ProLogue Premium Mono Amplifier

Incorporating the best electronic elements of the original ProLogue Six and Seven, plus selected ground-breaking features from the more advanced DiaLogue Series, the next generation ProLogue Premium Series is an engineering marvel — a single pair of monoblock amplifiers that sets a new benchmark in high-performance audio with the following features:

• Innovative, new Adaptive AutoBias circuitry. By simply flipping a switch, users can re-calibrate the monoblocks for optimum operation of EL34s or KT88s. Every ProLogue Premium Series amplifier can be ordered with either set of power tubes installed. And remember, this circuit continuously monitors and adjusts each tube to run in its sweet spot. No biasing—ever!
• Solen capacitors and fast-recovery diodes. Made in France, Solen caps give greater definition and more natural tonality, while fast-recovery diodes in the power supply provide greater control during complex musical passages.
• New output and power transformers. Modeled after those in the more advanced DiaLogue Series, these heavy-duty, high-efficiency transformers offer better control over challenging speaker loads, as well as increased detail and musicality.
• New front-end circuitry. Optimized to use two 12AU7 tubes per channel. With the improved transformers, produces lower distortion.

The ProLogue Premium Series introduces four innovative circuits to protect the amp at every level:

• BTI-circuit. BTI stands for “Bad Tube Indicator.” On the chassis’ deck in front of each power tube, is a small LED that lights up if the tube goes bad. This circuit works hand-in-hand with the new Adaptive Auto-Bias circuit.
• PTP-circuit. If the power transformer should overheat, this “Protect the Power transformer” circuit cuts primary power, allows the amp to cool down, then resets itself.
• OTP-circuit. The “Output Transformer Protection” circuit protects the output transformers in the event of a massive tube failure or user error.
• +B relay. Replaces the plate fuse and works in conjunction with the OTP-circuit to protect the amp against tube failure. This method is less intrusive sonically and the relay resets itself once the faulty tube is replaced.
• The finest point-to-point wiring and quality equal to –or better than- any amplifier you can buy at any price. Built with the highest quality parts including fully-vented, ceramic tube sockets; Nichicon capacitors; WBT-style core speaker terminals; gold-plated RCA jacks; toroidal power transformer.
• SoftStart™ circuitry and advanced conservative design reduces shorts and extends tube life.
• Hand-rubbed, high gloss finish with black or silver faceplate. Quick-release tube cage included.

The ProLogue Premium Mono Amplifier then leaps forward with unique dual-feedback topology: cross-coupled current feedback for superior impulse behavior and gain stability. Next a slight amount of negative feedback is used to achieve exact gain setting, low distortion, and low output impedance. This effectively cancels the negative by-products associated with both feedback circuits. The end result utilizes all the benefits of feedback, without all the drawbacks.

Finally, the monoblocs integrate specially designed, wide-band, low-loss output transformers, built to handle even the most difficult speaker loads. A two Ohm output tap is added for additional flexibility.