by Sanita Kuyper | Oct 15, 2026 | Blog
NOS, old stock, tested and matched describe different things. A useful valve listing separates manufacturing history, evidence of use, present electrical condition and the quantities being sold. None of these labels, on its own, establishes compatibility with an...
by Sanita Kuyper | Oct 15, 2026 | Blog
A vacuum tube, or thermionic valve, can control an electric current inside an evacuated envelope. In an audio amplifier, a changing input signal controls a larger flow of energy from the amplifier’s power supply. The valve does not create energy: the power...
by Sanita Kuyper | Oct 15, 2026 | Blog
The EL84 is an audio output pentode used in hi-fi and guitar amplifiers. JJ Electronic identifies its version as EL84 / 6BQ5. Use that identification as a starting point for reading the manufacturer’s information, then check the exact valve and amplifier requirements...
by Sanita Kuyper | Oct 15, 2026 | Blog
The Sansui AU-111 rewards careful documentary research. Original advertising, service information and an individual amplifier’s present condition answer different questions. This guide starts with a visually checked original catalogue page and explains what a...
by Sanita Kuyper | Oct 15, 2026 | Blog
The 12AX7/ECC83, 12AT7/ECC81 and 12AU7/ECC82 families contain dual triodes commonly found in audio equipment. Their similar appearance can be misleading. A circuit designed around one family may bias and perform very differently with another. Compare specific...
