Allnic Audio has released a Class AB power amplifier called the A-2000 mk3 . The developers use KT170 tubes in it, and its output power is 120 W in pentode mode and 60 W in triode mode.
One tri-connected 5654 pentode tube per channel is used in the first stage to provide 26 dB of voltage gain, and two 6S4 triode tubes per channel are used as the phase inverting and excitation tubes to push-pull the KT170 output tubes. Also in the A-2000 MK3, engineers used two proprietary Allnic output transformers with a permalloy core, one per channel.
The A-2000 MK3 boasts many signature Allnic features , including polycarbonate tube flues, output tube current meters, bias current adjustment potentiometers, and on-the-fly pentode/triode output tube mode conversion with a simple button.
Also important is the slow start mechanism, which ensures stable operation of the vacuum tube when the power is turned on. The rear interfaces consist of one pair of XLR and RCA input jacks and one pair of speaker cable jacks for left and right channels. There is a toggle switch to select between 4 ohm and 8 ohm output impedance for easy speaker matching. The A-2000 MK3 has an input impedance of 100 ohms and a damping factor of 8, delivering exceptionally powerful, defined bass.