The Kora TB400 Integrated Amplifier embodies the brand’s philosophy of combining tube warmth with transistor power. The TB400 is, quite simply, the TB200’s big brother. More filtering, bigger transformers, more transistors. At its heart lies the innovative SquareTube® operational amplifier, equipped with four triodes per channel. This unique design ensures that all amplification and signal control functions are handled by the SquareTube®, while complementary hyper-linear power transistors supply the necessary current to drive your speakers without coloring the signal. The result is an amplifier that maintains absolute phase accuracy, delivers extraordinary detail, and achieves natural dynamics with unmatched musicality. By eliminating the limitations of traditional output transformers, the TB400 avoids phase shifts, poor coupling, and current restrictions. Its marriage of high-voltage tube smoothness and transistor-driven energy delivers a rich, stable, and precise performance—even under complex load conditions. With the TB400, music is experienced with both refinement and unrestrained power. Square Tube Technology The TB400 features Kora’s exclusive Square Tube Technology, a hybrid design that bridges the best qualities of tubes and solid state. By shaping the signal with tubes at the input stage and preserving their harmonic richness, while allowing a robust solid-state output stage to provide control and drive, the TB400 achieves a rare balance of warmth, transparency, and authority. This design eliminates many of the compromises found in traditional tube or transistor circuits, offering the musicality of tubes with the reliability and power of solid state. Learn more about Square Tube Technology. Key Features SquareTube® Technology – Four triodes per channel provide full amplification and signal control for a uniquely musical presentation. Tube + Transistor Synergy – Tubes add smoothness while transistors deliver dynamic, unrestrained energy. No Transformer Limitations – Eliminates phase shifts in both low and high frequencies, ensuring accurate reproduction. High Voltage & High Current Design – Combines tube voltage capacitance with transistor current for exceptional definition and impact. Exceptional Stability – Remains precise and natural even with demanding or complex speaker loads. Natural Dynamics – Extracts subtle detail and spatial accuracy for an engaging, lifelike listening experience. 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. Whether you’re visiting in person or ordering online, we bring decades of experience, personalized service, and honest guidance to every interaction. We don’t just ship boxes. We help build systems, answer your questions like real humans, and make sure every detail of your setup is right, from the cables to the final connection. Our passion is helping you get the most out of your gear, with support that lasts well beyond the sale. Specifications General Characteristics Overall dimension 148 × 420 × 450 mm Chassis size only 130 × 420 × 420 mm Unit weight 27 kg Manufacturer’s warranty 5 years Materials Aluminium and steel Finish Mineral grey Accessories Metal remote control, power cord, instructions Construction & design Toulouse, Occitania region, France Electronic Features Power supply IEC 230 V AC socket, +7% ~ -10% (117 V AC on request) Maximum power input 2 × 360 W / 4Ω : 1010 VA Maximum power consumption 2 × 200 W / 8Ω : 610 W Internal power supply 2 × (± 65 V DC), dual power supply Power supply transformer 2 × 500 VA, auxiliary supply: 5 DC/DC converters, 2 linear regulators Main filtering 2 × 100 000 μF High voltage +300 V stabilised, -200 V stabilised Input tube heater 2 × 12 V DC, regulated and grounded voltages Output tube heating 2 × 12 V DC, isolated regulated voltages Output power 2 × 200 W / 8Ω, 2 × 360 W / 4Ω Output power distribution 20 complementary highly linear power transistors “ON SEMI” (225 W / 15 A each) Inputs – 4 line inputs, input impedance: 15 kΩ– RCA connectors– Input sensitivity: 1 V– Pre-out, output impedance: 2 kΩ– Input 4 can be configured as bypass (power amplifier mode)– Input 4 can also be configured as pre-out after volume control (e.g., external subwoofer) Bandwidth 20 Hz ~ 20 000 Hz, ± 1 dB Internal impedance Output: < 0.08 Ω
