Balanced Audio Technology VK-255SE Power Amplifier (OPEN)

The VK-255SE power amplifier represents Balanced Audio Technology’s hallmark out-of-the box approach to audio circuit design. Unlike most solid-state amplifiers that feature four or more gain stages in a high-feedback push-pull configuration, the VK-255SE features only two gain blocks in a high-power, zero feedback, and purely symmetrical design. Available as either a stereo or monoblock unit, the VK-255SE has the warmth and texture typically associated with the finest vacuum-tube designs combined with the dynamic capability of the best solid-state offerings.

The VK-255SE power amplifier represents Balanced Audio Technology’s traditional out-of-the box approach to audio circuit design. Unlike most solid-state amplifiers that feature four or more gain stages in a high-feedback push-pull configuration, the VK-255SE features only two gain blocks in a high power, zero feedback, and purely symmetrical design. Available as either a stereo or mono-block unit, the VK-255SE is a superb amplifier that features the warmth and texture typically associated with the finest vacuum tube designs, combined with the dynamic capability of the finest solid-state offerings.

Only Two Gain Stages (with Zero Global Feedback)

The VK-255SE’s elegant signal path follows the Balanced Audio Technology purist approach of using zero negative feedback to achieve the design goals of wide bandwidth and circuit linearity. The whole amplifier circuit consists of just two gain blocks! The theoretical ideal for any power amplifier would be to have only one gain block, but this has been achieved only with the limitation of low power output. Thus, the VK-255SE is at the zenith of simplicity for any modern high-power amplifier design.

Needless to say, the VK-255SE is fully balanced from input to output. To complement the inherent simplicity of this fully balanced design, only the highest grade parts are used throughout, yielding a superbly transparent insight into the musical event.

N-Channel MOSFET Devices Used

The VK-255SE circuit is based entirely on N-Channel MOSFET devices.

It is customary in high power amplifiers to use the complementary N- and P-Channel devices in the output stage. Such configurations are easier to build, but they all suffer from one important drawback: the P-Channel devices are inherently inferior to their N-Channel brethren. They are simply much slower. Pairing the faster N-channel devices with the slower P-channel devices is like pairing Ginger Rogers with her horse on the dance floor – instead of Fred Astaire. You will never get perfect symmetry when using devices with such a wide discrepancy in speed.

In the VK-255SE power amplifier, both sides of the waveform are handled by identical devices, in identical circuit configuration, assuring ultimate symmetry of the resulting signal.

300 Watts per channel (Stereo) into 4 Ohm

The VK-255SE stereo power amplifier is a high-current solid-state design that offers a robust 300 watts per channel into a four ohm load. This is a stellar power amplifier that can easily drive the typical speaker with great dynamic ease. The mono-block version of the VK-255SE amplifier doubles the current delivery of the stereo version – yielding additional drive capability for even the most difficult loads in the largest home environment. With this flexibility, the Balanced Audio Technology VK-255SE amplifier can serve as the anchor in any world-class audio system.

Second–Generation Super-Pak

The revised power supply of the VK-255SE now incorporates the same second-generation oil-filled capacitors used in Balanced Audio Technology’s new REX II Preamplifier. These second generation oil capacitors increase the high quality filtering capacity by an order of magnitude over the first generation oil parts. The result is a dramatic lowering of the power amplifier’s noise floor combined with a grain-free, yet textured, and more refined portrayal of musical harmonics.

Intelligent Power Upgrade

The VK-255SE can be ordered from the factory as either a stereo amplifier or as a mono-block in the VK-255SE_M version. Balanced Audio Technology also provides a transparent upgrade path that allows the owner of a stereo VK-255SE to easily convert to a mono-block at any point in time.

Unlike competing designs, there is no need for the user to trade their amplifier in to obtain greater drive capability. With the VK-255SE Power amplifier, the user can simply convert their existing VK-255SE to a mono-block, and then order a second VK-255SE mono-block to match. Technically, the stereo to mono-block conversion is accomplished by simply paralleling the inputs and outputs. This means that “the sound” only gets better as the VK-255SE mono-block current delivery is doubled. The added current delivery makes the sound of the VK-255SE_M effortless – more akin to that of the master tape.

Summary

The Balanced Audio Technology VK-255SE power amplifier markedly closes the performance gap between vacuum tube and solid-state amplification. With the VK-255SE power amplifier, you will enjoy the harmonic richness typically associated with the finest tube amplification, combined with the dynamic capabilities of the best high-current solid-state designs. The VK-255SE couples speed and grace with an exquisite fidelity to the timbre and texture of instruments and voices. Indeed, the sound of the VK-255SE converges upon BAT’s ultimate goal – the sublime reproduction of music – independent of the devices employed. We invite you to visit your BAT audio specialist to hear the extraordinary performance of the VK-255SE for yourself. All you need to do is listen!

Specifications

Output per channel at 8 Ω / 4 Ω: 175 W / 350 W 
Frequency Response: 2 Hz to 150 kHz
THD at full power: 0.2 % 
Input Impedance: 100 kΩ balanced
Power Consumption (Idle/Full Power): 50 W / 1500 W 
Dimensions (WHD): 19" x 5.5" x 14.5" 
Weight: 75 lb