Type Tube Preamplifier
Response 20-20kHz (+0.5 -0.5dB)
Noise and hum -85dB high level
Output rated 2.5v, 10v max
Input sensitivity and impedance aux 0.25V at 250k, phono 2mV at 47k
Center channel out 1.0v with control (L+R)
Individual tone controls bass and treble +20dB to -20dB
Rumble filter 50Hz at 12dB/octave
HF filter 5kHz at 12dB/octave
Low frequency trim controls 6dB of boost below 100Hz
Voltage gain 20dB aux, 62dB phono
Tube Complement 6x 12AX7
Cabinet L11, also fits L12, L52, and L62
Dimensions 5.44"H x 16"W x 13"D
Weight 16 lbs.
The C22 Stereophonic Preamplifier combines excellence in performance with ease of operation. The most often used controls have large diameter knobs. A new type of rocker switch is used for the controls with simple on-off functions. The C22 has an illuminated front panel with a light intensity switch to provide convenient reading under low-level lighting conditions. The Mode and Input Selector switch positions are also illuminated. The C22 circuit consists of 3 amplifier sections in duplicate for the left and right stereo channels together with a common power supply. The first amplifier section is the input preamplifier used to amplify and equalize signals from phonograph pickups, microphones or tape heads. Skillful circuit layout, proper grounding, and adequate shielding reduce the hum so low it is virtually unmeasurable. Extreme care in manufacturing combined with low noise tubes, high specific resistivity circuit boards, metal film and wire wound resistors achieves new low in residual noise.The second amplifier section follows the main volume control, making it impossible to overload the high level input circuits or any following circuits. The same design techniques as used in the preamplifier section assure low noise and hum. The Bass and Treble feedback-type tone controls operate in connection with this amplifier section. The controls are switch-type with approximately 4 db change per step. Exceedingly low distortion and precise control of frequency response contours are assured using this arrangement. The third section is the cathode follower output. The sharp cutoff (18 db per octave) Rumble and HF (high frequency) filters are associated with this section. Output level controls are located at the inputs of the cathode followers to allow simple balance of the entire system. These controls are located on top of the C22, behind the front panel, conveniently accessible by releasing the panloc buttons and sliding the C22 out to the adjust position.