Leben RS-28CX Premium Tube Preamplifier
High-End Dual-Chassis Tube Preamplifier With Cr-Type Zero-Feedback Phono Equalization
The Leben RS-28CX is a high-end tube preamplifier designed for serious two-channel audio systems where musicality, transparency and refined analogue performance are essential. Combining a CR-type phono equalizer with a powerful SRPP tube line stage, the RS-28CX is engineered to deliver clear, dynamic and highly natural sound across a wide range of high-end audio systems.
Its dual-chassis architecture separates the power supply from the main audio circuitry, helping protect the sensitive phono equalizer from unwanted interference generated by the power transformer. Carefully selected tubes and high-grade components complete a design focused on preserving the character and quality of the original music signal.
Key Features
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CR-Type Zero-Feedback Phono Equalizer – Uses a carefully engineered CR-type RIAA equalization circuit without negative feedback for natural and highly resolving analogue reproduction.
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GE JAN-Standard 12AT7 Tubes – The phono equalizer is designed around carefully selected General Electric 12AT7 tubes built to J.A.N. standards.
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High-Output SRPP Line Stage – Uses GE 6CG7 dual-triode tubes in a powerful SRPP configuration for strong output capability and excellent amplifier drive.
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Up to 80 V Maximum Output – Designed to drive power amplifiers with low input sensitivity or demanding drive requirements.
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Separate Power Supply Chassis – Keeps the power transformer physically separated from the sensitive main audio circuitry.
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Precision RIAA Equalization – High-grade components help maintain RIAA curve accuracy within less than ±0.3 dB.
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Variable and Fixed Outputs – Provides flexible system integration, including the option to add a subwoofer.
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Five-Step Attenuator – Helps reduce residual noise when paired with high-sensitivity power amplifiers.
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Hand-Built Japanese Construction – Built with carefully selected components and Leben's distinctive tube-audio engineering philosophy.
Cr-Type Zero-Feedback Phono Equalization
The RS-28CX uses a CR-type phono equalization circuit without negative feedback. This design approach requires high gain and places greater importance on tube quality, as the characteristics of the tubes are directly amplified through the circuit.
Leben's CR-type design philosophy focuses on stable high-frequency performance and highly transparent analogue reproduction. The phono stage uses selected GE 12AT7 tubes and high-grade components, with the RIAA curve specified at less than ±0.3 dB.
Powerful Srpp Tube Line Stage
The RS-28CX combines its sophisticated phono stage with a powerful line amplifier using GE 6CG7 dual-triode tubes in an SRPP configuration.
The line stage can deliver up to 80 V of maximum output, giving the RS-28CX the ability to drive power amplifiers with low input sensitivity or limited driving capability.
For systems using high-sensitivity power amplifiers, the five-step attenuator helps reduce residual noise and allows better system matching.
Separate Power Supply Architecture
The RS-28CX uses an independent power supply unit housed in a separate chassis. This design helps isolate the main audio circuitry from possible interference generated by the power transformer.
Separating the power supply from the main preamplifier chassis is particularly beneficial for the sensitive CR-type phono equalizer, supporting Leben's goal of preserving a clean and highly transparent signal path.
Flexible System Integration
The RS-28CX provides both fixed and variable outputs for flexible integration into a wide range of high-end audio systems.
The two-output configuration also supports system expansion, including the addition of a subwoofer where required. The combination of high output capability, flexible attenuation and dual output options allows the RS-28CX to work with a wide variety of power amplifiers and system configurations.
Features
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High-end dual-chassis tube preamplifier.
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CR-type zero-feedback phono equalizer.
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GE 12AT7 tubes for the phono stage.
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GE 6CG7 dual-triode tubes for the line stage.
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SRPP line-stage amplification.
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Maximum output of 80 V through variable and fixed outputs.
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Separate independent power supply chassis.
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Five-step attenuator for system matching.
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High-grade components in critical audio circuits.
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Natural wood side panels.
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30-minute muting function after power-on.
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Hand-built in Japan.
Specifications
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Model: RS-28CX
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Type: Tube Preamplifier with Phono Stage
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Tube Complement: 6CG7 (G.E.) × 2; 12AT7 (G.E.) × 2; 5Y3WGT × 1
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Phono Gain: 20.2 dB
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RIAA Curve: Less than ±0.3 dB
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Maximum Phono Input: 400 mV at 2 kHz
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Line Gain: 25.2 dB
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Maximum Output: 80 V Variable / 80 V Fixed
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Output Impedance: 580 Ω
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Residual Noise: 0.03 mV
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Main Body Weight: 7.0 kg
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Power Supply Weight: 6.5 kg
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Main Body Dimensions: 352 W × 240 D × 175 H mm
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Power Supply Dimensions: 233 W × 240 D × 175 H mm
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Included Accessories: AC Power Cable and Power Supply Connecting Cable
In The Box
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Leben RS-28CX Tube Preamplifier
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Separate Power Supply Unit
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AC Power Cable
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Power Supply Connecting Cable
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Manufacturer's documentation and accessories as supplied
Why Buy From Soundtrails
A high-end preamplifier is the control centre of a serious two-channel system. Phono stage architecture, gain structure, output capability and system matching all play an important role in achieving the best performance from the connected source components and power amplifier.
At SoundTrails, our Audio Video Architects help you design carefully matched high-fidelity systems around your listening preferences, room and equipment. From analogue source integration and preamplifier selection to power amplifier matching, speaker selection and complete two-channel system design, we help ensure that every component works together as part of a balanced and thoughtfully engineered system.
