General Information
The Twin Tube Classic is designed for years of solid performance. One of the secrets is the duet of type 6021 tubes. These sub-miniature dual triodes represent the pinnacle of tube technology advancement. The 6021s were designed and manufactured to meet the MIL-E-1 spec for reliability under conditions of severe shock, vibration and temperature. They provide extremely long service life with virtually no tendency towards microphonics (see USA Department of Defense Standards, Test Methods for Electron Tubes). Also, unlike some “tube” stomp boxes that only use the tubes as a clipping diode, the Twin Tube Classic employs a 100% vacuum tube signal path with a high voltage power supply. This allows the tubes to operate to their fullest potential and provides the most gain and the smoothest tone. The result is the classic tube sound, smooth distortion, and low order harmonics you expect from a great tube preamp.
Tube Life
The 6021 tubes will typically last many times longer than even the best 12AX7s. For most Twin Tube Classic owners, this means youʼll never have to change your tubes. However, nothing lasts forever. Should you find your Twin Tube Classic in need of new tubes (e.g., exhibiting erratically fluctuating signal levels, spurious increases in noise, sputtering, low-level whistling, extreme loss in frequency response), contact Seymour Duncan or your favorite authorized Seymour Duncan dealer for your options. Do not try changing the tubes yourself. Changing tubes on the Twin Tube Classic is more complicated than plugging pins into a socket and could be dangerous. Make sure a professional does the work.
Two channels means versatility. When coupled with (true) bypass, this effectively provides three channels: Rhythm, Lead and bypass. Separate gain and volume controls allow Lead and Rhythm Channel levels to be independently set. The meticulous internal layout minimizes cross coupling and unwanted circuit interactions that can be a major problem in high-gain / high-impedance vacuum tube circuits.
