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


Hello everyone, I have question that I hope some of you either can answer or have an opinion on. Ever since I was 17, I have always wanted to own Audio Research equipment. I’m 56 now, and finally was able to fulfill my life long dream. My first acquisition was an ARC LS15 pre-amp bought here used in mint condition. I paired it with a Vincent 331MK hybrid amp also bought here used in mint condition. The resulting sound was impressive. After that, I started looking for an ARC amp I could afford. The resulting search found me an ARC VS115 amp also here in used, awesome condition. This is where my problems and my doubts started. Upon hooking up the amp to my system, a tube in the left channel arced and blew a resistor. I had to take the amp to an ARC dealer and he installed a new resistor and suggested I buy all new tubes from ARC for the amp. I did and when I got back home, I again hooked up the amp and immediately upon turning the amp on, I started to hear thumping sounds coming from my left speaker, then, two left channel output tubes started to glow a very bright orange, and then white smoke started to rise from one of the tube sockets. I immediately turned the amp off. I called the dealer and he suggested I mail the unit back to ARC. I did and I am now waiting to see what they say.

During this time, I started to search out other brands and came across one called PrimaLuna. I have watched their videos and seen them compared to ARC equipment. Their build quality seems to be superior to ARC and the reviews are over the top. I am looking at their Dialogue Premium HP amp and their Dialogue Premium pre-amp. For what they cost, considering how they are built and supposedly sound compared to units costing 3 to 4 times their price, they almost seem too good to be true. Anyway, my bubble has been burst, and in simple terms, I am considering jumping ship and going with another company instead of ARC, despite all those years of drooling and waiting.

My main question is this, is there anyone out there that either owns PrimaLuna or has had experience with the equipment and can give me their opinion on owning and using it. Then, my second question is how does PrimaLuna really compare to other high end equipment such as ARC. Kevin Deal in his videos on PrimaLuna makes a very compelling case for the equipment. In one video, he compares an ARC LS17SE to the PrimaLuna pre-amp.

My last question is in regards to my ARC VS115 amp problems. Anyone have an opinion on what is going on with my amp or a VS115 in general. For those of you who want to know what else is in my system, I am using KEF 104ab speakers, a Cambridge Azur 752BD Blu-ray player as my CD player, Morrow Audio Cables and I am considering getting the Sony HAP-Z1ES music player for my digital files.

I greatly appreciate all who take the time to comment and give their opinions. I will be glad to answer any questions you may ask or provide additional. Thanks for your help. Steve.


128x128skyhawk51
That's just silly. Many dealers have good listening rooms and an audiophile can certainly make an initial evaluation there. Sometimes it's easy to ascertain that an amp is too bright, or lacks bass, or is just in some way not to the liking of the listener.

All of those characteristics can change by moving a speaker an inch. Raising or lowering volume a few dB changes everything about perception of sound.  Fletcher and Munson figured that out in the 30's.  

Picking out speakers?  Of course.  You must listen. Amps?  Level-matched, same room, same speakers.  You're kidding yourself otherwise.  

Looks like I have at least one or two guys willing to come out.  I can even demonstrate how your mind can get tricked if you want.  My loving wife will feel abandoned, but I can meet tomorrow anytime or Sunday if it's early.  Next weekend I can meet Saturday the 15th or earlier Sunday.  

Check your calendars if you can please.  Most happy to host you.  I love dinking around with gear.
Kevin to ME being an audiophile among other things unrelated to musical enjoyment is discerning subtle differences of a given component through all the variables and proceeding from THAT point. I've been an audiophile long before I ever heard the term, careful listening is the key as you well know being a dealer. It is, to me at least,  much more than level matching of two components in a given system. Often there are other considerations and aspects revealed to an experienced listener. Point being we all process info differently, what's obvious to you may be less so to me and conversely. I trust your method for you but mine for me, all that matters in the end is the result, right? I do however agree that level matching makes discerning a bit easier for sure but not necessarily essential for some. Yes our mind can get tricked for sure or else why so may cable manufacturers'?🤔
upscaleaudio07-07-2017 12:51pm
All of those characteristics can change by moving a speaker an inch. Raising or lowering volume a few dB changes everything about perception of sound.  Fletcher and Munson figured that out in the 30's.

