I'm sure there will be a number of worthy contendors in the forthcoming posts. Unfortunately they will only represent "my favorite(s)".
You and your system can only determine the "best".
Good luck and be prepared for some very nice recommendations.
The ARC is pretty neutral and the sound cannot be varied due to its use of 6H30 triodes -- they are only made by Sovtek.
The BAT, like the ARC, uses 6H30's, so you are stuck with its sound (which is somewhat "dark").
You can tinker with the sound of 6H30-based preamps by fooling around with power cords, power supplies, isolation components and other mods, but that is a world of chaos I try not to enter.
The Sonic Frontiers is very neutral, but its sound can be tailored somewhat through tube rolling.
As for other fine balanced tube preamps, the ARC Reference II Mk. I is very close to the best and you can roll tubes (the Ref II Mk. II uses 6H30's). The ARC LS-5 Mk. III is very good as well, and much cheaper.
Another option is the balanced (and it is truly differential balanced) solid-state Rowland Coherence II, which I own. It is quieter than any tube amp (and virtually any other solid-state amp) due to its being battery powered, and most importantly for someone who wants a tube preamp, it layers space better than tube preamps (you don't want a tube preamp because it is euphonic, but rather, because it expands the soundstage out from the speakers compared to typical solid-state preamps). It neither sounds solid-state nor tubey, but does have the tube preamp traits of a bit of warmth to the midrange and very slightly subdued highs. It can be had used for about $6,000-$6,500.
Unless you are stuck trying to resolve dryness or other problems elsewhere in your system, I think that the preamp is a bad place to add a real coloration to the sound. As the nerve center through which all your music passes, a preamp should be as quiet, as transparent, as resolving and as neutral as possible, or otherwise, you will be putting coloration on top of coloration when you go to add other components (and may end up having to throw the whole soup out).
I only know the SF Line3.
It is a fantastic machine....
I tried many different tubes,Sovtek, Electro Harminix, Jan Philips, RCA, Mullard but the real quality jump has been to replace the Digital Volume Control CS3310 with the new BB PGA2310......a new pre.
I have the 1996 version, I do not know about the last.
Again, judge with yr ears and musical preferences.
the pre is very important but it is a piece of the chain.....
BAT VK51SE doesn't sound "tubey", you can forget that one.
Cary 05 in the mix... stunning.
I dont know about the best but I used both ARC ref 3 and Cary SPL05. I took the ref 3 in as a trade from a customer. It's a great preamp, as a matter of preference, i prefer the SPL05 simply due to a slightly warmer sounding. Ref 3 is dead-on neutral.
The Cary SLP 2002 is a very nice fully balanced tube preamp that isn't as warm as the SLP98 or as neutral as the 6H30 tube preamps such as the calypso, BAT, etc. It is a steal that the used market prices they seem to go for.
I found the SLP 2002 sound to be great. I'd call it slightly coloured. Being 6922 based, there is a lot of tube rolling that can be done to tweak the sound, and it can also take 6CG7's and 6H30's too. A very flexible unit.
FWIW we've built only balanced tube preamps. As far as we can tell, we are the first manufacturer to make fully differential and balanced all-tube preamps (1989). One of the founders of BAT bought one of the first production MP-1s before BAT was created.
I have decided to hold on to both amps I have now, are there balanced preamps that will work with various amps, ss and tube?
Pedrillo, I would expect that any balanced preamp, tube or solid state, should drive any balanced power amp made. I would not worry about that!
A week ago, Joule-Electra announced its new flagship, fully balanced line stage LA-450ME.
Its the balanced tween of LA-300ME which many (I, for example ;--) consider to be the best preamplifier in the world.
Next, "I need balanced inputs and outputs... " does not imply to me that you need to pay for fully balanced preamp or even for preamp with balanced inputs/outputs. With recently introduced spectacular CLEAR XLR/RCA adaptors from Cardas - you can use any single ended preamp you like. They are REALLY clear!!!!!!!!!!!!!!!!
All The Best
My vote is for the Modwright 36.5. If you haven't tried one you are missing out. BAT, CAT, what ever, I've demoed them all in my current set-up and I chose the Modright, it's really an amazing preamp.
Electrostatic I bet you did not try the best VAC or Aesthetix Preamp
My Cary SLP-05 is awesome, preferred to the Modwright 36.5, which is also excellent. I have heard but not owned VAC and it is the best I have ever heard. If I had the cash, that is what I would own.
I recommend the Aesthetix Callisto Signature if you have the rack space. They don't come up used very often though.
The *best* balanced tube preamp is the Vacuum State RTP3D - but it does not have "tuby" colourations - nor does it have SS colourations.
The Rogue Hera or Athena is Superb, the 6h30 is the most linear preamplifier tube out there The Bat sound may be darker is because they use a bunch of Jensen oil caps.Where Rogue uses the Excellent Mundorf Supreme
which are a balanced cap in their own right double wound
to cancel inductance and very musical without going over the Top.The Athena is 95% of the Hera and I have owned the big named products .the parts quality alone in the $5k Athena betters most at more than $10k I know I compared
and next to Audiovalve that TAS magazine gave an award to
the Athena bettered that without much trouble .I owned one for over a year,a very good unit but a little colored
and not as expansive.The Hera brings another 5% to the table .Next time you shop compare what's inside and yes both units have seperate power supplys.