Tube amps under $7500

My personal favorite is Sophia Electric...a number of excellent sounding amplifiers and what you hope for when you go to tube amplification.....

So many more fine tube amps out there than I ever dreamed existed. But in order to get their benefit, I would need to change speakers and add subwoofers (which don't augment, but actually constrain, the performance of Legacys in any configuration possible for my space). These are -6dB at 22Hz. Many superb speakers hit -6dB at 30Hz or above. It took the contributions on this thread to make me recall why I had gone with Legacys in the first place. Fully enclosed, can be placed near front wall. High frequency hearing loss and compensatory bias toward low bass articulation. It's a long list.

re: "For pairing experimentally with various tube and SS preamps."

Some members may be running right past this requirement in your original post.

If I were in your shoes [IF  this is truly a requirement] I’d probably be looking at manufactures also offering a nice matching (primary) preamplifier that you’ll enjoy along with your selected amplifier(s). Matching up the right preamp matters too, many will chime in here or just look at old threads on this topic.  Next is your balanced connection requirement, which limits the field as others have already stated. With your stated $7500 budget limit set for the amp(s), does this change overall spend equation some if the budget for the [balanced] preamplifier is also brought into discussion now too?

Mixing and Matching:

Like others here, I too pair up my SS and tube preamps with SS and tube amps. Even with good-full Class A 50w SS, in the end solid state sounds like solid state, and tube sounds like tube. Sure, mixing types of each produces a nice hybrid sound. @hickamore gotta ask, can you see yourself also drilling in a little more on your choice of preamplifiers now too?

While looking at amplifiers, maybe take some time and focus to look at good preamplifiers, before selecting your primary tube amplifier. In my systems, the preamplifier choice has a notable impact on the result and enjoyment. One thing is for sure in my system, when I connect my best tube preamplifier into the mix, something really nice occurs about the sound. Matching with the amp matters. My .02 cents fwiw.

Ask:

Do you also have a sense as to what manufacturer’s PREAMPLIFER and model you might choose as your primary preamp for your system?

@decooney Much appreciate your thorough review of the entire course of discussion. I will try to clarify my position on each issue.

1) Why focus solely on the amp? Because mine is beyond its ten-year warranty period, long out of production, and frankly losing its grip on challenging material. So, what better time to reconsider tubes before committing to a costly new decade-long companion? Especially considering I changed speakers during that period.

2) Why ignore preamps? Because in my experience, it's the preamp that establishes the sonic signature, but you can't work on that until your output chain (amps/speakers) has become a constant in the equation. A prerequisite, if you will. I am ALWAYS looking at preamps and need no help on that question. Being stable at that position in the lineup at present, I must focus first on the amp, then the DAC, before playing with preamps, which for me is where the fun lies.

3) Why the balanced specification? Because this helps to limit an otherwise boundless field of choice. (Same with my requisite of silver, or at least non-black, finish). In my setup, balanced operation helped with impedance matching, gain, and long-ish cable runs. Not to mention manufacturer recommendations. So I became a "balanced guy," and if that seems arbitrary in one sense, it is surely not irrational in any sense.

4) Why the default position of tube pre + SS amp? Because I can't live without a tube pre (though I also have a fully balanced SS on hand), while my Legacy speakers quite likely can't live with a tube amp, as I have just learned.* Frankly, I am also lazy. Even if the tube amp is self-biasing, amps sit down in a dark corner of a dark room near the floor. Some use three different tube types, requiring matching spares of each on hand. I'm just not the born gearhead obsessive that so many in here are. (No knock on them -- I learn a great deal from the experts, the wizards, just reading their hugely informative posts in here).  

Hope this clarifies where I am coming from. 
*From two different Legacy dealers, one in LA and another in Minneapolis, both of whom also sell plenty of tube gear. ("High current, and running deep in Class A to emulate tube sound").

Maybe consider a 6sn7 preamp and 250 watt amp that doubles in power. With $7500 you could find a Don Sachs, Supratec type preamp and an older Pass Labs, CJ or others. I tried BAT, ARC, Rogue they were nice but felt they were more in solid state territory, in case that’s what you are trying to avoid. Just make sure impedance matches.

i had a Don Sachs pre and amp very natural with a great layered sound stage, the preamp matched with solid state very well. 

@paulcreed You are right in my wheelhouse. Appreciate the reassurance.

@hickamore fwiw thought I’d mention that I’m doing what @paulcreed recommended. Currently running a different brand 6SN7 tube preamplifier with a full Class-A 50w Pass Forte’ 3/1A (upgraded) solid state amplifier as my secondary system. Speakers are 92.5db efficiency. Funny thing is I’ve kept this tube pre and ss amp combo in place past six months giving my tube amps a long rest. Or, that’s my excuse, and yet I’ve enjoyed listening to it for while now. Offers a nice hybrid sound and while biased in full Class-A, it manages to hold my attention better than expected. These very long rotations truly allow me to appreciate differences.

@decooney As should be obvious, your secondary system would be my primary. Just one question: what is the O/I impedance ratio of your 6SN7 tube preamp to Pass Forté (as upgraded)? Depending on preamp, with amp change I would be moving from 1:110 down to 1:16 or 1:25.

@hickamore estimated 1:106 as per spec in its prior and upgraded form following your math ratio approach. While I'm not near the gear or have a means to measure anything, its a guess at best. 

Maybe I should restate this. Whatever is in play for six months (like it is now), is my primary system, LOL.  However, when push comes to shove and I begin parting with my two systems for room and system changes, it's going to be really tough to let go of either of the two sets of amplifiers. Maybe both of them are primary whenever they are in play. :)  Each offers its own enjoyment in different ways.