Wonderful digital amplifier from Tact Audio, complete with room correction with supplied microphone, which ushered in a new breakthrough in simplifying the process of correcting for speaker and room anomalies. Prior models from Tact required using a computer, and the process was a bit involved. With this integrated amplifier, room correction is just a push of the button, and the whole process is completely automated, and couldn't be simpler. Furthermore, the room correction can be adjusted to compensate for human hearing characteristics (the so-called Fletcher Munson curve), which boosts the bass at low volumes. Unlike the crude loudness button in cheap receivers, this unit employs a highly sophisticated dynamic room correction filter, which can be turned off or modified as the user desires.
The design of this digital integrated amplifier exploits the fact that almost all the music we listen to starts off being stored as bits. Well, in that case, why not keep it in that form till the very last stage? This is exactly what the Tact S-2150XDM does. It is a purely digital amplifier, which accepts four digital inputs (SPDIF coax, AES-EBU, optical) up to a frequency of 192 Khz and bit depth of 24 bits. It reshapes the incoming pulse train as a pulse width modulated signal at 384 Khz of varying widths. The final stage is a passive filter which converts the PWM digital signal into analog. The volume control effectively operates by changing output voltages, and is not part of the signal path. Hundreds to thousands of active and passive components in a normal analog amplifier are completely eliminated in this pure and direct signal path.
The result is obvious in listening. The amplifier is dead silent even at maximum volume. It is no weakling, but weighs close to 40 pounds. It can produce 150 watts into 8 ohm speakers, and doubles that into 4 ohm speakers. It runs silently and remains cool to the touch even if left on all the time. It can be combined with Tact preamplifiers, or driven by any digital source (CD player, digital streamer). The Tact is revolutionary because it does no low level D/A conversion. The PCM input is converted to pulse width modulated signal, which is converted to analog using a passive filter at the output. There is no ladder type D-to-A converter. This gives it extraordinary low level linearity, up to 24 bit depth.
Power: (RMS) 2 x 150W / 8 ohm, 2 x 300W / 4 ohm
Output current: (peak, per channel) >50 A
Signal-to-noise ratio: ( A-weighted ) >110dB
Dynamic range: (20 Hz - 20 kHz) >130dB
THD+N: (all power levels 20Hz-20kHz) <0.01%
Digital resolution: 16-24 bit Linearity (-120dB) +- 0,2dB
Dimensions: (WxHxD) 450x98x420 mm
Weight: 18 kg / 37 lbs.