Rogue Audio Stereo 100 Amplifier

The Rogue Audio Stereo 100 is a reference-grade stereo tube power amplifier that delivers 100 watts per channel from four KT120 output tubes through ultra-wide bandwidth output transformers and Mundorf EVO Oil coupling capacitors. With switchable triode/ultralinear operation, a built-in bias meter, and a fully regulated high-voltage power supply, the Stereo 100 brings the component quality of Rogue's flagship Apollo amplifiers down to a more accessible price point.

Key Features of the Stereo 100

• 100 Watts Per Channel (Ultralinear): Four KT120 output tubes in push-pull deliver 100W into 8 ohms, with a switchable 60W triode mode for tonal flexibility
• Mundorf EVO Oil Coupling Capacitors: Premium signal-path capacitors included as standard equipment, not reserved for the Dark version
• Ultra-Wide Bandwidth Output Transformers: Custom-wound transformers with frequency response from 5Hz to 50kHz (±1dB), far wider than typical tube amplifier designs
• Mechanically Isolated Transformers: Power and output transformers are mechanically decoupled from the chassis to prevent microphonic vibration from reaching the circuit
• Fully Regulated High-Voltage Supply: Massive regulated power supply provides stable, clean voltage under all operating conditions
• Built-In Bias Meter: Front-panel bias meter with external adjustment points for quick, tool-free tube management
• Integral Tube Cage: Included welded-wire tube cage protects output tubes during use
• Handcrafted in the USA: Designed and built in Brodheadsville, Pennsylvania, with every unit tested, burned in, and auditioned

What Sets the Stereo 100 Apart

The Stereo 100 shares its basic topology with the Atlas Magnum III (same KT120 output tubes, same 100W/60W power ratings, same triode/ultralinear switching), but the components surrounding that topology are substantially upgraded. The Mundorf EVO Oil coupling capacitors, which most manufacturers reserve for their flagship or "premium upgrade" models, are standard equipment in every Stereo 100. The custom-wound output transformers extend frequency response to 5Hz-50kHz, more than an octave wider than the Atlas on both ends. And mechanical isolation of the transformers eliminates a common source of tube amplifier noise: vibration coupling from the heavy iron into the signal path. These are the upgrades that separate a very good tube amplifier from a reference-caliber one.

Tube Amplifier Architecture

The Stereo 100 uses four KT120 output tubes in a push-pull configuration, driven by two 12AX7 voltage gain tubes and two 12AU7 phase splitters. The KT120 is a modern beam tetrode with exceptional power handling and service life, typically lasting 3,000 to 5,000 hours before replacement. All tubes are user-replaceable and widely available from multiple manufacturers, including Gold Lion, JJ, Tung-Sol, and Electro-Harmonix. The entire signal path is built on Rogue's signature heavy 2-ounce copper circuit board with precision components and short signal paths.

Ultralinear and Triode Operation

A rear-panel switch toggles between ultralinear mode (100 watts, maximum headroom and dynamic authority) and triode mode (60 watts, smoother harmonic structure with a more liquid midrange). The switch is accessible during playback and takes effect immediately, letting you match the amplifier's character to the music or the hour. Many Stereo 100 owners run ultralinear for critical listening and dynamic material, then switch to triode for late-night sessions and acoustic recordings.

Power Supply Design

The Stereo 100's power supply uses a massive, fully regulated high-voltage design that maintains stable rail voltages regardless of signal demands. This is a step above the unregulated designs found in many tube amplifiers at this price, where rail voltage sag under heavy loads can compress dynamics and soften transients. The regulated supply keeps the Stereo 100's output stage operating in its linear region even during demanding passages, contributing to the amplifier's reputation for bass control that rivals solid-state designs. Slow-start turn-on sequencing protects tubes from thermal shock at startup.

"Dark" Version

The Stereo 100 Dark ($4,995) applies Rogue's comprehensive upgrade package to the already well-specified standard amplifier:

• Enhanced Power Supply: Additional capacitance with Hex Fred high-speed diodes and polypropylene bypass capacitors for even greater dynamic reserves
• Mundorf Silver Gold Oil Capacitors: The standard Mundorf EVO Oil caps are replaced with Mundorf's flagship Silver Gold Oil coupling capacitors for maximum transparency
• Upgraded Tube Complement: Premium matched KT120 output tubes and upgraded small-signal tubes from Psvane, Telefunken, or RCA
• Cardas Rhodium Connections: Rhodium-plated RCA inputs and Cardas binding posts throughout
• Nude Vishay Resistors: Precision resistors in critical input stages with Cardas internal wiring

The Dark upgrade takes the Stereo 100 into territory shared with Rogue's flagship Apollo Dark amplifiers. The Mundorf Silver Gold Oil capacitors alone represent a significant investment in signal-path transparency.

Explore the Full Rogue Audio Power Amplifier Lineup

The Stereo 100 sits at the heart of Rogue Audio's power amplifier range, offering reference-grade components in a stereo chassis:

• Atlas Magnum III - Same tube topology at a lower price point. A strong performer that trades the Mundorf caps and wide-bandwidth transformers for value.
• DragoN Power Amplifier - 300W hybrid with tube preamp and Hypex N-Core Class D output. More power, balanced XLR inputs, and zero maintenance, in a different sonic character.
• M-180 Monoblocks - 180W pure tube monoblocks with balanced XLR inputs and Stereophile Class A status. The next step when you want dedicated amplification per channel.

Pairing with a Rogue Preamplifier

At the Stereo 100's performance level, the preamplifier becomes the dominant voice in the system. The RP-5 v2 makes a natural match at a similar price point, while the RP-7 v2 and RP-9 v2 extract every bit of resolution the Stereo 100's Mundorf caps and wide-bandwidth transformers can deliver.

The Listening Room Difference

We're a third-generation family business with a brick-and-mortar showroom in Chestertown, Maryland, and a reputation built on trust, not hype. We've carried Rogue Audio for years because their products deliver real value and hold up over time. Every component is designed and built in Pennsylvania, and we're proud to support a manufacturer that shares our commitment to quality. Whether you're visiting in person or ordering online, we bring decades of experience, personalized service, and honest guidance to every interaction.

Stereo 100 Specifications