Picking out speakers?  Of course.  You must listen. Amps?  Level-matched, same room, same speakers.  You're kidding yourself otherwise.
Fletcher and Munson's work involved loudness and f-r contours; they never suggested changing volume "changes everything about perception of sound."

Your argument is also inconsistent. You seem willing to dispense with your rigid testing protocol for speakers - but why? Because it's difficult? While it's obviously a tricky undertaking, it most certainly can be done - HK has done some interesting experiments with speakers using your protocol, for example. You can't reasonably insist that your One Way of testing electronics is the only Valid Way, then dismiss your One Way method when the device under test is a loudspeaker. What's good for the goose is good for the gander.

In any event, I'd never allow an audio dealer to tell me how to listen. While I value the advice of a good dealer, I already know how to listen. But I'm not going to tell you how to run your business.
"Check your calendars if you can please. Most happy to host you. I love dinking around with gear."

Kevin, Saturday-15th clear for me. Great, if this day works for everyone else willing to come.


who was the first to show experimentally that volume was so important?

was it some dude with a big lab at Harmon?
Kevin at UpScaleAudio, here's an idea that I think many on this thread might like. If you go through with the sound challenge or something like it, make a video of it and then post it on your YouTube channel. I would love to watch the event and I bet others would too. It would be awesome and quite a learning experience. You could explain how the setup was done and the proper way of auditioning equipment and comparing them to one another. Please consider it. Thanks.
Kevin at UpScaleAudio, here's an idea that I think many on this thread might like. If you go through with the sound challenge or something like it, make a video of it and then post it on your YouTube channel.

I don't know what to put up on Youtube but I guess we could show how to A/B gear.   It isn't rocket science.  With SOME tube amps you can switch from one to another hot. 

A new employee here was doing an A/B for a customer between the DiaLogue Premium preamp and the PS Audio BHK.  The customer liked dynamic music which included hip hop etc.  I left them alone and they came to the conclusion the BHK was MUCH MORE dynamic than the PrimaLuna.  

I don't doubt that the two can be a little different.  The BHK is a hybrid after all.  But MUCH MORE DYNAMIC?  Nope.  I asked if they came to this conclusion in a level matched A/B...they said no.  

I used an SPL and set it up to compare the two again...and they were both shocked how wrong they were.  The louder demo will 99% of the time sound better.  Now...level matched...the customer went for the PrimaLuna though I will tell you in this case it's a difference in color. When you get to the best preamps that's how it goes.   

The best example I know of is back in the late 70's stereo stores used switch boxes to go between speakers.  If we left a customer alone to flip a switch between and choose either 88dB Advents and 96dB Cerwin Vegas....the Cerwin Vegas would always "win".  
who was the first to show experimentally that volume was so important?

was it some dude with a big lab at Harmon?

Here's some links.  Some of this is kind of propeller head.  
https://en.wikipedia.org/wiki/Fletcher%E2%80%93Munson_curves
https://en.wikipedia.org/wiki/Robinson%E2%80%93Dadson_curves

This sums it all up well below

http://www.lindos.co.uk/cgi-bin/FlexiData.cgi?SOURCE=Articles&VIEW=full&id=17

Hence the importance of exact same volume and conditions.  




I can't tell much beyond tonal balance differences in an A/B test unless other differences are rather gross.

I'm a believer in bringing a new one home, after you haven't changed your home setup in a month or more. Improvements should register fairly quickly. Sideways moves and downgrades are trickier, and should be assumed in the absence of improvements, unless you have a month to get used to the new candidate before switching back.
of course your customer went for the primaluna...........the used car salesman schtick is getting old 

Since no one answered my question about exactly who is manufacturing Prima Luna in China, I did a little research.

From what I was able to find, it seems that Prima Luna is made in the Cayin/Spark factory. Cayin/Spark is a subsidiary of Zhuhai Spark Electronic Equipment Co, LTD. which is owned by China National Aero-technology Import and Export Corporation (CATIC). CATIC is owned by the Chinese government. CATIC is a major manufacturer of military aviation products and supplies both China and abroad.  Consumer electronics seems to be a small part of its portfolio.

