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THE CITADEL 1.5 IS A MONAURAL POWER AMPLIFIER OFFERING ALL THE ADVANTAGES OF THE KNOWLEDGE, RESEARCH AND DEDICATION THAT TEAM THETA BROUGHT TO THE DREADNAUGHT--AND THEN SOME.

Citadel has been created to power the most demanding two channel music reproduction systems, as well as delivering abundant power to home theater systems, to effortlessly recreate the vast spectrum of soundtracks.

The heart of the Citadel is fully-balanced differential, zero-feedback circuitry, and zealously selected solid-state devices throughout. We scrutinize the selection to optimize component parts in each and every stage, and for the performance of the amplifier as a whole. Custom-made capacitors, Vishay precision resistors, copper buss bars, Litz/Teflon wires, and a custom-made output connector are just some of the components that combine to make Citadel an unprecedented technical statement.

Sonically, this is expressed as a new level of veracity and intimacy in the experience of music, and in the prospect of movie performance that no theater can hope to rival.

Power

Citadel's power supply is an exercise in delivering massive brute power with absolute integrity.

We give the Citadel's output stage a high-current Kilowatt power transformer itself, which feeds a unique dual-choke and capacitive filtering system.

This technique is rarely applied because of the huge choke size necessary to avoid impeding high current demands. Citadel's filtering system employs two massive chokes almost as large as the power transformer. These are fed from an ultra-fast/soft-recovery 35 Amp full bridge rectifier, which are then filtered by two capacitive banks totaling 80,000uF. The synergistic effet of this filtering system results in high-current power supply lines that are more than 8,000% cleaner than conventional supplies.

The sonic result of these super-clean supply line to the output transistors has not previously been achieved at such a high power levels.

The mechanical housing for Citadel is no less specialized than its internal components. More than an aesthetic statement, it's seamless housing, devoid of traditional fasteners on top, front, and sides, provides a strong, stable environment for the operation of the amplifier. The power supply resides in its base, isolated from the amplifier module above.

Can an industry standard change?
Yes. We’ve moved the benchmark.

Over the last six years, the Citadel has been improved by a series of evolutionary changes, such that we feel the upgraded amplifier has earned the designation Citadel 1.5.

Though the basic nature of the amplifier remains the same, these performance enhancements , cumulatively, make the current amplifier even more musically rewarding, and more revealing than the original Citadel.

Highlights

Nominal power rating: 400 Watts into 8 ohms (What it really does: 425 into 8, 650 into 4, 800 into 2)

Custom-made polypropylene capacitors

Cardas 9 gauge Litz/Teflon wire

Solid copper buss bars for power supply lines, output lines

Ultra-fast/soft recovery bridge rectifiers for regulated and high-current supplies

Unique dual choke/capacitive filtering system

Gold-plated RCA and XLR input connectors

Custom-made, high-pressure contact Delrin/Rhodium plated output connector, tool provided for tightening

Rear panel LED indicator for fuses and thermal overload

Rear panel jacks for remote control of Mute/Standby and Input Selection

Slot for future upgrade expansion

Separate A.C. lines for analog power and digital circuits

RS-232 connections for computer controls and status information

Control tower buttons for Mute/Standby and Input Selection; LED indicators for Mute/Standby, Input Selection, and Thermal Overload.