Power versus Sound

[Rob Dingen]

Hi

If you want more power from a amplifier you just ad some devices and more voltage on the powersuplly.
But what happens to the Sound.
Does a XA30 sound better ore worse than a XA200.
Because when adding more power mosfets you als have to drive them and the amp wil be slower and have less bandwidht.
So wat's your opinion on this are you going far a small XA with only 4 mosfets or a big one with 32 mosfets.
Don't ask me how much power I need that's not the discussion but give some experience about sound between those 2.

Rob

[GRollins]

It's not that easy. Sound quality doesn't just come down to a question of power. If the power of an amplifier was the sole determinant of how it sounded, then everyone would either be building very small amplifiers or very large ones.
A partial answer is that different amplifier topologies have different sweet spots. Topology A might sound best at 30W, with topology B giving its best sound quality at 200W. Nelson says that to him the X-600 is the best of the X series, yet he prefered the Aleph 2 (100W) out of that series. The Audio Research D-79 (75W) was legendary, but it was the Premier One (200W) that really put Conrad Johnson on the map. I think statistically you'd find that a lot of the most famous amps tend to cluster in the 50 to 75W range, but there are enough other good ones outside that spread that it's clear that the bell curve is not sharply peaked. The SET crowd are fond of amps in the 5-10W region, for instance.

Grey

[jwb]

I tend to agree. The best sounding amp is the one that's built with your speakers in mind If your speaker has a flat 8Ω impedance from 0 to 100kHz, you can drive it to deafening levels with a 20W amp easily. But what if your speaker dips to 1Ω at 200Hz? Then your amp might run out of current supply. What if it peaks at 12Ω at 2kHz? Then the amp might run out of voltage. In either situation it will clip, and sound bad.

So the appropriate amount of power will depend on the upper and lower bounds of load impedance. An amplifier that can easily deliver the worst-case current and voltage will be sufficient, regardless if it is rated for 10W or 1000W.

One of the best amp/speaker combinations I ever owned as a Nakamichi 7W stereo amplifier driving a pair of 5.25" JBL speakers in my car. It turns out that the JBLs had generally high impedance; the Nak wasn't required to deliver much current into the load. All my friends with 200W Rockford-Fosgate amps were jealous

[Rob Dingen]

Hello

I understand what you are both saying.
But let's stay with one design like the AX you can build a small one like Grey's concept or build a 200W one.
What happens usaly with the Sound if you ad more mosfets and voltage.

Rob

[uli]

Hi,

IMHO the "sound" of an Aleph(X) depends mostly on

the grade of "activity" of the VoltageControledCurrentSource.

Aleph 2 has less activity than A4 thus many people (incl. NP)

tend to like it more.

XA200 has (Np stated) about 50% activity it should sound

very well according to that "theory".

Uli