Teo said:
What means affordable for you ?
Take care that there are lots of manufacturers , the price shouldn't be the only factor .
What speakers do you have ? the valve amps can be found frequently in low power versions , 2x8 W , - 2x20 W , you need there very sensitive speakers , over 92 dB ,probably. These days one guy in greece sell a Cyber 10 Consonance Opera Audio on the auction site -affordable
Another thing with valve amps : they need tube replacement , and then you need to make a bias current adjustment .If the amp doesn't have an external acces to the bias sdjustment screws (like the Cayin ) or an autobias like PrimaLuna (both over my budget for now), there can be a potential electocution hazard when getting inside the amp .If you have a technician who knows about valve amps , you're saved about this lat issue .These things are keeping me away for the moment from the valve amps ,even if I checked myself the web about these .
Some of your concerns are a little over the top.
Whilst it is true that some SET Valve Amps are in the lower power range, some are not. (mine is a 24 Watter) - Besides, I have found that despite low wattage ratings, Valve Amps are powerful beyond their ratings. I have driven Sonus Faber speakers of 'only' 86 dB sensitivity with a 14 Watt Amp to very satisfying levels.
My current Unison Research 24 Watt SET drives my 89 dB Focal 1008Be speakers very well. It's not just about speaker sensitivity, but about how 'easy' to drive they are.
In addition, once you move away from SET Amps, Push-Pull Valve Amps are much more powerful, although arguably not as 'sweet' sounding.
Valves are easy to change and buy, with many sources available online for both new and vintage NOS examples.
Some Valve Amps are self-biasing and others require a few seconds of adjustment from outside the unit.
I have never come across an example where you have to get inside the unit with a screwdriver, as I agree, this would be very dangerous - as it would with any electical device.
There really is little to fear from Valve Amp ownership and they reward you with a sweet, never aggressive, alluring, liquid sound that never becomes tiring.
Most Valve Amps are built like Tanks, are designed to last and most Valve Amp owners take immense care over their equipment, so second-hand equipment is a good buy. They are also relatively easy to repair and maintain vs. SS Amps.
I'm about to acquire a Devialet 200, which is a very different beast to the Unison Research S8 I currently have, but I cannot bear to let the S8 go.....