LAB12 Suara Mk2 Toroid Class-A Tube Amplifier at Vinyl Sound Buffalo NY

The Suara Mk2 Toroid is a parallel single-ended Class A tube power amplifier from LAB12 (Athens, Greece), available at Vinyl Sound in Buffalo, NY. Delivering 50 watts per channel from four KT150 power pentodes in a parallel SET topology, it bridges the harmonic beauty of pure single-ended design with the current authority needed to drive full-range loudspeakers. A selectable triode and ultralinear operating mode gives the listener direct control over the amplifier's presentation, while dual toroidal power transformers ensure a clean, stable power foundation across both modes. The Suara has earned the Editor's Choice Award from Hifi Pig Magazine, reflecting its standing as a rare Class A tube amplifier capable of real-world speaker compatibility.

Parallel Single-Ended Class A Topology

The Suara Mk2 Toroid uses a parallel single-ended Class A circuit, an architecture that combines multiple output tubes wired in parallel to deliver the tonal richness and harmonic completeness associated with single-ended triode amplification at power levels that conventional single-ended designs cannot achieve. Where a traditional SET amplifier might produce 8 to 12 watts per channel, the Suara Mk2 Toroid generates 50 watts per channel, placing the loudspeaker compatibility of the design well beyond the narrow band of high-efficiency speakers traditionally required for SET listening. The result is an amplifier that captures the texture, decay, and three-dimensionality of the best single-ended designs while accommodating a far broader range of loudspeakers, including 4 to 8 ohm designs of moderate sensitivity.

Toroidal Power Supply and Triode / Ultralinear Flexibility

Dual toroidal power transformers form the backbone of the Suara Mk2's power supply, providing the high current reserve and low electromagnetic interference that Class A operation demands. The triode and ultralinear mode selector on the rear panel allows the listener to choose between the intimate warmth and harmonic density of triode operation and the greater bandwidth, tighter bass, and extended headroom of ultralinear mode, without requiring any circuit modification or special tools. Rear-panel manual bias adjustment is straightforward and accessible, making tube maintenance a practical rather than a technical exercise. LAB12's SRSG grounding and Fine Symmetry circuit layout are applied throughout, ensuring that the signal path remains isolated from power supply noise and that both channels track each other precisely.

Key Features

• Parallel Single-Ended Class A Topology: A unique circuit architecture that delivers the harmonic richness of SET design with 50 watts per channel, far exceeding conventional single-ended power limits.
• KT150 Output Tubes (quad): Factory-installed KT150 power pentodes; compatible with 6550, KT88, and KT120 for tube rolling flexibility.
• Dual Toroidal Power Transformers: One transformer per channel provides high current delivery and low-noise power to the Class A output stage.
• Triode / Ultralinear Mode Selector: Rear-panel switch allows the listener to choose between two distinct operating modes with meaningfully different sonic characters.
• SRSG Grounding: Separate Rails Separate Grounds implementation keeps signal and power ground paths fully isolated throughout the circuit.
• Fine Symmetry Layout: Precision circuit geometry ensures matched performance between channels.
• No-Feedback Design: Zero global negative feedback for a natural, open presentation.
• Rear-Panel Manual Bias Adjustment: Easily accessible bias trimmers on the rear panel simplify tube maintenance without requiring amplifier disassembly.
• Analog Nissei VU Meters: Classic analog level meters provide real-time visual monitoring of output levels.
• Precision 5mm Aluminum Panel: CNC-machined face panel available in Matte Black or Frozen Silver with a glass-blasted anodized finish and five-year manufacturer guarantee.

Technical Specifications

Awards and Critical Recognition

• Editor's Choice Award – Hifi Pig Magazine

Frequently Asked Questions

What is the LAB12 Suara Mk2 Toroid?

The LAB12 Suara Mk2 Toroid is a parallel single-ended Class A tube amplifier from Athens, Greece, producing 50 watts per channel from four KT150 power pentodes. It combines the harmonic richness of single-ended design with the current delivery needed to drive real-world loudspeakers, offering selectable triode and ultralinear operating modes, dual toroidal power transformers, rear-panel manual bias adjustment, and analog Nissei VU meters in a precision 5mm aluminum chassis.

How does the Suara Mk2 Toroid compare to the Rogue Audio Cronus Magnum III?

The LAB12 Suara Mk2 Toroid and the Rogue Audio Cronus Magnum III are both powerful tube amplifiers capable of driving a wide range of loudspeakers, but they differ fundamentally in circuit topology and design intent. The Suara Mk2 Toroid is a parallel single-ended Class A design, prioritizing the harmonic texture and three-dimensional imaging that SET listeners value, with dual toroidal power transformers and a no-feedback circuit. The Cronus Magnum III is a conventional push-pull pentode design with an integrated phono stage and headphone output, offering greater all-in-one convenience for a complete analog system. The Suara Mk2 is the stronger choice for listeners who want the sonic character of Class A single-ended amplification without the speaker limitations of low-power SETs.

Can the Suara Mk2 Toroid drive moderate-sensitivity loudspeakers?

Yes. The Suara Mk2 Toroid's 50 watts per channel from a parallel Class A circuit gives it the current authority to drive loudspeakers with sensitivities in the 86 to 91 dB range, including designs such as the PSB Synchrony T600 or the Wharfedale Evo 4.4. Its Class A output stage maintains its full character across the dynamic range, avoiding the crossover distortion artifacts that can surface in Class AB designs at low listening levels. The recommended 4 to 8 ohm speaker load covers the vast majority of contemporary audiophile loudspeakers.

What is the difference between triode and ultralinear mode on the Suara Mk2?

In triode mode, the output tubes are configured to operate as triodes by connecting the screen grids to the plates, producing a softer, more harmonically dense sound with a characteristically intimate midrange and reduced overall power. In ultralinear mode, the screen grids are tapped into the output transformer at a fixed percentage of the primary winding, which recovers power output, extends bandwidth, and tightens bass control at the cost of some of the triode-mode warmth. The Suara Mk2 Toroid's rear-panel selector makes it possible to switch between both modes and identify which presentation best suits the listener's speakers and musical preferences.

What tubes are compatible with the Suara Mk2 Toroid?

The Suara Mk2 Toroid ships with four KT150 power pentodes as the factory-installed output tubes. The design is also compatible with 6550, KT88, and KT120 tubes, giving the owner meaningful latitude for tube rolling. Power output will vary by tube type, with KT150 delivering the full 50-watt specification. Bias adjustment is accessible via rear-panel trimmers, making tube changes straightforward without requiring specialized tools or external equipment.

Does the Suara Mk2 Toroid accept both RCA and XLR inputs?

Yes. The Suara Mk2 Toroid provides a single stereo line input that accepts both RCA and XLR connectors, allowing connection to preamplifiers or source components with either unbalanced or balanced outputs. The input impedance is 100 kΩ, which is compatible with virtually any line-level preamplifier or DAC. When using the XLR input, the input sensitivity shifts slightly between triode and ultralinear modes, so it is worth confirming output levels from the source component when optimizing the system gain structure.

Where can I buy the LAB12 Suara Mk2 Toroid in Buffalo, NY?

The LAB12 Suara Mk2 Toroid is available at Vinyl Sound in Buffalo, NY, an authorized LAB12 dealer serving Western New York and the USA. Vinyl Sound carries the complete LAB12 amplifier lineup and can assist with in-store demonstrations, system pairing advice, and finish selection between Matte Black and Frozen Silver.