ECC32, 6SN7GT, 6SN7, 13D2, B65, CV181, CV1988, 13D2, SMALL SIGNAL, OCTAL

The 6SN7GT double triode valve is electrically equal to a pair of the 6J5 triodes within a single envelope. The construction uses a glass pinch, and the two separate electrode cages are visible through the envelope. The wide glass tube envelope is 27 mm in diameter and excluding the IO base pin length, stands 63 mm high. Type 6SN7GT was first marketed in 1940.

The B65 Marconi-Osram variant with its distinctive metal clad octal base was first marketed in 1948.

The Mullard ECC32 variant is perhaps the first iteration of the type, first marketed in late 1939, as the valve of choice for low noise audio applications. Mullard describe the ECC32 as a double triode with separate cathodes for use as a paraphrase AF amplifier and in phase inverters. The electrode assembly although smaller than other double triodes of the period have supreme rigidity due to the glass pinch mounting mode. The curved anodes do much to increase surface area allowing impressive anode dissipation whilst enhancing rigidity and the sonic purity this can provide.

This Octal triode is favoured for many guitar and classic valve amplifiers, the most renowned being the Leak TL12 0.1 of 1946/7, however, it is surprising which other well regarded and modern exotica also demands fine devices of this type.