How to determine Preamp "Power"? VTL 5.5 vs BAT SE

I would like to get a tube pre and amp that has a low end on the heftier side. I think I understand that a tube amp with KT88s will have a heftier bottom end than that of an EL34 system (right?). So I have begun looking at a tube pre that will support the bottom end of a KT88 amp.
VTL has a reputation for a strong bottom end. The VTL 5.5 LS pre uses these tubes: 2 x 12AX7, 4 x 12AT7. The BAT 3iX SE (for example) uses 2 6H30 and 2 6V6 tubes. I have read that the 6H30 tubes will give more power at the frequency extremes, eg bottom end than EL34 and even KT88 (yes? no?). If so, how would the pre "power" of the VTL 5.5 compare to the BAT SE in terms of bottom end heft? Or, am i looking at this all wrong? (tube newbie). Thanks!
Hello, have you considered the NAT Audio tube preamps? In particular, the Symmetrical model is a worthy contender.

The Symmetrical uses 12 tubes (each half of the tube is used fully). Incrediblly clean, dynamic and very natural sounding.

We import the line so naturally I am biased towards them but, you really should take a look at their website at this link:

Good Luck
To Musical sound:
I can't understand why when somebody ask suggestion about some products there is always somebody suggesting something else.
Are you promoting the stuff you sell or are you giving an answer (and I don't think so).
Just my humble opinion.

To 1graber2: I don't think that comparing 2 preamp or power amp simply on the tubes they use is useful. The only way to know how they sound is to listen, possibly into your system.
I have had a VTL 5.5 for a number of years, previouly had a 2.5 for a really long time, but have no experience with BAT, other than listening to friend's systems.

It may just be me, but I tube roll 12ax7's a lot in my 5.5 and can really notice changes in the mids/highs, but not so much down below 50-60Hz to me. I have noticed the lows change more when changing power cords and IC's between the 5.5 and my SS amp(McCormack DNA-500) than tubes, for me. The lows can get really dark and less tight(is there such a thing). It could be I'm tone deaf down low too? I currently am running Mullard 12AX7's and like them a lot. Why? They seem to make the mid's/high's of the acoustic and classic rock and jazz I listen to really sing. Sheryl Crow, Bonnie Raitt, Joni Mitchell and Diana Krall seem magical with Mullards and RCA clear tops, less so with Sovteks', JJ's and other Soviet stuff in mine. Changing the 12AT7's on the other hand does nothing that I can hear, either up high or down low. It could just be me too.

I hope some of that helps a little for you. Good luck and enjoy. I know I enjoy the VTL sound, but that's what I've purchased after listening, vice other good stuff, which there's plenty of.

Either way, enjoy the music and don't worry about equipment so much. Life is too short and there's too much music to listen to and wine to drink while doing it to waste too much time chasing hardware like some folks. The music is what we're after, right????
You might also look at the ARC LS26.
Musical_sounds, with all due respect, these forums are NOT for shilling. If you want advertising space, please pay for it like other dealers.

1graber2, I have owned several BAT preamps (VK-31SE/ VK-50SE/ VK-51SE) and have auditioned a couple others in my home (VK-3iXSE, VK-32SE). I also have owned many other preamps including a VTL, though to be fair, it was not a late model VTL product (TL-5).
The bottom line is I have never heard any preamp with more power in the bass than BAT preamps, and that includes SS preamps from Krell, Levinson, Threshold, etc.
I don't believe that the tubes being used have as much to do with the bass as the huge power supply BAT tends to use. The six-pack caps, the Super-Paks, etc. BAT preamps have beefier power supplies than many amplifiers out there.

That being said, the best preamp I have ever owned was a ARC Ref 3. Though it's bass was not as powerful as the BAT's bass is not my top priority, and the ARC was clearly better in several other areas.

To my understanding as explained to me by a tech from Conrad Johnson: EL34's are best for monitors.
Are your speakers monitors or floorstanders?
IMHO: I would go with the BAT SE for the power amp & the dual chassis VAC Ren. Sig. Mk. II pre amp (the best pre I've ever owned).
Best regards
The innards of the power amp such as capacitors etc, is what is going to determine the bass output capabilities, not the tube type. There are plenty of KT88 amps with minimal low frequency slam.
THanks for all the input. Yes, I was afraid I was oversimplifying this comparison of pre output power based on tube types only. I actually have the BAT 300X SE hybrid integrated amp (150Watts) running a pair of Dali Helicon 400s. Im pretty happy with it for much of my music, but certainly not all, as I listen to a broad variety: the bottom end just gets a soft at times. I like BATs version of "musicality" and the fluidity it offers. I'm not searching for the "perfect" system, but want to try to move toward a tube pre/ SS amp to listen to most of my music. I plan to go to separates at some point, so am considering the VTL and BAT. I plan to try a Simaudio Moon W-3 (125 Watts +) or W-5 (190 Watts+) as my SS amp. The thing is that my listening room/bed room is only 12X15. The Dali's are almost too big already, so am shooting for a powerful amp to tighten the bass and achieve good sound at lower volumes.
Any feedback would be helpful.
Instead of changing equipment, consider adding a powered subwoofer to your setup?
have not owned BAT or VTL, but have owned some ARC and SF L3SE in the past. SF L3SE, despite its large power supply, does not offer as much bass weight as other reference class pre amp though the quality of bass is top notch.

if what you are after is tight and deep bass, check out Einstein pre amp. another pre amp to consider is EAR top model with transformer coupled output stage.
I have owned both, BAT{vk-31se}, and VTL 5.5,in my opinion the VTL,has better tonality, very sweet sounding, not as dinamic as the BAT,but the bass and mid's of VTL are top notch,I'find BAT, sounds analitical and dry not as organic and fluid as the VTL,just need a good PC,like synergistic master coupler and you be in heaven, had to spend two times the price of VTL to upgrade, just my opinion.