Effect of amplifier slew rate on planars.....

ashok

Member
2002-06-06 4:43 am
3RS
I came across a post on the Yahoo Luxman forum about a Magnepan sounding best with amplifiers having a high slew rate .

here are some extracts
"................own a pair of Magneplanar Tympani IVa .....................

( have a )...complete Tri-amplified Luxman LRS system and a couple of Mark
Levinson LNC 2 crossovers. Also have a Levinson ML-1 pre amp and 6 ML-2 class A
power amplifiers. The Luxman LRS wins hand down, but that is because the 5M20 / 21 has
such a fast slew rate, even faster than the Levinson..........
-----------------------------------

Is this performance improvement just because of slew rate or other parameters ? Any opinions ?
 
It is not a matter of opinion.

See here for a simple explanation of slew rate:
http://www.consultrsr.com/resources/pstats/bwidth.htm

As you can see, slew rate is essentially the same thing as bandwidth. Bandwidth is translatable to frequency response.

Therefore, slew rate determines the upper frequency response limit of an amplifier.

Speakers don't care what the BW of an amplifier is. Your ears care. If your amplifier has adequate bandwidth to reproduce the audio spectrum as defined by your ability to hear there is no need to go beyond it.

Yet another planar speaker myth created by marketing people who know nothing but possess great skill at manipulating customers and believed by the gullible.

I_F
 

ashok

Member
2002-06-06 4:43 am
3RS
Thanks for your reply.
It's not that I don't know what slew rate and bandwidth is all about.
The poster was talking about extreme slewrate which would make the bandwidth far beyond the audio range and I couldn't see how that would audibly improve matters in a planar.
So I was trying to understand if there is any other mechanism that I had overlooked !

I guess your reply was a general one for all. If it was just directed to me and you said all you did , maybe you aren't familiar with me ........

:D

Thanks anyway.
 
Likely what is happening is that the effect of a very high slew rate is to make the leading edge of a square wave reproduced on such an amp look rather "sharp" - in some implementations of circuits that are "fast" one might get an effect where there are some HF artifacts that make the amp "sound faster"...

That's the only explanation I can come up with...

_-_-bear