Description
The RCA 12B4A is a NOS medium-mu triode manufactured by RCA in the USA. It uses the B9A noval 9-pin base and was designed for use as a series regulator in power supplies and as a driver valve in audio amplifiers.
The 12B4A has found a following among audio DIY builders as a driver valve and in some headphone amplifier designs, where its combination of moderate gain and good current capacity is useful. RCA’s quality control and NOS condition make these examples particularly attractive. NOS, made in USA.
Noval 9-pin base. NOS, made in USA by RCA. A single valve is supplied.
