Find yourself a used Audio Research amp and preamp in your price range, 60 watts per channel or more with Audioquest cables. It's the perfect match with your older 2Cs.
Forget about 300Bs and any other low powered amps. They will not cut it in the bass on those speakers.
What tubes did ARC usually use? Just curious.
The Audio Research amplifiers that are the same vintage as your 2Cs used 6550 output tubes. If you have a budget of $2,000-$2,500 you can pick up an ARC Classic 60 and SP-14 preamp and you will have a first class system that is a perfect match. Add a Vandersteen 2W subwoofer and you will be hard-pressed to find a better sounding system regardless of price.
The ARC is not in my opinion very sweet in the treble. It is by their own account very "High Definition". The sweetest tubes of their own nature are the 6L6, the 300B, the EL-34 and finally the 6550s. I find KT-88s to be somewhat less harsh in any given system than the 6550s. The system however will ultimately decide how the tube sounds. The Vandys naturally have a sweet treble and I would be surprised if anything other than certain crappy tubes of any type would produce strident highs. I happen to be a big fan of the current production Gold Lion tubes. But the KT-88 is a more potent tube in general than an EJ-34 which was really your question. My answer go for a top quality EL-34. Gortunately there are many from reasonable to ridiculously expensive it is your choice. I used to prefer the JJ E34L blue glass but have heard good thing about the reissue Mullards and others.
You may also want to consider the Genelex KT-77's which is an EL-34 variant . I use the Genelex KT-88's in my Cary SLI-80F1 and like them very much as they produce solid bass with extended highs and a nice mid-range basically an all around nice tube.
Robertsong, If you plan on using the older 2Cs stick with ARC. That is all Richard Vandersteen used at the shows back then and Audioquest used Vandersteen speakers to evaluate their cables. You can't go wrong.
I agree with Czbbcl on the Genelex Gold Lion KT-77. I have a Music Reference RM-9 MKII. I started with Shuguang EL34 for about 6 years, then went to Shuguang KT88s for almost a decade and recently re-tubed with the Golden Lion KT-77. I always liked the EL34 midrange and treble, but when I went to the KT88s I was immediately seduced by the tighter bass and slam. I stayed with them, trying to convince myself that I liked the KT88s better. One of my KT88s recently shorted so I pulled the old and tired original Shuguang EL34s out and re-tubed. With the EL34s, I remembered what I was missing with the KT88s. Time to re-tube so I gave a call to RamLabs and after some discussion they recommended the Genelex Gold Lion KT-77, it has the magic of the EL34, with the tighter bass and slam of the KT88s. They were correct, in my system, the KT-77 is the best of both worlds. Caveat, my comparison is with Shuguang EL-34 and KT99, compared to Genelex KT77. I have not heard the Genelex Gold Lion EL-34 or KT88 in my system. Who knows, I might be equally blown away by those
"If you plan on using the older 2Cs stick with ARC."
I'm not sure how long I'll be sticking with the 2C's. I want to get a good amp now, and maybe new speakers later. I know for a fact that there are many good tube amps out there that work great with the 2C's. I'll definitely add ARC to the list though.
"I have only heard the EL34's in action so far."
"I know for a fact that there are many good tube amps out there that work great with the 2C's."
I have used both types in my Quicksilver amps. The KT88 has a bigger brighter sound. The EL34 has a more laid back sound. With Vandersteens (a laid back sounding speaker)I would go with a KT88 tube amp.
I'm not clear if you're asking the question so that you can narrow your choice of amps but it isn't necessary to make the decision between EL34 and KT88 power tubes in advance. Quite a few excellent integrateds will let you use both those tubes, and many others. The Primaluna Dialogue is one, as is the Cary Sli-80.
If you're fairly new to tubes that's a really nice feature. Being able to change tube types lets you more easily match the sound to your other equipment and discover the sound you prefer. And tube rolling is fun.
The first tube amp I bought came with KT88, EL34 and KT66 tubes. Ultimately I listened primarily to 5881s and KT77s but someone else, with a different source, speakers and taste in music, would likely have had a different preference.
I am a big fan of the EL-34 tube, I find it combines a lot of the warmth of SET tubes with more power levels and in the right implementation can sound fantastic. I have a pp 17 watt EL-34 amp and I could not be happier. This was after running through 300B's, and 6550's in various amps. I have not checked out KT-77's but may have to soon. Another bonus of EL-34's is they can be super cheap to replace, one of the reasons I opted out of 300B's was high tube replacement costs.
I have SED EL34's - 6550's and KT88's. The EL34's have that great mid range magic that is hard to beat but lacks lows - highs and power. The KT88 has a world more bass and a little more in the highs. The 6550 on the other hand is extremely linear from top to bottom. Again those are all SED's. My Tung Sol 6550 solid black and grey plates have that EL34 mid range with the lows and power but still a little rolled off in the highs. Now unlike the SED KT88 the EAT - Gec and Tesla KT88 have the best highs with a good mid range and great lows. Except for the EAT the Gec and Tesla are expensive vintage tubes. EAT is currently being produced and expensive. The EAT were/are my favorites. I mean they are my favorite in sound but not reliability.
All that being said you need to get the amp first and try different tubes. I found with my Octave V70SE integrated the input tube can alter the sound the most.
Consider the quicksilver silver 88 or silver mono...simply magic with Vandys. The m60 quicksilvdr gives you el34 or kt88 options.
I am running Quicksilver mid monos with kt88s, the added power of the kt88s were a big step up from the stock el34s. Mostly in dynamics.