Considering switching from Audio Research to PrimaLuna, troube with VS115 amp

It was a learning experience for me too, mainly because I found that it needed to be done blinded as it's one less thing to think about during listening.  

The HP is better than the DiaLogue Premium, that's for sure.  The amps are exactly the same internally except the HP has a larger power transformer, a second Adaptive AutoBias board, four more power tubes, and the headphone capability.  

Doing this test I learned that customers do like KT150's since the $3399 DiaLogue equipped with them got the most votes.  While that's an expensive upgrade it's a LONG TERM upgrade.  The plate voltage and biasing is so easy in PrimaLuna's they go forever.  I have KT120's with over 5,000 hours on them that test at 90% of new.  My KT150's at home get used a LOT and after two years they test at 90%.  But the uptick is small, and I LOVE EL34's!   

As to comparing a DiaLogue Premium pre and HP amp to an ARC...I only have an LS26 and LS27 trade in here.  I have a VT100 MKIII that needs repair but it's not even close to being current.  If anybody has an amp they want to drag over they are welcome to.   I did not want this to be "us vs them" and I don't want people pissed at me.  

I'm leaving for France this week and will be gone until August 14th.  I'm touring the Focal factory and that's supposed to be AMAZING. Then I meet with the people from PrimaLuna for a couple weeks.   

I hope you guys downloaded that Taste of Tubes thing I linked to.  

I find the results, based on my own experiences in this hobby, not too surprising in the least. What I have personally observed over my years comparing different components is not how they might differ in a "love me or leave me" comparison but over a sustained period of familiarity. Not withstanding this it is really nice to know there are great lower priced alternatives to esteemed and proven higher priced American made for the budget minded consumer. Good job and well done to all the participants. 

One more thing I have to say about color and perception of good sound.  You can make as big an impact on the sound of your system with small signal tubes rather than power tubes, at lower cost, and in a more predictable way.  

In integrated amps or power amps it's the two input tubes.  In preamps do the gain tubes first as the cathode followers (if so equipped) have an effect, but not as much.  NOS (new old stock) 12AX7's are getting hard to find.  12AU7's are very plentiful.  6922's are still around, but starting to get more difficult.  

And if you make a mistake....put 'em in a drawer for later.  Your system may change.  At some point you will be happy you have them!!

It's been fun reading. I am not surprised at the impressions and that is meant only as a complement to PL. While I have difficulty swallowing Herb Reichert's standard deviations away from objectivity, there can be no doubt the PL gear is solid based upon the favorable comments in S'Phile. I believe that Kevin Deal and I have talked past one another on the issue of preamps but such is neither here nor there. Generally speaking, modern ARC gear tends to be fairly "in the middle" between classic tube and ss sound and I understand PL to be a bit more on the tube side of the spectrum. Prolonged time with the gear (months, not minutes) would likely bear that out. It is always possible that the Focals impedance curve lessened the difference. The critical interplay between speaker characteristics and tube amps has been explained by Ralph Karsten of Atma Sphere here; http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php
Don't get me wrong-the friendly comparison seems fine. For perfectly selfish reasons, I would love to read about a similar comparison between ARC's top gear-let's say the Ref 6 and Ref 150se vs the top PL separates. That would tell us whether PL can claim to be giant-killers-even if they simply pull even-or are instead simply great value. One related issue which brings us back to the OP, I think, has been glossed over-ARC gear has typically used resistors as the "fuse" for malfunctioning tubes but is it because ARC is just lazy/non-caring/behind-the-times or do other options ultimately degrade the signal/sound? Read any reference you wish on tube amp design-this one is good; http://ken-gilbert.com/images/pdf/taste_of_tubes.pdf and you will see that there is nothing new under the tube amp sun. So why is it that at the very same time, PL makes it sound as though it's auto-biasing and protection circuits are revolutionary? Even evolutionary? 

@tablejockey 
I used the word “unblinded” as in we could see Kevin’s making the cable swap as opposed to the blind switch where we were "blinded". 

@jbhiller 
"It seems like the takeaway is the Primaluna product is a solid bet with tons of value" I'd agree with that statement.

@upscaleaudio 
I've heard the KT150s in a few amps and always liked the way whatever amp was playing them sounded. I actually preferred the KT150s in the ARC VSi75 and felt the overall sound was very close to the EL34-tubed HP. As jbhiller noted above, there is tons of value in the Primaluna gear and when you have two pieces of gear that essentially perform the same, price should win the day.

Kevin, I also appreciate your transparency in talking about how the smaller driver tubes can make a large and significant affect on sound quality. That lets others experiment in a way that is easier on their audio finances.

Also, experimenting with tubes in Primaluna product is much easier since they have an autobias circuit; this adds to the "tons of value" in PL. -Not everyone wants to be biasing tubes.