The A-2000 MK3 KT170 Power amplifier is Allnic Audio’s top of the line, push-pull, solid-state rectified stereo power amplifier model. Like all Allnic Audio products, the A-2000 MK3 has Permalloy (iron and nickel alloy) for its transformer cores. Allnic is grateful to Mr. G.W. Elmen of Western Electric for inventing Permalloy for transformer core use, and in so doing, providing an enormous service to recorded music listeners everywhere.
 
 
The A-2000 MK3 is an upgraded version of the original A-2000. It utilizes the new, powerful, and musical KT170 power tube, a beam tetrode, with requisite modifications to transformers, a newly redesigned heavy-duty, vibration-resistant chassis, and several minor circuit elements. The A2000 MK3 has the following features:
 
 
• 120 watts of high-power output in pentode mode, 60 watts in triode. The A-2000 MK3 is a push-pull, pentode/triode switchable stereo power amplifier.
 
 
• Powerful Driving Circuitry. Allnic believes in the importance of using high-quality, low noise and powerful driving circuitry in all its amplifying devices. Therefore, we employ the 6S4 pure triode tube in the MK3 version as the second stage driver tube. The listener can easily hear and even "feel" the differences between this design using higher loading and more current than other, more conventional, ones. Please imagine, as you listen to the A-2000 MK3, its sound compared to the sound of an amplifier using conventional 12AU7 or 12BH7 tubes as drivers.
 
 
• “Full Engagement" Output Transformers. Conventional output transformers use pre-set secondary windings to accommodate 4, 8 and 16 ohm loudspeaker loads. However, these conventional transformers utilize only one secondary winding at a time, while the other secondary windings remain "idle". This approach has two adverse effects. First, the output transformers are not working at their maximum efficiency, reducing their output relative to their potential. Second, the "idle" windings are not actually "idle"; they are subject to parasitic oscillations, producing their own "signal". This undesirable electrical information is additive to the transformer's output, distorting the amplified signal going to the loudspeaker. Allnic's "Full Engagement" transformers address these issues by having 4 independent, secondary windings that are always fully connected, never "idled". This means that all secondary windings are always connected to your loudspeakers, regardless of which output switch position you use (4 ohms or 8 ohms for the A-2000 MK3). The result is that there is neither a loss of transformer output efficiency, nor the introduction into the output signal of distortion from parasitic oscillations of the secondary windings.
 
 
• Large Nickel/FeSi Core Output Transformers. As with our other models, Allnic uses very large output transformers (96 mm) with nickel, mixed with FeSi, cores. This provides for higher inductance with fewer windings than other designs can provide and results in the great benefit of an extremely wide range of output frequencies.
 
 
• "Soft-start" Circuitry. Allnic uses soft start circuitry that, after sufficient warm-up only, provides the high voltage supply to the plate of each tube. This protective design results in prolonged tube life and fewer and less frequent issues with tube performance.
 
 
• Analogue Power Tube Current Monitors. To provide constant current (bias) monitoring for the power tubes, the A-2000 MK3 has a separate analogue current meter for each pair of power tubes. The meters offer a simple, unambiguous indication of each KT170's status compared to conventional LED bias monitors. The meters make it exceptionally easy to see the status of each tube at any time and to respond immediately to any variation in bias by use of the switchable bias control meter for each pair of KT170 tubes and the individual bias points for each KT170.
 
 
• "On-the-Fly" Triode/Pentode Switching. Switching between triode and pentode operation can be done "onthe-fly" at any time while the amplifier is in use.
 
 
• Beautiful 20KHz square wave response.