Santa Barbara-based Seymour Duncan released their third stompbox, the SFX-03 Twin Tube Classic™. The Twin Tube Classic is a two-channel guitar preamp that uses a duet of subminiature 6021 dual-triode vacuum tubes and is voiced to evoke the classic sounds that define rock and roll. The new-old-stock, USA-made Phillips Sylvania® 6021s represent the pinnacle of tube technology. They were designed and manufactured to meet the U.S. Government's MIL-E-1 spec for reliability under conditions of severe shock, vibration, and temperature. They provide extremely long service life and exhibit virtually no tendency toward microphonics.
High-quality vacuum tubes are only part of the key to a great-sounding tube preamp. Too often, inexpensive tube gear runs in "starved plate mode," where the tubes function like clipping diodes and do not actually amplify. The Twin Tube Classic employs a fully encapsulated, toroidal transformer to achieve the high plate voltage required for true tube amplification. The 100% vacuum tube signal path with a high-voltage power supply allows the tubes to operate at their fullest potential. The result is maximum dynamic range, the most gain, the smoothest tone, and the low-order harmonics one expects from a great tube preamp.
The Twin Tube Classic is a two-channel device, with a volume and gain control for each channel. It effectively provides three channels to a single-channel amp: Rhythm, Lead, and bypass. Voiced for classic rock tones, the Rhythm channel goes from a hint-of-grit to moderate crunch and the Lead channel goes from chunky overdrive to thick distortion. The Twin Tube Classic also features true bypass with gold relays, up to 90 dB of gain, a silent switching circuit designed to eliminate pops and clicks when changing channels, and a heavy-duty chassis with a candy copper paint job and stylish "chicken head" knobs. A 16-volt AC transformer is also included.