How important this might be to to US consumers, is, of course, personal.

https://en.wikipedia.org/wiki/China_National_Aero-Technology_Import_%26_Export_Corporation



I read some incredible reviews, and talked to audio enthusiasts who rave about the sound of ARCs new Reference series amps. Hopefully their  reliability and delight of ownership, aside from bragging rights, is on par with their sonic bliss. Previous ARC models seem to have more than their share of biasing problems and melt downs from a bad tube. It seems that, when someone spends many thousands of dollars on a piece of equipment, he shouldn't have to spend thousands more to keep it operational and spend weeks, even months with the old stand-by unit back in service while waiting for repairs.
I'm not a fan of Chinese cheep labor, but there are many very good American made components out there - some on the pricey side and others, like Rouge and Raven a bit more on the affordable side - that sound very good and don't melt down when a tube goes bad.
Jim 
...it all depends on how you value the stuff.....some people can't hear any difference ...some hear a lot of difference.   When I was in a prestigious music school for my advanced degrees, many profs.  listened to Beethoven on their Webcor portables.
Think about it this way. Would a Audio Research rep ever publicly say a Primaluna product would beat out a AR product? Or post a video of people preferring Primaluna over AR in some a/b test? Just like Kevin would NEVER do that with any of Primaluna products. So silly how this thread has become lol. It's like whose got a bigger stick. Let's all get our rulers out!
dchang if you don't have anything positive to contribute I am sure most of us would appreciate keeping your negative comments to yourself. I'm sure Kevin can speak for himself but since I have known him he has been very helpful and forthright. I believe his experience speaks for itself.  He truly is a stand up guy, believes in what he sells and will help most anyone with tubed audio. 
just because im not nutting all over PL like your posts doesnt mean I must leave this thread. im sorry but i don’t find those type of posts helpful either. giving anecdotes of a customer realizing that a $3k primaluna outclasses a $10k whatever Reminds me of bo’s posts about monitor audio. i’ve had a fair amount of ARC gear too, and while I like the sound, having a resistor blow is no fun so i understand checking out other gear. Going by what some fanboys and the distributor say on the internet isnt constructive, take some time and listen to as much as you can in person.

finally remembered why i stopped reading these forums for awhile.
@jhills, I love the auto-bias feature on my ARC VT-80 amp. I think this should be one of those 'must' have feature on every tube amp. 

Speaking of ARC reference amps, I was fortunate enough to sit through an audition of REF250SE, REF6 with Sonus Faber's Lilium speakers....l was quite blown away by larger than life soundstage, imaging and a sense of realism. 
@lalitk
From what I've read and heard from others, I have little doubt of the sonic realism and incredible audio performance of the new ARC ref. series.  Does the new ARC reference amps auto-bias or can the owner, at least, easily adjust the bias at home, or change out a tube, if necessary, without sending the whole unit in for an expensive, time taking factory service? If spending thousands of dollars for a piece of equipment, it's just important to know that it will stay in service.
thanks, Jim
@jhills, 

"Does the new ARC reference amps auto-bias or can the owner, at least, easily adjust the bias at home, or change out a tube" 

Yes to all except auto-bias feature. The amp is equipped with self bias feature for all 6 valves and user can easily adjust or tweak bias level with flat bladed bias tool provided by ARC.  

@lalitk  and @jhills
Another point about the auto-biasing is that you can roll in a number of different tubes (I'm sure you know this lalitk, but for the benefit of others....). The ARC sales sheet mentions that you can use 6550, KT88, KT90, KT120 (comes with), and KT150 tubes. This feature works in real time and is said to introduce no performance compromise.

Another new feature is that each of the tubes are fused and so there is not a sacrificial resistor. So it sounds like the VT80 will be much easier to service at home now.

Finally, I know I mentioned this but I've heard the LS28/VT80 combo with Wilson Audio Sabrina's at LAAS. I've also heard the Sabrina's with the ARC Gsi75 integrated (same dealer/different time). Also, very nice synergy. Marvelous presentation top to bottom for both; beautiful mid's and high's; solid bass;  holographic; excellent control of the speakers. 
@lalitk
I am most anxious to hear the new ARC equipment.
Hope to have a chance for an audition soon.
Much thanks,
Jim
Speaking of ARC reference amps, I was fortunate enough to sit through an audition of REF250SE, REF6 with Sonus Faber's Lilium speakers....l was quite blown away by larger than life soundstage, imaging and a sense of realism.

