VK-85 Preamplifier
Available in silver or black
Introduced simultaneously with the REX 300 power amplifier, the Balanced Audio Technology VK-85 preamplifier blurs the lines between the finest tube and solid-state sound. VK-85 features BAT’s trademark high-current Unistage topology with transformer-coupled outputs that anchor the full line of Balanced Audio Technology’s preamplifiers. VK-85’s second-generation output transformers work in conjunction with a symmetrical N-channel Unistage gain block to provide the high-current operation that is a BAT hallmark. A revised connection scheme for the SuperPak Quattro technology used in REX 300 offers beguiling levels of musical finesse and textural beauty.
SuperPak Quattro
The revised power supply of VK-85 incorporates the same fourth-generation SuperPak used in REX 300. In addition to providing four levels of filtration, it is connected in a new manner that dramatically lowers the preamplifier’s overall noise floor. The parts used in SuperPak Quattro include premium silver foil/oil capacitors that improve harmonic accuracy — and go far beyond the red chiclet-style caps found in most power supply bypass designs.
Unistage Design
Simplicity of design, especially in the direct signal path, remains a hallmark of Balanced Audio Technology’s purist approach to circuit topology. The signal in VK-85 is transmitted through only one gain stage — one free from the negative artifacts attributable to both extremes of modern preamplifier design: passive preamplifiers and multi-stage buffered active circuits. BAT’s trademarked Unistage circuit provides the ultimate simplicity of amplifying the incoming signal just once while using no global feedback to double-back on the integrity of that signal.
High-Current N-Channel MOSFET Circuit
The VK-85 circuit is based on N-Channel MOSFET devices. Solid-state designs customarily use complementary N- and P-Channel devices in the gain stage. Such configurations are easier to build but suffer from an important drawback: P-Channel devices are inherently inferior to their brethren because they are much slower. In VK-85, both sides of the waveform are handled by identical devices – in identical circuit configuration – assuring symmetry of the resulting signal.
VK-85 Preamplifier
Specifications
Inputs
3 XLRs + 2 RCAs
Outputs - Main
2 XLRs
Outputs - Tape
1 RCA
Maximum Gain
20dB
Global Feedback
None
Volume Control Resolution
.5dB
Volume Control Number of Steps
140
Frequency Response
2Hz to 200kHz
Input Impedance (minimum)
100k each phase
Output Impedance
200 ohm each phase
Noise (unweighted)
-96dB
Distortion at 2V output
.01%
Maximum Output Signal
20V
Absolute Polarity
+/- via front panel switch
Power Consumption
250VA
Tube Complement
80VA maximum
Dimensions
19" x 5.75" x 15.5"
Weight
40 lbs.