This is a bit off topic but since this is a technology thread, why not.
"Valve music and hifi systems are still made and are the purest sound".
Actually that's a bit of propaganda (if that's the right word) purveyed by the valve amplifier enthusiasts. Surely the best sound is one which exactly replicates the sound source, which simply means achieving minimum distortion. Any solid state amplifier can do that by employing sufficient negative feedback in the design, and in fact it can achieve much lower distortion than a valve amp because more negative feedback can be employed.
If an amplifier is over driven to the point of "clipping, the valve amp does have a slight advantage in that the huge distortion caused by clipping comes on less suddenly as the volume is increased. This is simply because a valve is incapable of accurately following the signal source near the clipping point. A solid state amp on the other hand will accurately follow it right up to the clipping point and then clip hard which generates a lot of harmonics and distortion. Generally though it's easier to build a solid state amp that will deliver much higher power before the onset of clipping.
BTW, it's easy to design a solid state circuit which will mimic the clipping characteristic of a valve, or any other characteristic of a valve for that matter, if that's the sort of sound one wants to hear.
It's nice to see those red heaters glowing though, and feel the warmth. Reminds me of when I started off in electronics .
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