Pass Labs int 60 vs. Luxman 590 uX ii

Builer,

It's a little more subtle than that.  Most amps will double in power as impedance is halved.... down to a point. 

From 32 to 16 to 8 to 4.  That's Fairly typical for most amps to handle.  As the speaker impedance gets close to the amp impedance though, this vanishes.  The power never gets to the speaker, and things sag.

It's my experience throough a lot of listening and cable comparisons, that amps _can_ be a little more sensitive to this problem, cable and speaker impedance, than we have thought.  How much it is worth to fix, whether it is bad, and what a particular amp/speaker combo will sound like is another matter.

I am a Luxman pusher.

Everything else is projection. :)

For some one who loves Pass, you just did Pass a huge disservice.

No modern amp company I know of has innovated along the lines of amplifier circuits more than Pass.  Attempting to reduce a Luxman vs. Pass to Bipolar vs. MOSFET trope is something no one should do.

Pass very much has a unique sound which has attracted many (not me) and it's nothing to do with how MOSFETs sound.

The Pass sound is unique by design, and it's not just the choice of devices used.

Hi  builder3

Again, want to emphasize that what's important is the performance, not the theory, but here goes.

The lower a speaker's impedance is, the harder to drive, the more likely an amplifier is to sag, or produce less output in that region than the rest.  The "ideal voltage source" theory, where the output is the same across all frequencies, regardless of impedance, will always fail if the speaker impedance is low enough. 

Here are the measurements for the 1037, which lets us talk about this with specific frequencies in mind:

https://www.stereophile.com/content/focal-electra-1037-be-loudspeaker-measurements

For this particular speaker, the hardest areas to drive are between 30 Hz and 300 Hz.  In this case the issue is more towards the true bass than mid bass.

Focal tends to make speakers which are "demanding" for amplifiers, especially in the bass/mid bass region.  Since bass is the largest signal swing in music and the impedance is lowest there, this is a tough to drive speaker.  Not as tough in absolute terms as others, but difficult nonetheless.  To some, these speakers will appear "discerning" of amplifier, and I worry audiophiles take it to mean they reproduce music better. 

In any event, where the impedance sags below 4 Ohms is a place to listen when comparing amplifiers.  However!!! Just because it produces less bass, is not disqualifying, you might like that, and it may make a better amp/speaker/room match.

Doh, I retract my retraction so deleted it. 

Here's the piece I find important.

Per Luxman's website, the 590 has:

Bipolar 3-parallel push-pull

But the 509 has:

Bipolar 4-parallel push-pull

Implying a lower output impedance.

Is this critical?  No, but my experience is that amps are more sensitive to a speaker's impedance than we believe from the pure math. On the other hand, the 507 also has only 3, and I find it very capable, but .... my speakers have a higher minimum.

So, if you had the chance to listen to both, I'd 100% recommend you listen to what happens in the mid bass as a factor to consider.  It may be zero, you may even like it.

Also, yes, the 590's actual power output for music listening will be the equal of the 509/507.

Best,


Erik

I don't know the Aesthetx, but the Focals tend to be very airy but also "revealing." Maybe TOO bright. 

They are also challenging in the mid-bass due to low output impedance they tend to put there. 

This is really going to depend on your listening style.  If you like full range music, the Luxman.  If you like low level listening, something that's going to sound better turned down, the Pass.

Also, due to the low impedance, you may be better served by the Luxman 509 thanks to the robust output stage.  I could be wrong here, but I think it has more output transistors.... I'd have to do more research to find out.

In any event, I strongly encourage you to listen.  You may find your tastes are the opposite of mine.