Just over the D.C. line, Linear Tube Audio handbuilds its gear, and for its tenth anniversary, it’s unveiling the Century Monoblocks: high-powered ZOTL (Zero-Hysteresis Output Transformerless) amplifiers developed with David Berning. Priced at $28,000 per stereo pair, the Century Monoblocks ship first in brushed Quicksilver this November, with Carbon Black later this year. LTA, already known for some of the best headphone amplifiers on the planet, now brings that craftsmanship to a flagship monoblock design.
The Century Monoblocks mark a decade of innovation, inspired by the endurance of the century ride—a 100-mile cycling milestone—and aimed at audiophiles who demand both power and finesse. Combining LTA’s latest advancements with ZOTL architecture, the Century Monoblocks deliver performance capable of driving demanding speakers, including electrostatics, planars, and low-sensitivity designs.
Century Monoblocks: Screen-Drive ZOTL and High-Performance Tube Amplification
For the first time in LTA’s lineup, the Century Monoblocks use a screen-driven output stage within the ZOTL architecture. EL84 pentodes control the screen grids of NOS 6JN6 beam power tubes, combining the efficiency of pentode operation with the linearity and smoothness of triodes. The result is detailed, fast, and uncolored sound with remarkable depth.
Traditional tube amps can struggle with complex or capacitive speaker loads, causing frequency shifts and reduced control. The Century Monoblocks address these issues with a low output impedance and wide bandwidth. Their transformerless design removes hysteresis, phase shifts, and the frequency-dependent distortions common in transformer-coupled amplifiers. The outcome is the speed and grip of solid-state electronics, paired with the dimensionality and holographic soundstage of a great tube amp—effortless authority even with demanding crossovers or full-range panels.
Handcrafted Design & Modern Convenience
Each Century Monoblock is hand-built in Maryland with carefully selected components aimed at accuracy and musicality. Non-magnetic resistors, ferrite-core impedance converters, and a minimalist signal path work together to provide a precise and uncolored presentation. Voicing is finalized through extensive listening, and the non-magnetic aluminum chassis with full Faraday shielding ensures effective noise rejection.
Building on Berning’s Quadrature Z heritage, the Century Monoblocks offer low noise, improved stability, and practical features for today’s listener. These include auto-biasing, global voltage compatibility (100–260 VAC), built-in protection circuits, adjustable global feedback, and tubes designed to run cool for long-term reliability. Their transformerless design also keeps the amplifiers relatively light.
With this combination of careful design and modern features, Linear Tube Audio delivers a tube amplifier that emphasizes realism, control, and musical transparency; something has always been a core element of all LTA amplification.
Century Monoblocks: Balanced ZOTL Design, Screen-Drive Tubes, and High-Performance Specs
The Century Monoblocks offer both XLR and RCA inputs, with all amplification stages fully balanced. Each monoblock delivers 110W into 8 Ω and 144W into 4 Ω at 1% THD, remaining stable with loads below 2 Ω. For short bursts, they can produce up to 178W into 4 Ω at 1% THD, and 196W at 2% THD.
The amplifiers use a fully differential ZOTL topology with the new Screen Drive and pentode driver system, employing four NOS 6JN6 compactron beam power pentodes per channel, two EL84 pentode drivers, and three 7062/E180CC tubes in the input and gain stages.
Construction is dual monoblock with non-magnetic aluminum cases and full Faraday cage shielding. Front-panel adjustable feedback allows LOW, MED, and NORM settings, while internal components include non-magnetic resistors, boutique capacitors, and advanced ferrite impedance cores.
Outputs support dual binding posts for bi-wiring, and there is a rear-panel GND post. Modern conveniences include auto-biasing, automatic voltage selection, and built-in protection circuits, with low heat output and a 3400 V peak-to-peak power tube swing supported by approximately 1 Farad of storage capacitance.
Frequency response varies with load and feedback: at 8 Ω it spans from 1.3 Hz to 44 kHz (LOW), 1.14 Hz to 64 kHz (MED), and 1.3 Hz to 90 kHz (NORM); at 4 Ω, 1.23 Hz to 37 kHz (LOW), 1.17 Hz to 46 kHz (MED), and 1.3 Hz to 58 kHz (NORM). Input impedance for RCA ranges from 20k to 47k Ω and XLR from 28k to 94k Ω depending on feedback.
Output impedance ranges from 0.8 Ω (NORM) to 5.2 Ω (LOW). Each amplifier weighs 26.5 lbs (12 kg) and operates across 100–260 VAC, 50–60 Hz with power factor correction.
The Bottom Line
The Century Monoblocks combine Linear Tube Audio’s ZOTL architecture with a new Screen-Drive output stage using EL84 pentode drivers and NOS 6JN6 beam power tubes. Each monoblock delivers 110 W into 8 ohms and 144 W into 4 ohms, stable below 2 ohms, with short bursts up to 196 W. Fully balanced XLR and RCA inputs, low output impedance, wide bandwidth, and transformerless design make them capable of driving demanding speakers, including electrostatics, planars, and low-sensitivity designs.
Features include adjustable feedback, auto-biasing, global voltage compatibility, and hand-built dual monoblock construction in non-magnetic aluminum with Faraday shielding. We look forward to hearing them in action at CAF 2025 in a few weeks; whether LTA will unveil a Century pre-amplifier to match remains to be seen.
For more information: lineartubeaudio.com/century
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