conrad-johnson Premier 140 Vacuum Tube Power Amplifier
The Premier series of conrad-johnson products are precision music reproduction instruments designed to meet the needs of audio industry professionals and other audiophiles who require near perfection from their reference systems.
The latest in the highly regarded Premier series of vacuum-tube power amplifiers, the Premier 140 is the proverbial iron hand in a velvet glove – capturing delicate textures and subtle nuances while demonstrating muscular power, authority and control.
The Premier 140 audio circuit consists of three stages.
The input signal is amplified by a single-ended triode amplifier designed for wide band-width. The signal is then direct coupled to a cathode coupled phase-inverter. This high current, triode phase-inverter stage provides a balanced, low impedance drive to the output stage. Output power is developed by two pairs of 6550s per channel, chosen for their excellent sonic character, high power, and reliability. The output tubes are operated in ultralinear configuration which offers a desirable combination of high power and low distortion. Massive output transformers with intricately interleaved windings afford extended bandpass and high phase linearity. A small amount (about 12 dB) of loop negative feedback reduces distortion and achieves a sufficiently high damping factor to control reactive loudspeaker systems.
Power supply design is every bit as critical to the performance of an audio component as the audio circuit itself.
In the Premier 140, separate, low impedance, discrete dc power supply regulators are provided for the input and phase-inverter stages, preventing the output stage from modulating these stages through the power supply The main power supply reservoir uses a bank of massive custom polypropylene capacitors. No electrolytic capacitors are used in any of these power supplies.
The Premier amplifiers require no complicated adjustments or specialized equipment to maintain. To assure continued peak performance, the owner need only make a simple bias adjustment when new tubes are installed. Built in LED bias indicators allow the user to make this adjustment using only the supplied screwdriver.
At conrad-johnson we are keenly aware that component parts contribute importantly to the sonic performance of any circuit design.
The Premier 140 amplifier maintains the exacting quality standards for which conrad-johnson is internationally known. Resistors are precision tin-oxide deposited on glass and bulk metal foil. All audio-circuit capacitors are polystyrene, while the power supplies use large value polypropylene in parallel with polystyrene capacitors. There are no electrolytic capacitors in the audio circuits or in the related power supplies. Proprietary wide-bandwidth output transformers contribute to excellent high frequency performance. Even the machined gold plated OFC connectors and the internal wiring have been carefully selected for optimal sonic performance. Attention to details of this kind enable us to extract the full potential from our circuit designs and ensure that our products will perform to this potential for years to come.