I bought my V140's a number of years ago and have kept them a fair time considering I'm a serial box swapper. These have outlived Krell and all manor of other kit...

Initially using Groove Tube (EI) KT90's then moving on to Svetlana Winged C KT88's. I'm reviewing the amps twice based on the choice of tube. As you should know each tube has it’s own sound so be careful to evaluate an amp on what is inside it and not just on a review. In addition my amps have been fully health checked, a faulty ARC (on top of ruining hundreds of pounds of valves) may not bias correctly causing loose bass and a very poor sound. I never heard these with their original tubes fitted so can't comment on the sound with those, however they are rumoured to be bright although I cannot comment.

EI review:

The KT90 is a high power tube. I have run these with a large variety of speakers and they haven't had a problem with any of them. The ARC's don't seem to have a problem with load and don't run out of steam. The large capacitors provide a large amount of current when needed. I use the 4 ohm tap on the biggest speakers I have and 8ohms on the smaller (they are 8ohm nominal). It is very important to run the correct impedance match so you should read up on this before assuming one is best. The EI's could almost fool you into believing you're hearing a solid state amp, the bass slams (unfortunately not quite as well as Krell) and the treble is extended. The midrange gives the amp away as it beautifully etches the sound around each voice and instrument. This is subtle though, you notice it after a while as the amps suck you into the music. Unlike Krell which for me was impressive I spent more time listening to a person moving on the fourth row back in a live concert. That was off-putting, although interesting the first time round!
With the EI's I believe for once I've found a valve amp capable of rock music without the stark presentation of some solid state. Not that solid state is bad, it often portrays a superb image, stunning clarity and a full range flow that many valve amps can't manage. However the V140's manage this all with a great midrange, only loosing a little on the deepest bass, a bit of room treatment sorted that out on my full range speakers. So the EI's would be very well recommended if you find yourself loosing faith in solid state but still have an urge not to loose everything it does well. I wouldn't recommend the EI's if you're a 300B junkie, these just don't sound like that and you'll find the mid's lacking in "bloom". I also own 300B mono's from Audion so as not to sound biased here. The soundstage is as you'd expect wide and deep without that blurring of instruments when things get complex. It is very difficult for amps to pick apart instruments and less capable kit will often blur the imaging when pushed. I want the music but I don't want an orchestra sitting on top of each other. As for imaging it's as expected with the finest gear deep and wide, hiding the speakers well if you have your eye's closed.


Svetlana review:


I did a lot of research into valves for this amp after running the EI's. More as an interesting change than a necessity. 16 gloriously new KT88's arrived fully matched to very high precision. The Svetlana's are known for being very reliable, clean sounding with a great midrange. As I fancied going more "coloured" in the midrange these seemed like a good change to the EI's. GEC KT88's are stunningly expensive and getting 16 was out of my price range (not to mention the hassle), just in case you're wondering why I didn't go for those.
I was looking for a valve with more midrange magic. The Svetlana's don't have the top to bottom cohesion of the EI's. The treble, if being fussy isn't as bright, not hugely so but subtle. The bass lacked a little slam compared with the KT90's, a "warmer" presentation without lacking depth. Bass is more tuneful and tracks well though. At this level you have the right to be fussy so I'm telling it as it is. This was not as noticeable on my smaller speakers, only the full range. The valve sound moves across the frequency band far more than the EI's. The midrange fills out, meaning singers really sing the music to you, the treble wonderfully full without any smudging. Now we're getting the full benefits of valves. If you're reading this I'm sure you know what I mean. I don't really miss my solid state gear although I did enjoy it at the time.
This Svetlanas still don't turn this into a 300B, they're not overly warm and the presentation is less coloured. However there is a rightness about what you hear. Truly getting close to the best of valves without loosing the best of solid state. As most people will tell you everything in hifi is a compromise with very few products able to offer so much. Again imaging is stunning. The instruments sound like they want to be played and you can easily spend hours going through your collection rediscovering your collection and enjoying the fabulous sound. I often find with lesser amps that I'm digging around the collection for something that will sound great with the kit I'm using, none of that is necessary with the ARC's.



Summary:
Well as you can see I'm convinced that ARC have been getting things right. The kit they produce is consistently admired and they have very talented designers. So many reviews compare their kit with Audio Research, when tracking these down you won't have to. It is VERY important to make sure you get a full health check on amps like this. Valves and parts can be very expensive and taking a risk could be costly! Investing in good valves will give years of pleasure. Give the amps a full 30 minutes to get to their best. At 15-20 they're sounding great but the bass tightens up beyond this. As is I'm keeping the Svetlana's for me a wonderful match. Hope you enjoyed the review.