Theta Digital Citadel Monoblock Amps (Pair)

These Citadel 1.0 amplifiers are in pristine condition. Their performance was verified at the factory and locally last year and remain in the original shipping cartons they were returned in. They have no known service issues. One owner, non-smoking environment.

Palletized shipping is recommended! They weigh 130 pounds each in carton. They must be shipped to a PayPal verified address. PayPal fees, freight and insurance will be added. Bank wire will avoid PayPal fees.

"The sound of the Theta Digital Citadel monoblocks can be summed up in a single word: delightful."
-Jonathan Scull

Read more at https://www.stereophile.com/content/theta-digital-citadel-monoblock-amplifier-page-3#EGDymAdUWDIv2iys.99

http://thetadigital.com/downloads/Theta%20Digital%20Citadel%20owner's%20manual.pdf

https://www.stereophile.com/solidpoweramps/576/index.html

The Citadel was a monaural power amplifier. It was as great an amplifier as Theta's engineers, building on the knowledge gained in the design and refinement of the Dreadnaught, knew how to make. Citadel embodied a level of performance Theta could produce when the design team was not much constrained by concerns of cost, although it was also true that nothing spent on the Citadel was frivolous. Citadel was built to stand up to the most demanding systems. More than an iron fist, Citadel was made for delivering exquisitely revealing two-channel music reproduction. And Citadel was the best choice for powering home theater systems, as it packed the massive power to recreate even the most spectacular, floor-shaking, chandelier-rattling soundtracks. The heart of the Citadel was fully-balanced differential, zero-feedback circuitry. Component parts in every stage were selected for optimum performance, and for 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 contributed to the performance. Citadel's power supply was an exercise in brute power and complete control. The output stage had a high-current Kilowatt power transformer, which fed a unique dual-choke and capacitive filtering system. This technique was rarely applied because of the huge choke size necessary to avoid impeding high current demands. Citadel's filtering system employed two massive chokes almost as large as the power transformer. These were fed from an ultra-fast / soft-recovery 35 Amp full bridge rectifier, which was then filtered by two capacitive banks totaling 80,000uF. The synergistic effect of this filtering system resulted in high-current power supply lines that were more than 8000% cleaner than conventional supplies. The sonic result of these super clean supply lines to the output transistors had not previously been achieved at high power levels. The mechanical housing for Citadel was no less specialized than its internal components. More than an aesthetic statement, its seamless housing, free of traditional fasteners on top, front, and sides, provided a strong and stable environment for the operation of the amplifier. The power supply resided in its base, isolated from the amplifier module above. Nominal power rating for the Citadel was 400 Watts into 8 Ohms.