Tube amp, more low end

I've just taken my first step into tubes, with a TAD-60. My speakers are Gallo 3.1's. I really like this amp! I can't believe how "real" the music sounds. It really is amazing. The one thing that I do feel is lacking however, is low end "slam", as well as control. I know generally speaking, this is a characteristic of tubes. But I'm wondering I there's an affordable tube amp ($1500-$2000), that will offer the magic of the TAD, but with some more low end control?

Also, the TAD is currently running el34's. Would switching to kt88's make much of a difference? If I need to spend $300 or $400 on better tubes, I'd just as soon upgrade the amp.

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.
I just got an Octave V70Se with kt88's and there is is a ton of bass. Almost too much. I have some EL34's but only listened for about 5 hrs and put the kt88's back in. I'm driving Dynaudio C1's at 85db - 4ohm. Great match up
If you search the threads, you will find there is a fair amount of discussion about Gallo 3.1 speakers and tube amplification.
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.
you could just get a good subwoofer. I don't think the switch to a different tube type will give you what you're looking for.
With the Gallo sub amp it will be like having stereo sub woofers,and they blend in perfectly wth the rest of the speakers
Assuming this impedance curve is accurate: 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 definetly would keep the EL34's!
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 3.1s are not
'hard to drive" I've had a pair,
As for good output transformers and poer supplies,the Manley snappers at $4000 retail,do the job extreamly well.And they feature EL34's
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.
Since you like the sound of the amp you have; you might consider adding the Gallo TR-2 Subwoofer to the mix. You would essentially be bi-amping, with a 250 Watt amp, powering the bass. Much more "live" sounding bottom, than any tubes, or tubed amp(at an equivalent price), would provide.
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.
Or as I said add the Gallo 200wpc sub amp
Allot of guitar amps, like Marshall, use EL34s, so their ability to rock should be of little question.
Producing the sound of one electric guitar, takes much less juice than reproducing the sound of a band/orchestra, and all it's bottom end.
Just to update what I'm doing. I just bought a Gallo sub amp, so I'll give that a try and see what I think. If I can get the low end that I've heard out of these speakers with my ss amp and the realism that I'm getting with the TAD 60, I will be a happy guy.
Good move.

I think this will give you the right amplification combo for best results overall!
I think you made the right move.
Be patient my friends a top engineer and he took weeks to get his dialed in,and it sounds amazing.
I have had better bass response using a Seimens 6CA7 tube than an EL34. Does not sound as good in the midrange though is my system.