More generally, I don't know any technical reason (*) to use valves except in the output stages of direct-drive amplifiers for electrostatic loudspeakers, in guitar amplifiers and in equipment that has to survive large electromagnetic pulses. People like to use them anyway.
(*): Semiconductors generally have more curved voltage-to-current characteristics than valves, but you can design around that disadvantage.
(*): Semiconductors generally have more curved voltage-to-current characteristics than valves, but you can design around that disadvantage.
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One could argue that electron valves' ability to run very hot without the heroic measures needed to keep semi-cons alive is a compelling virtue. Class A operation ensures a monotonic curve of distortion with signal level which is sacrified, to some greater or lesser extent, with any efficient modern mode. Heat isn't a bug; it's a feature!
All good fortune,
Chris
All good fortune,
Chris
One reason why I like valves is the ability to create a circuit with very few components, things can be very simple. For a complex and confusing set of factors every component, wire and switch has a small and sometimes not so small influence on the sound quality (my objective). With a simple circuit you can change something as apparently benign as a resistor and see a change (better or worse) result in the sound quality. So you can evolve and create the sound you are looking for. With solid-state things are too complicated to follow the same path to improvement as easily; you generally have to swap the whole unit, and keep ying/yanging to a preferred sound.
Bypassing the question of whether or not things like resistors and capacitors can be audible or not, a shorter signal path does minimize distortion order growth over multiple stages, and devices with lower intrinsic distortion allow fewer stages for the same closed loop gain all else equal, but*
Everything recorded has been through an amazing number of stages, an amazing number of resistors and capacitors and op-amps, at least one each A/D and D/A conversion, some microphones and some loudspeakers in some room, and some human discretion about how the recording "should" sound, but*
The classical argument is that the output of an amplifier should be a scaled replica of its input, and that residual defects should first be minimized in rank of audibility, secondarily by "musicality", meaning forgivability within an undefined musical context. This secondary definition is often taken to the extreme of considering an amplifier to be a tone shaping device, like a loudspeaker, but*
*but What matters to some folk is just that valve amplifiers are somehow "organic" enough to understand without knowing quantum mechanics, and forgiving enough (safety precautions first!) to feel comfortable to experiment with, and rewarding enough even with flawed early efforts, to keep interest alive. This has its own virtues.
For me, the ability to still see the work unaided and to work with shakier older hands allows me to continue in my favorite field. Hate to use the term "organic" but it somehow applies. Old tech from a classical world mindset.
All good fortune,
Chris
Everything recorded has been through an amazing number of stages, an amazing number of resistors and capacitors and op-amps, at least one each A/D and D/A conversion, some microphones and some loudspeakers in some room, and some human discretion about how the recording "should" sound, but*
The classical argument is that the output of an amplifier should be a scaled replica of its input, and that residual defects should first be minimized in rank of audibility, secondarily by "musicality", meaning forgivability within an undefined musical context. This secondary definition is often taken to the extreme of considering an amplifier to be a tone shaping device, like a loudspeaker, but*
*but What matters to some folk is just that valve amplifiers are somehow "organic" enough to understand without knowing quantum mechanics, and forgiving enough (safety precautions first!) to feel comfortable to experiment with, and rewarding enough even with flawed early efforts, to keep interest alive. This has its own virtues.
For me, the ability to still see the work unaided and to work with shakier older hands allows me to continue in my favorite field. Hate to use the term "organic" but it somehow applies. Old tech from a classical world mindset.
All good fortune,
Chris