure and simple. A
signal of a particular frequency has a max slew rate which
depends on its amplitude, and vice versa, so neither
frequency nor amplitude alone define a slew rate. Although a
particular combination of frequency and amplitude defines a
maximum slew rate, it isn't a unique definition because it
could be the same for any number of other combinations and
waveforms.

But as Jim showed a simple passive filter on the input to
the amplifier solves it.

Not if it's bad enough so that it can occur at audio
frequencies, or frequencies otherwise necessary for the
satisfactory operation of the amp. Then the cause of the
limiting must be dealt with.

Ian

"Ian Iveson" wrote in message
...
David Looser wrote:

Indeed, excessive bandwidth of the incoming signal.

Excessive slew rate. There really is no other adequate way of saying it.
Not excessive bandwidth, or amplitude, or combination of the two, but slew
rate, pure and simple. A signal of a particular frequency has a max slew
rate which depends on its amplitude, and vice versa, so neither frequency
nor amplitude alone define a slew rate. Although a particular combination
of frequency and amplitude defines a maximum slew rate, it isn't a unique
definition because it could be the same for any number of other
combinations and waveforms.

Absolutely, I'm not quibbling with that.

But as Jim showed a simple passive filter on the input to the amplifier
solves it.

Not if it's bad enough so that it can occur at audio frequencies, or
frequencies otherwise necessary for the satisfactory operation of the amp.
Then the cause of the limiting must be dealt with.


Well OK, if it's *that* bad!

David.

In article , Ian Iveson
wrote:
David Looser wrote:

Indeed, excessive bandwidth of the incoming signal.

Excessive slew rate. There really is no other adequate way of saying
it. Not excessive bandwidth, or amplitude, or combination of the two,
but slew rate, pure and simple.

Although as IIUC you indicated earlier, the input slew rate that does
become 'excessive' will also depend on other factors like signal amplitude
if - for example - the output load also has resistance as so that takes
some of the output current.



But as Jim showed a simple passive filter on the input to the
amplifier solves it.

Not if it's bad enough so that it can occur at audio frequencies, or
frequencies otherwise necessary for the satisfactory operation of the
amp. Then the cause of the limiting must be dealt with.

Well, the fix could prevent the slew limiting, but at the unacceptable
sacrifice of spoiling the performance in another way (i.e. rolling away the
HF to an audible extent). So, yes, the design would need altering in some
other way to avoid exchanging one problem for another.

Slainte,

Jim

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