The Grand Stereo is a dual mono and a true balanced design that literally is two amplifiers built into a single chassis (and thus requires two separate AC power cords). Keeping the signal path as short as possible, each output stage of the amplifier employs nine pairs of ultra-fast Sanken bipolar power transistors. As a result, it has a total current capability and instantaneous peak current delivery of 120 Amperes and is a high bandwidth circuit design with a frequency response of an impressive DC-500 kHz
(0/+-3db). The maximum swing voltage is 75V. It's a powerhouse, producing 650 watts per side into 8 ohms, 1,000 watts into 4 Ohms and 1,800 watts into 2 Ohms with an impressive damping factor of 10,000 into 8 Ohms, 20 Hz - 20,000 Hz (It's hard to imagine needing even more power, but if you dreamed of such things their Grand Mono delivers an even more remarkable 2,400 watts per side at 8 Ohm with finesse and control). In the Grand Stereo each channel uses a custom made low noise high current 1,800 VA toroidal transformer with 240,000 uf of total capacitance for both channels. They are in a separate aluminum enclosure to isolate and to minimize any bad influences on the audio section. The chassis are made of top notch aircraft aluminum imported from Switzerland. Karan utilized many custom made components, according to his specifications, sourced from Germany. For example, non-magnetic low noise resistors that are 6 dB lower than what are typically used in Karan electronics. Also, newly designed capacitors with lower inductance boast more current and speed.
Cleverly, the Grand Stereo amp operates in Class-A, with what Tchang describes as (floating) active bias mode. Karan explains that the Grand Stereo works unlike any other active bias design. In Karan's design an electronic circuit monitors the incoming signal and introduces a small amount of bias on the output stage when the circuit is in standby. When a musical signal is detected, the circuit measures the amplitude of signal and opens the output stage (increasing bias) and the current rails on the output transistors instantaneously. This way the output transistors always keep the right amount of current and temperature to maintain the same quality performance with minimum heat and energy loss. Whether played loud or soft, the Grand Stereo always felt warm to the touch. The Grand Stereo also uses zero negative feedback throughout. As noted above, the chassis is finished in meticulously crafted high-quality Swiss aircraft aluminum to help reduce mechanically induced jitter. It's quieter, more dynamic and open sounding without any compression on the signal as compared to other materials says Karan.To minimize resonances further, Finite Elemente Ceraballs are incorporated as well. There are two AC Power On switches on the back of the Grand Stereo, one balanced (XLR) and one unbalanced (RCA) input with two pairs of binding posts for bi-wiring.
Power: 650 W into 8 Ohms, 1000 W into 4 Ohm, 1800 W into 2 Ohms
Maximum instantaneous current: 120A peak
Maximum voltage swing: 70V
Class A active bias operation
Frequency response: DC-500 Khz+0/-3 dB