That's close to my combo of Ref 6 and Ref 150SE. As soon as I have them in place with some listening time I will report back. My front ends are a VPI Prime SS Zephyr MIMC into a Manley Steelhead and an Aurender N100H into an Abbingdon Music Research DP777.
Hi guys, I'm back to report an update. During the unboxing of the amp, I had to remove the plastic bag that the amp had been put in. That is when I heard a sound coming from inside the amp. As I moved the amp back and forth, I could hear something that was loose moving. This obviously concerned me so I turned it upside down and used a flashlight to see inside. Naturally, I thought something may have broken off during the shipping. I didn't see anything out of the ordinary so when I righted the amp, that is when the thing making the noise fell out. It was a piece of plastic zip tie. I was relieved that it wasn't an electronic part of some kind. Following that, I hooked up the amp and other components, crossed my fingers and flipped the switch on the amp. It came to life with no issues, so I proceeded to wait and give it a warm up period of about 30 minutes. After that, I played some jazz from musician Peter White. For the next hour I listened to him and some other music without any glitches. So far I am happy to have the amp back and can finally use and enjoy it. As too its performance, I think I need to teak my speaker placement in relation to where I am sitting to get the best sound, but over all I am pleased by the sound. Seeing the tubes glow while listening to music is a real treat and part of the over all experience I think. That is why I like the open design of the VS115 amp. After all this time, I finally have an ARC system in my home and I look forward to many, many hours of listening pleasure.

However, during this whole process of getting this system up and finally  running in my home, I do believe that my bubble has been burst about high end audio in general, ARC equipment in particular, the industry as a whole, and the madness or insanity if you like, about how much is spent on achieving ultimate sound quality.

I think if I was starting over and hadn't been so tied to ARC coming from my past, I would have bought PrimaLuna instead for several reasons already spoken about in this thread. Considering their build quality and price, I sure I would have been more than happy if them. I think I will try them sometime in the future and compare them to ARC. I am willing to bet I may prefer them. When it comes to high end audio, I do believe we come with a set of biases that influence us in our purchasing decisions. Such as, if it cost more, it must sound better. If it is made in USA, it is better. If it says a certain name on it, It is better. All of this then lends itself to bragging rights when describing our system to others. And thus, this gets passed on from one person to another.

And finally, when you consider all the variables that exist when comparing equipment, how can you really be sure that something really sounds better or it just sounds different. You could spend all day listing those many variables that come into play when comparing equipment and when you take that into account, I think that is where the insanity of it all comes into place. People in this hobby will spend 5x the amount to achieve a perceived improvement in sound quality that may or may not really be there. And if it is, can it be heard by the person making the investment due to all the variables that exist.

I am sure that this has been discussed many times before and will again. When you think about it, this could be one of the main reasons that drive the hobby and industry which is the pursuit of the holy grail of high end audio. Hearing live music with all its nuances in your home from recorded music played on audio equipment.



Skyhawk-please keep in mind that the VS115 came out in 8/2018. Amp technology may not change that much but parts quality keeps improving. Plus, how many owners owned your VS115 before you, how did they treat it, and how many times was it shipped? And btw, the LS15 came in two versions, one better than the other. Which do you have. Neither come close to the LS18. Sell 'em off, buy the PL stuff-I bet it sounds great- and report back. But all that said, your mental construct-just my worthless opinion-is a bit skewed. Skewed because ARC gear is dependable (all of PL's marketing has zilch to do with preventing tube arc) and because the critical parts of recent vintage ARC gear is far superior to that of PL.
fsonicsmith, I appreciate your response. I think your date on when the amp came out though is a little off. I checked and I couldn't find an ARC LS18 pre-amp. Was you referring to the LS28 model?
Should have read "LS 28". Date wrong, no; the VS115 came out in Jan 2008, just shy of 10 yrs ago. I ask again-how many owners before you obtained it? How do you know whether it saw gentle use or hard? How do you know it had been shipped properly each time?

fsonicsmith, as to the date you first gave, you wrote 8/2018. I read that as August of 2018. That date has not happened yet. My preamp is the LS15SE version. Bought the amp from a person who claimed he was the first owner or the second owner. Been too long too remember. He was an avid ARC customer and was upgrading to more expensive ARC. The amp came to me looking in mint condition. I believe that this all started from bad tubes and not the amp itself. However, due to the amp's design, it led to my other problems I had with it which led me to start looking at other brands which led me to PrimalLuna and comparing how they are built and at what price.

Welcome to the world of high end audio.  High end cars, high end watches, etc. 

