Haven't heard the ARC Ref 3 preamp yet. Only the ARC LS27. Anyway, has anyone out there ever tried replacing the Sovtek 6H30 tubes that comes with the LS27 with the Reflector 6H30p-DR tubes? Did it with mine and it sounded so much better. More full bodied, wider and deeper sound-stage. All in all, sounded better in all departments.

how many hours were on the Sovteks when you swapped them out?

3000 Plus.

A bit of off topic. Has anyone out there ever compared the AR Reference 5SE to the AR LS 28 preamplifier? If yes, how do they compare to each other? How do they differ in sonic character and which do you personally prefer between the Ref 5SE and LS 28?
Thanks in advance.

As an intermediate step, doesn't ARC offer and SE upgrade for both the LS27 & LS28?

I have both in the store. The LS28 is surprisingly close to the Ref5SE. The whole unit is sooo light compared to the 5SE, I wondered what they padded the Ref5SE with

To understand you correctly, the 5SE sounds a bit better than the LS28? If yes, in what way?
Thanks.

LS-27 compared to REF 5-SE
 

I have made a lengthy comparison between the 27 and 5-SE in combination with my REF 75-SE (tried the 27 out for some weeks brought it back, tried the 5-SE, switched back again and os one for couple of times.).
Really wanting the 27 to sound at least good enough because of the price difference and the fact that the 5-SE did not fit my cabinet.
In the end I decided for the 5-SE. The 5-SE just sounds much wider, natural, has more detail, live, fun..... it is much better in every way. Have the 5-SE now for about 2 years, still pleases me every time I turn it on.

Gain diff
 

LS27 owner here, I have not audition 5se, but I can tell you depends on the setup in LS27, it can sound quite diff.

By default it has 24 bal n 18 se in high(what I feel unrestricted) gain. Thats way more than most ppl need. So most setup would have it on low gain.

I read at least in one review, arc told reviewer to use only high gain. Which led me to believe the gain selection might actually impact the sonic signature. So I actually got a khozmo resistor based passive preamp to test it. Using passive in front of ls27 allow me to use the high gain and full range of vol with 1 resistor more on the signal path, and sounds more full and organic. The dac I use is r2r holo spring.

5se otoh the output gain se is higher than bal, and with lower 12 n 6 gain, its quite different.

I totally agree. I own a Ref 5se and have had an LS27 in my system for a couple of weeks on two different occasions. The Ref 5se is better in every way and not by a little bit. In my system the LS27 sounds thin It lacks the depth and richness of the Ref 5se. But then at twice the retail price it should sound better.