amplifier "power bandwidth" (1 Viewer)

[John Doran]

i have seen the specification "power bandwidth" for amplifiers,and do not know :

1) what it measures, and

2) how important a measurement it is.

could someone help me? thanks.

 

[ColinM]

In a nutshell, it measures the amp's performance in relation to the Hz - What it can produce and how it performs while doing it.

150w from 20Hz to 20kHz with .03% distortion would be a typical good spec, whereas...

150w @ 1kHz, .7%THD indicates that the maker only tested the amp at one easy frequency vs. the whole spectrum.

I personally consider it important to keep THD as low as possible, since it accumulates in the signal from the source to your ears. Subwoofers (I believe) are not as sensitive to distortion, it is not as audible, my opinion.

I think this answers your question....

- CM

 

[John Doran]

thanks for the reply, colin.
i'm actually not sure if it answers my question.
i have heard the term used separately from references to distortion ratings over a particular bandwidth.
bryston amps, for instance, have it as a distinct entry on their lists of specifications. (for example, see here)
and, in a review of the aragon 8008bb, john e. johnson of Secrets of HiFi, stated that

The 8008BB also has a very wide power bandwidth of 550 kHz (one of the widest we have ever measured).

which, in context, makes it sound like something different than the explanaton you gave.
you can find the review i'm mentioning Link Removed
anyway. you may still be right....
thanks again for the help, colin.
does anyone else have any ideas?

 

[ColinM]

The more I read, the more I learn.

Good replies!

 

[John Doran]

That only means that the amps output is flat (usually to within 3 db) over 550 KHz of the spectrum. That is really a very wide power bandwidth. Usually amplifers (like B&K) are flat from 20 Hz to 50KHz.

thanks for the help, mark - i actually spoke to an amplifier technician from bryston, and he basically told me the same thing.

the power bandwidth for the bryston 14b st is from below 1hz to over 100khz. if i'm not mistaken, the reason bryston's rating is so general is because, at those (inaudible) extremes, it becomes a fairly meaningless rating for an amplifier.

anyway. thanks again.

- jd