Tubes vs Solid State

As Ralph (I am assuming it was Ralph for Atmasphere) said, it is all in the matching- I have used tube amps since the very early 70's and have used many ARC products during that time. ( I currently use very low powered SET tube amps by Lamm, but while the amp i have is wonderful, it is not suited for all speakers). I tend to like smaller rather than bigger tube amps, in part due to the size, complexity, heat, retubing cost, etc. I'm sure that big ARC amp would be killer in the right application.

As far as tube availability goes, I buy most of my tubes from vendors over the phone/Internet, so location is not a big deal. (I don't even know of a brick and mortar store I could go to, even in NYC, to buy a tube these days).
If you are open to experimentation, and want to play around with tubes, why not experiment with a tube preamp to get started? And you could have some fun 'rolling' tubes and getting to see how different tubes affect the sound. (Just be aware, those little preamp tubes can cost much more than big power tubes, if you are buying 'new old stock' vintage tubes).
Tubes make real magic with electrostatic speakers: Quads, Martin Logans, etc. If you were willing to buy a decent pair of electrostats and a decent tube power amp, you could quickly see what tubes can do and how they differ in sound from SS. Atmasphere's amps and a good pair of electrostats would be killer. (I am currently using horns, but have two pairs of Quads, a 63 and a 57, and those are all marvelous on modest e.g. 60 watts or less tube amps- in fact i have the original Quad amps that match my Quad 57's and with 12 or 14 watts, they are a perfect match).
Today, there are some marvelous solid state amps, at least toward the top of the food chain. So, despite my long history with tube amps and preamps, I'm not advocating a 'tube is better than ss' view; again, it has to do with matching, to the speakers, to the preamp (and the source components) and ultimately, to your ears.

For movies plus music I would stay with SS. The big AR 600s would likely be seductive for acoustical tracks but may(??) lack the immediacy of SS on movies and driving rock. As others have stated tubes can be quite a treat but do require maintenance and can create a lot of heat. For your speakers and application SS would be my choice, IMO my 800ds are fantastic with big SS monos with all genres.

I have a set of B&W 802Ds. The impedance curve is rediculous, dropping to 3 ohms in mid base. You need high power SS amp to drive these. But if you like the tube sound, there's a good compromise. The Cary SA-500.1 monoblock can drive the 802's with ease and still have that airy top end tube sound. I have a pair of these and they are fantastic, huge bass extension with great mids and highs. I'm using the Cary SLP-05 to drive the amps. But the preamp needs some good NOS sweet or soft tubes since the diamond tweeters are so strong.

Maybe a hybrid power amp would work well;being able to roll different tubes for personal taste and also have the power required to drive the load the B&w's present;moscode
401hr,402au (moscode has in home auditioning) and there are other manufacturers of hybrids as well.

There has been the question of why there is 4 ohms. The answer is that it makes it easier to make power with transistor amps.

But making power is not by any stretch the same as making the best sound for a given amp. You can look at the specs of any amplifier made and one thing is made clear over and over- with lower impedances the amp will make more distortion.

There is a device called the ZERO which allows you to drive a 4 ohm load, while the amp is loaded at 16 ohms. Even people with transistor amps and class D have reported that the the system sounds better when using the ZEROs rather than driving directly, even if the amp has no apparent problem driving the lower impedance.

The reason why 4 ohms is problematic is several. For conventional transistors, there is a non-linear capacitance exists as part of the junction of nearly any semiconductor. The capacitance is magnified by increased current through the device. This causes increased odd-ordered harmonics; IOW if you put the amp on a high impedance load, it will have less of these odd orders and so will sound smoother.

Output transformers of conventional tube amps will loose as much as an octave of low frequency bandwidth when driving 4 ohms as opposed to 8 or 16 ohms. The transformer will also be less efficient and heat up more and there will be higher distortion (open loop).

Finally, speaker cables become critical- you should not expect to run any speaker cable over about 2 meters with 4 ohms speakers if you want the best response. In addition, the gauge becomes important, a few hundredths of an ohm can have surprising effects on the damping factor.

Four ohms became more popular when the transistor made its way into hifi. It is a way of possibly getting more power out of the amp. Only a few years earlier when tubes were the only game in town, speaker efficiency was pretty important (which is why there were so many horn systems from the 50s and 60s). Transistor power was cheaper to make, and speaker manufacturers realized that if they made the speakers less efficient, they were a lot cheaper to make too. Four ohms was a way of getting back some of the 'efficiency' but of course what we are really talking about is 'sensitivity'! If you don't know the difference, go back and look at the link I initially posted in this thread.

IOW follow the dollars- its cheaper to make less efficient speakers so four ohms 'helps' with 'drivability'.

But in the world of high end audio there really is no argument for lower impedance, as all amplifiers known do not sound as good on the lower impedances, increased power or not. In high end audio, its about sound quality as opposed to sound pressure, so the additional 3 db you get by doubling power from 8 ohms down to 4 isn't a big deal.

Now there are a lot of software programs for designing speakers that say if you put two drivers in parallel, you double the efficiency (which is part of why you see such loads show up so often). This is incorrect- you double the *sensitivity*. IOW add 3 db but that 3 db comes from the transistor amp, not the speaker!

There is also the myth of 'control' that the amp has over the speaker. Any amplifier will have more control over 2 drivers in series than in parallel, yet you will see many who insist its the other way around. But if you look at it from a damping factor perspective, an amp that drives a 4 ohm load with a 20:1 damping factor will have an 80:1 damping factor on the same drivers in series...