Trnovec, Croatia | 2025 – Limestone PP1 Class AB tube amplifier that delivers the warm, rich sound that only a tube amp can provide. Enjoy the sound of true vintage tone.
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Performance
This tube amplifier delivers a rich, full-bodied sound with deep bass and crisp, detailed highs. Its balanced design ensures clear and accurate audio reproduction, offering smooth tonal response across all frequencies.
The output stage features a push-pull design with KT88 tubes. The phase splitter and driver stage use Shuguang Black Treasure CV181-Z tubes, which can be easily swapped with 6SN7 TAD or NOS Sylvania “Bad Boy” upon request.
Craftsmanship
The amplifier showcases a perfect blend of classic craftsmanship and modern design elements. Its chassis is made from 1.5mm stainless steel, ensuring durability and a sleek, polished finish that reflects the timeless elegance of vintage amplifiers.
The exterior is enhanced with Kerrock decorative trims, adding a sophisticated touch while maintaining the ruggedness needed for long-lasting performance.
Modern control
Equipped with microprocessor-controlled power management, the amplifier features delayed high-voltage activation and capacitor discharge during power-down.
A front-panel VU meter and motorized ALPS potentiometer ensure convenient volume control, automatically adjusting during startup and shutdown.
Protection circuitry guards the tubes against bias voltage failures.
Unlimited customization
Every Limestone PP1 is unique, crafted to reflect your personal style. Choose from a range of premium materials and colors, allowing you to customize the amplifier’s finish to suit your aesthetic preferences while maintaining top-tier performance and quality.
Biased towards good music
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The Limestone PP1 features a precise bias control system that ensures optimal performance of the output tubes, delivering consistent and accurate sound quality. Adjusted using a high-precision Simpson analog meter, the bias can be finely tuned to match a variety of tubes, giving you flexibility to customize your audio experience. This meticulous control guarantees that the amplifier operates in its ideal range, extending tube life and ensuring that every note you hear is as pure and powerful as it was meant to be.
Technical specifications
This hand-built tube amplifier delivers exceptional audio performance, combining precision engineering with premium components. Below are the key technical specifications that ensure high-fidelity sound, reliability, and versatility in various audio setups.
Power output: 45W per channel
Frequency response: 30 Hz – 30 kHz (-3dB)
Total Harmonic Distortion (THD): Less than 1% at 1kHz
Input sensitivity: 0.7V RMS for full 45W output
Output Impedance: 4Ω and 8Ω via WBT gold-plated connectors
Noise/Signal Ratio: Approximately 85 dB (noise around 1mV)
Dimensions: 25cm (W) x 25cm (H) x 55cm (D)
Weight: 18 kg
