Valve sound

Tube sound (or valve sound) is the characteristic sound associated with a vacuum tube-based audio amplifier. After introduction of solid state amplifiers, tube sound appeared as the logical complement of transistor sound, which had some negative connotations due to crossover distortion of early transistor amplifiers. The audible significance of tube amplification on audio signals is a subject of continuing debate among audio enthusiasts.

Many electric guitar, electric bass, and keyboard players in several genres also prefer the sound of tube instrument amplifiers or preamplifiers.

Before the commercial introduction of transistors in the 1950s, electronic amplifiers used vacuum tubes (known in Great Britain as "valves"). By the 1960s, solid state (transistorized) amplification had become more common because of its smaller size, lighter weight, lower heat production, and improved reliability. Tube amplifiers have retained a loyal following amongst some audiophiles and musicians. Some tube designs command very high prices, and tube amplifiers have been going through a revival since Chinese and Russian markets have opened to global trade—tube production never went out of vogue in these countries.

Audiophiles disagree on the relative merits of tube vs solid state amplification. Some prefer the sound produced from tube amplifiers on the grounds that it is more natural and satisfying than the sound from transistor amplifiers. Otherwise this preference or difference is far too generalised or even vague without taking amplifier designs into consideration, and there are many. Certainly these audible differences are due to distortion types: harmonic, distribution, level and other factors.

Solid state designs can be manufactured without output transformers and are therefore immune to speaker-dependent impedance mismatches and other transformer effects which alter the system spectral response. On the other hand, flat frequency response does not necessarily mean a good-sounding amplifier. The loudspeaker itself (regardless of price) will likely produce more non-linearity and uneven frequency response than any other part of the system. Typically, in sound reproduction systems, accurate reproduction of the sound of the original recording is the goal; distortion and uneven spectral response is to be avoided.

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