Pass Labs int 60 vs. Luxman 590 uX ii

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

Can you elaborate on your statement regarding the mid-bass, Erik. I'm not sharp enough to know what you're getting at.

Maybe related, maybe not, but one of my first impressions with my amp was how well it took control of the bass. Admittedly, it was a huge step up from my prior (antiquated) piece.

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.

builder3 Can you elaborate on your statement regarding the mid-bass, Erik.

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.

This is bi-polar v mosfet and the lower output impedance (amount of damping factor) can be a bit of a furphy builder3.
As the damping factor also comes down to the amount of "negative feedback" used (global or local), and size of the output resistors the output stage has, to what amp has the "lower output impedance" (better damping factor) it could very well be the Pass Int-60.

Cheers George

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.