ARC Ref 5se inferior to LS28?

“I will say, it is 90% of the REF6 that replaced it in my system”
+1, @docknow. 

I purchased LS28 after auditioning both at my dealer. And I didn’t think the subtle improvements I heard with Ref6 were worth twice the price. Having said that, if Ref6 was at $10K price point, I would have grabbed Ref6 in a heartbeat. 

I am very happy with my current setup of DAC9 > LS28 > VT80. 

docknow

so in your system a fully broken in LS and REF 6 are 10% different

In my experience the REF's are always better than the LS's.  I think this tactic is a gateway to get you out of your old REF, into the current LS and then ultimately to the new REF.

The tubed power supply is significant.

@hk_fan , +1. Mere marketing tactics, nothing more.
ARC seems more prone to this hyperbole, and model turnover, than other companies though.

Now that is not to say that the LS models aren't 90% of the performance of the REF models. The law of diminishing returns hits very early in audio gear, and no manufacturer is immune. I would bet that the REF 6 gives you 90% of the performance of the REF 10.

My Transfiguration Phoenix S cartridge gives 90% of the performance of the Transfiguration Proteus. The same for my Allnic H1201 phono stage, 90% performance level of the Allnic H3000. Etc., etc., etc.

In the end, most folks pay a LOT of money for that small increase in performance. How much difference they spend, depends on how much they value the dollar versus how much they value the music.

It's an individual choice that we all make.

Manepan is a speaker manufacturer, blind tests its products and will claim that their new current lineup is slightly or signficantly superior to their older, discontinued lineup, and they have been in business a very long time.

They will use an "i" for an incremental upgrade and change the digit for a bigger upgrade.  They will ALSO tell you (as Wendell told me) "maybe you just want to keep your old ones).  They are a Minn. firm, located near ARC.
ARC seems similar to me (despite being sold a few years ago).

Tube tech. has not changed a lot but ARC does change to different circuits and different models of tubes.

You can compare the added features of ARC products at the 3rd party web site that tracks all their products - things like relays to reduce signal paths, thicker case material in places to reduce resonance (and changing from Al tops to poly-carbonate), better tube and component matching, etc. etc. all could improve SQ.  Tube hour meters can help yo achieve better SQ too.

Do a real listening test (blind) to see if you want the latest and greatest.

Don't forget - they service everything they EVER made - dos that have value to you?  Only Bryston has a better warranty/service policy AFAIK.