Conrad Johnson CT-6 tube preamplifier

CT6 Composite Triode Preamplifier

Introduced in the internationally acclaimed Anniversary Reference Triode (ART) preamplifier, and recently refined in our current flagship preamplifier, the ACT2, conrad-johnson’s composite triode circuit has provided the benchmark for line-stage preamplifier performance for nearly a decade. Reviewers, other audio professionals, and consumers alike have been impressed by the fine resolution of subtle shadings of dynamics and the solid, stable imaging that this circuit is capable of portraying. We are pleased to announce our most affordable implementation of this circuit in the CT6 line-stage preamplifier.

The composite triode circuit is a conceptually simple design—based on creating a single “super” triode by paralleling sections of individual tubes. In this way, the entire amplification circuit can be reduced to a single active stage, without buffers or feedback. Any active circuit element will color the sound, whether the element is an amplifier or a buffer stage. By designing a line stage consisting of a single composite triode, we are able to reduce the circuit to the absolute minimum of a single active element.

In the CT6, the composite triode is comprised of four paralleled sections of high-transconductance miniature twin-triode tubes. This circuit achieves a sufficiently low output impedance to drive most interconnect/amplifier combinations while eliminating any circuit element that might compromise its sonic purity. To realize the full potential of this amplifier stage, it is powered by a sophisticated discrete voltage regulator designed to completely isolate the audio signal from the power line.

All control functions of the CT6 operate through microprocessor-controlled relays. For the level control, the relays select combinations from a network of precision, low-noise metal foil resistors to effect loudness and balance changes in 100 steps of approximately .7dB per step. All switching and adjustment can be controlled by the unit’s remote control. A Theater Mode, which passes the input signal through at unity gain, makes it simple to incorporate the CT6 into a high quality home theater system without compromising its two-channel performance.

High quality component parts specified for the CT6 have been carefully selected for unrivaled sonic performance and reliability. All capacitors in the audio circuits and related power supplies are polypropylene or polystyrene, and the resistors in these circuits (including the CT6’s level control) are special low inductance, high-precision laser-trimmed metal foil resistors. Switches are sealed relays with gold-plated silver contacts. Even the custom machined input and output connectors have been selected for their sonic excellence.

Through meticulous engineering, careful selection of component parts, and painstaking attention to construction detail, we have created in the CT6 a true reference quality preamplifier at an attractive price. We invite you to arrange an audition with your conrad-johnson dealer to experience for yourself the extraordinary musical accuracy of the conrad-johnson composite triode preamplifiers.

Specifications
Gain: 26 db
Maximum output: 15 vrms
Output impedance: 850 ohms
Distortion: 1,0V Output less than .25 THD
Frequency response: at unity gain: 2 Hz to 10OKhz
Hum and Noise: line-stage 100 dB below 2.5 V
Phase: phase inverting
Tube complement: 4 x 6922
Dimensions: 15.5D x 19W x 3.315H inches
Total weight: 19 lbs.
Aluminum remote control
Info as shown on CJ's website