1) when spending money, it is the responsibility of the buyer to do their homework and know that you get what you pay for and the more research and testing you do the safer you are.

2) typically (not always), expensive equipment, especially equipment that is highly technical and delicate, require more high end maintenance and it more costly to maintain.

As an Electrical Engineer, I can tell you that no matter the manufacturer, parts fail.  Deal with it.

Same with cars.  Parts fail. There is no such thing as a 100% reliable anything. 

I believe in this case, the item was purchased used, without warranty.  That, to me means that you really don't know how the item was treated or used in the past.  It is like buying a really nice fast expensive car with very low miles.  You might think you are getting a real bargain, only to realize latter that the first owner really dogged  that car.  Raced it, etc.  So, just because it has "low miles" doesn't mean it wasn't abused.

Audio Research, like some other manufacturers makes some high quality equipment.  That does not mean they won't fail at some time.  Remember, Audio Research does not make the tubes.  they can test them till the cows come home and evaluate the tubes to death, but since they don't make them, it can't be totally their fault if a tube fails prematurely.  That is why there is a warranty period.

Audio Research will repair all the equipment that they have made from day one, with exception of maybe one or two where parts are no longer available or where they don't have the parts in stock anymore and they are no longer available.

Airplane manufacturers build the planes.  They recommend engines for the buyers.  If the buyer choses to purchase and have installed other engines contrary to the plane manufacturer's recommendation, is it the plane manufacturer's fault if the engine fails?

Sorry for the lengthy rant, but, I have seen numerous posts negative to Audio Research and they all end with it really not being Audio Research's fault.  One was the fault of the distributor. This one could be the previous owner's lack of proper use. 

but, my ultimate test, knowing that stuff happens and things break no matter how well designed, it when I send it back to the manufacturer for repair.  How is the repair work?  Does the unit work well now?  if so, that is all I care about.

but, for people to think that things won't fail at one time or another, or for them to be angry or disappointed when it does occur, it really not realistic or reasonable.  This is why proper maintenance and servicing is so important.  It helps prevent failure.

most people wait till something fails. not cool.

Primaluna may make some good equipment.  I don't know.  However, how would you feel if you purchased a Primaluna piece used and it failed?  Is that Primaluna's fault?  maybe not.

I'm at the point where I really want to buy from manufacturer's with good track records related to repairs.  Martin Logan still makes panels for much earlier speaker models.  Audio Research will repair just about every piece they have made.  Same is true for Atmosphere and some others. 

Take it slow, enjoy the music

mlnorl,

Wel said. Thank You. I try to ignore the whining.

Space Shuttles blow-up.
skyhawk51 I would just relax and have fun. You have a nice amp and preamp, and I suspect you will get many hours of enjoyment from it.  In a month or so all this angst will fade I suspect.  

Some amps don't have plate fuses and rely on sacrificial resistors.  If the amp breaks again fix it yourself.  It's not that tough. Or find a local tech. Tube amps are very simple by nature.   

My biggest hope is that people try owning tubes at least once in their life.  I would rather have a very good $2399 tube integrated over a $20,000 stack of reference solid state separates.  I mean that. If I had only solid state my listening would drop by 50%.  Or more.  

 
Funny I have always had tubes in my rig. Like tube gear. Now no tubes and I listen even more. Depends on the system put together and it's resulting sound. Not a tube vs. SS issue always. We listen to complete systems right? 
It's official.  We will do an precise level-matched A/B comparison of the ARC VSI75 and the DiaLogue Premium integrated amps.   Also attending is Bob Levi President of the L.A. and Orange County Audio Society.  

Both are fabulous amplifiers.  We'll meet at 10 am this Saturday.  Can a couple of you guys come?  It's open to all.   
I bet the PL sounds as good or better. But what about your Dialogue Premium pre and amp separates vs. an LS28 and VT80?
Kevin,

Any chance you might be able to record the event for your youtube
channel? I certainly would be
"It's official. We will do an precise level-matched A/B comparison of the ARC VSI75 and the DiaLogue Premium integrated amps. 

I think thats a great choice for a shootout Kevin, count me in. Since  I have the HP and have admired the VSI75 since it was introduced, I'm curious to hear the differences especially since I was considering a used piece without ever auditioning one.  

Should be interesting and surprising?

