AXPONA 2024 gets underway this weekend in Chicago and there are a number of new product introductions already starting to make noise that are worth mentioning. Balanced Audio Technology (BAT) has announced the VK-85 Preamplifier and REX 300 Power Amplifier; fully balanced solid-state designs that also offer some of the sonic attributes typically found only in tube-based circuitry.
REX 300 Power Amplifier
The REX 300 is a lower-powered version of the highly regarded 500-watt per channel REX 500.
TWIN-Path and SuperPak Quattro: The REX 300 incorporates the same TWIN-Path (split power supply topology) used in the REX 500. The individual power paths allow the supply to deliver a much greater current than traditional designs.
The power supply is further enhanced by BAT’s new “SuperPak Quattro” capacitor bank which provides four levels of filtration that support better music textural beauty, tonal density, and harmonic accuracy.
No Fuses: Also, the REX 300 follows its REX 500 with a protection circuit that eliminates internal fuses, permitting it to handle higher currents without impeding the circuit’s operation.
Two Gain Blocks: REX 300 incorporates a simple high-power amplifier design thanks to a circuit that consists of just two gain blocks.
The output stage is based on “N channel” MOSFET devices (as opposed to the traditional use of complementary “N” and “P” channel devices where “P” are inherently slower and therefore inferior). This allows both sides of a waveform to be handled so that the symmetry of the resulting signal is maintained more effectively..
Intelligent Power Upgrade: For additional support, the REX 300 provides an “Intelligent Power Upgrade” option. This allows customers to order or upgrade the REX 300 as a stereo or monoblock amplifier. BAT allows an owner of a stereo REX 300 to easily convert it to a monoblock configuration at any time. There’s no need to trade in the amplifier to obtain more power.
A simple conversion of a customer’s existing stereo REX 300 to a monoblock and the ordering of a second REX 300 monoblock to match.
Technically, the stereo-to-monoblock conversion is accomplished by paralleling the inputs and outputs.
BAT REX-300 Power Amplifier Features
- Power Supply Filtration: BAT’s new fourth-generation SuperPak topology which provides four levels of power supply filtration
- Power Supply Topology: Uses the same split power supply topology (TWIN-Path) found in the larger REX 500.
- No Fuses: “Fuse-less” protection circuit for enhanced sound and user-friendly operation.
- Gain Stages: There are only two gain stages with Zero Global Feedback and the circuit is fully balanced from input to output.
- MOSFET: The amplifier circuit is based entirely on N-Channel MOSFET devices
- Intelligent Power Upgrade: The REX 300 can be ordered as either a stereo amplifier or as a monoblock
- Power Output (stereo configuration): 200W/ch @ 8 ohms and 400W/ch @ 4 ohms
- Frequency Response: 3Hz to 200kHz
- Nominal Gain 8Ω: 25dB
- Dimensions (WHD): 19 x 6.5 x 18-inches
- Weight: 70 lbs
BAT VK-85 Preamplifier
The VK-85 Preamplifier is the result of a new design strategy that benefits from several improved in-house circuit technologies, including “SuperPak Quattro” and the “Second Generation Transformer Coupled Outputs”, as well as proven BAT circuits such as Unistage Design, High-Current N-Channel MOSFET Circuit, and Shunt Volume Control.
The VLK-85 employs a stage gain design. BAT sees this as a way to free the preamp 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 simplicity of amplifying the incoming signal just once while using no global feedback to double back on the integrity of that signal. This continues to be a hallmark of BAT’s purist approach to circuit topology.
The VK-85 circuit uses the same High-Current N-Channel MOSFET devices just as used with the REX 300. The highly accurate volume control employs a proprietary electronic shunt volume attenuator with 140 steps of 0.5dB resolution. This is accomplished using a single Vishay bulk foil resistor – the most precise and thermally stable resistor available – per phase; This is all that’s in the signal path. Discrete metal film resistors are used to bleed the unused signal to the ground. The 140 steps give precise repeatable volume settings that sound continuous to the human ear.
For added convenience and compatibility with source components, the VK-85 incorporates a mix of balanced and single-ended inputs and outputs.
BAT VK-85 Preamplifier Features
- Core Design: Fully balanced circuit topology
- Power Supply: The revised power supply incorporates BAT’s new fourth-generation SuperPak topology
- Transformer Output: Second-Generation Transformer-Coupled Outputs
- Unistage: Unistage Design with a single gain stage
- MOSFET: High-Current N-Channel MOSFET Circuit
- Noise (unweighted): -96dB / THD @ 2V output: 0.01%
- Inputs: 3 x XLR and 2 x RCAs
- Outputs: “Main” 2 x XLR and “Tape Out” 1 x RCA
- Volume Control: Proprietary electronic shunt volume attenuator with 140 steps of 0.5dB increments.
- Frequency Response: 2Hz to 200kHz
- Maximum Gain: 20dB
- Dimensions (WHD): 19 x 5.75 x 15.5-inches
- Weight: 40 lbs
Balance Circuit Importance for VK-85 and REX 300
The VK-8, REX 300, and all prior BAT preamp and amp models over the past 30 years use balanced circuits. BAT believes a balanced circuit design provides better results because it supports a complete signal representation.
Something very magical occurs when the limitations of a single-ended circuit with its half-signal processing are lifted from an audio component and replaced by a balanced circuit topology.
Aside from the well-established benefits of signal integrity for long interconnect cable runs there are other benefits to balanced circuitry: As a circuit becomes more symmetrical, the residual effect of the power supply becomes less intrusive – the demand on a power supply becomes less taxing.
Pricing & Availability
The BAT VK-85 Preamplifier will be available through authorized dealers in Q2, 2024 with an MSRP of $12,500 (USD).
The BAT REX 300 Power Amplifier will be available through authorized dealers in Q2, 2024 with an MSRP of $15,000 (USD).
Tip: Both models will be on display at AXPONA 2024 – Suite 348, April 12 – 14.
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