You are probably going to have to make a big jump up in power to drive Gallo 3.1s with tubes. At a 4 ohm impedance and 88db sensitivity they are not an easy load for a tube amp.
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KT88s are generally more reputed to provide rock-type bass and drive than EL34s, but of course other factors in the amp come into play as well, notably the output transformers.
I've been trying to get good bass--weighty, defined, fast, extended--from tube amps for a while. I've found an amp's bass can be improved with a bit of work. Speaker placement and room acoustics count for a lot. Other useful measures include getting the amp down on the floor or near it, on a good platform or stand.
I've used both 100w Manley Snappers and my current ARC VSI60 with 3.1's
They have both sounded great.I f your amp does'nt provide enough bass for you
I'd strongly suggest you pickup a used Gallo sub amp.You can git one for less than $500 nad it will give you all the bass you'll EVER need.Plus you can tune the low end to match your room.I've heard that set up with the Snappers and it is the most dynamic sound I've ever heard.
Assuming this impedance curve is accurate: http://www.hometheaterhifi.com/technical-articles/228-a-secrets-technical-article.html?showall=1 and that your tube amp has a highish output impedance, it's not surprising the bass seems to be lacking. I would guess that you are setting the volume based on the peak in the treble region and thus the bass is way too low.
I did mention that I only listened to the EL34's for about 5 hrs and put the KT88's back in. I did that because when I was auditioning a demo Octave I only had 3 days and 3 sets of tubes (EL34's - KT88's and 6550's). BTW the tubes belong to Dynaudio and my dealer. I Like them all and was doing the demo without my sub to compare just the amps. The EL34's were light on the bass. Now that I bought the Octave I've decided since the 6550's were on order I was going to listen to each set of tubes for at least 2 weeks before rolling to the next set. The KT88's are the ones in now. It also takes a little time to adjust the sub for the different tubes. Tube rolling is fun - at least for me. Oh yeah I have a Rel B3 sub FWIW.
The ability of a tube amp to control woofers on low impedance (4 Ohm) speakers is mostly a function of the quality of its output transformers and size of its power supplies. Beefy power supplies are not at all cheap, and output transformers of the quality required to really do the job are extremely expensive - they only show up in the very best tube amps. There's no solution other than moving to speakers with a much more benign impedance (or switching to a similarly priced solid-state amp, which of course brings its own set of compromises).
The above comment about the Snapper gives me a good example to explain my point about output transformers and power supplies.
The Snapper puts out 100 watts per channel. The CAT JL-1 monoblock tube amps also put out 100 watts per channel. The Snapper, according to its website, has 180 joules of energy storage in its power supply. In contrast, the CAT has 1,000 joules of energy storage. The output transformer alone in each CAT monoblock weighs 55 lbs., the total weight of each monoblock being 192 lbs., with most of the weight being the transformer and power supply. The Snapper weighs 38 lbs., a mere toy by comparison. Top-shelf transformers and power supplies are not only extremely heavy, but are extremely expensive - the CAT amps, for example, retailed for $30,000 ten years ago (the Snapper retails for $4,000). With tube amps, cost and weight are directly correlated and tell you most of what you need to know about quality.
Most tube amps layer space well, tend to be organic-sounding, and have a nice midrange, but with all due respect, they do not, except for the very best ones, control woofers on speakers featuring low impedances in the bass - this is their Achilles heel.
Agree with Rodman. Consider Biamping. I use a tube amp to drive my Coax with a pair of inexpensive SS 300W plate amps driving my bass drivers cut over at around 60z. I love tube amps but very few will provide the level of bass slam or control as SS. I also only biamp the very bottom end. I've tried going higher but you run into coherence problems trying to integrate the tonal characteristics of the multiple amps.