I actually do like almost all ARC amps I have listened to, but have always found the pricy. That being said, when buying a new pre I went Mac 2500, itself not cheap, but tubed. I also have a PL Dialogue 5, in which I have had the pleasure of doing an awful lot, probably 8-10 different sets, of tube rolling.Great Play!! Rolling included but types and brands, mostly NOS and mostly NIB total cost far exceeding the amp price.

I also have an Audispace, that was mentioned above as high quality ChiFi and I love it and concur with that assessment. However the PL has amazing breadth of sound variation, tube dependent, and all clear crisp and musical. I also like this amp a lot. I have the Mac also connected to solid state monoblock, and I can switch between amps via integrated switch, so easy to compare.

With most tube combos the PL has an added sweetness than just the tubes in the MAC alone provides. However the MAC with solid state amp may be crisper, so I can easily understand people having a preference for either combo....tube pre solid state amp and tube pre tube amp. I like tubes and PL is a winner with the best tubes you can get, a a solid Pre. Just my 2 cents.
upscaleaudio
It's official.  We will do an precise level-matched A/B comparison of the ARC VSI75 and the DiaLogue Premium integrated amps.
This is interesting! Can you please tell us more about how the test will be conducted? Will it be double-blind?

I want to work with the best time for everybody.  Bob Levi says he will be here at 10AM.  It's so blasted hot in California now it's hard to do anything during the day but stay in and listen to music.  I would almost like to say 11AM so I can go for a motorcycle ride in the morning.  I'm easy.  

Who can come, and what time is best?

You guys tell me what works and I will ask Bob too.  It's this Saturday.  I'm going on vacation the next Saturday.  I'm going to the Focal factory in France to take a tour which from what I hear is incredible, then after that meeting with Herman from PrimaLuna.  

As to filming the meeting we have here, not sure what you would like to see.  Tell me and I can try.  I don't have employees here Saturday but maybe I can get the wifey to do it.  
This is interesting! Can you please tell us more about how the test will be conducted? Will it be double-blind? 

The way I do an A/B is first I play music at a healthy volume suitable for listening and evaluating on one amp.  Then I play a test tone and use an SPL meter to measure the volume.  I then hook up amp B to the same source, play the same tone, and adjust volume on amp B where it's playing at the same volume as amp A within 0.1dB.  1dB is close, but 0.1dB or 0.2dB is the best if you can make them that close.  

Then while both amps are hot, play a track on amp A, move the source and speaker to amp B, and listen.  Simple.  Same cut.  Same volume. Don't even turn off the amps.  Instant.

I suspect that the difference will be quite noticeable, so double blind really isn't needed like you do with cables and tweaks.  
Wish I could be there - too long of a trip from NH!


Come on out to L.A. Greg!!  As an added bonus, we'll get you signed up with the religious cult of your choice, get you in a high-speed chase, or a fire just for showing up!!
Now that's funny!!

Kevin, what speaker and source will you be pairing with these integrateds?

"I want to work with the best time for everybody. Bob Levi says he will be here at 10AM. It's so blasted hot in California now it's hard to do anything during the day but stay in and listen to music. I would almost like to say 11AM so I can go for a motorcycle ride in the morning. I'm easy."

Who can come, and what time is best?

Kevin- the freeways shouldn't be too bad for my hour drive,so whatever time works for everyone else is fine. Looking forward to listening to some interesting results. I think I know what I may find more engaging, but I'll save my opinion until I hear the truth.



Kevin, what speaker and source will you be pairing with these integrateds?


A PS Audio Directstream DAC as it has an excellent output section, and at the moment we have Focal Sopra 2's set up PERFECTLY in our bigger room and they will be revealing for both top end and bottom end reach.  
Tablejockey, musicpod and fsonicsmith?  

I had a customer contact me through e-mail named Mark N.  Is that one of you?  
Hi Kevin,

Myself and a friend will make the hour or so drive for this shoot out. We can be there around Noon. Let us know what the consensus on timing is.

"Tablejockey, musicpod and fsonicsmith?  

I had a customer contact me through e-mail named Mark N.  Is that one of you? "

Not me, Kevin.

Kevin, sorry if I missed this in the mix of back-and-forths...I presume the two amps for the comparison will be using roughly the same tubes, or hopefully at least the same output tubes, anyway?  What are in each instance--KT150s?  I also presume both are going to be broken-in versions of the amps and the tubes?