Further development of a reference

The Linear USB II continues and systematically develops the Linear series, which was established in 2004. It is based on a completely revised analog board using low-Z copper technology, which optimizes the signal flow and enables particularly artifact-free reproduction. This constructive basis ensures that even complex musical passages remain clearly defined and their internal structure is clearly comprehensible.

Digital integration without compromising sound

With the integrated USB D/A converter, the Linear USB II opens up to the digital music world. Audio data from PCs, Macs or mobile devices are processed directly, without the need for additional external components. The converter works with high sampling rates and resolutions and integrates seamlessly into the analog signal architecture. As a result, timbres, dynamics and spatial representation are fully preserved even with digital playback.

Intelligent automation for everyday use

The Linear USB II automatically detects an incoming USB audio data stream and prioritizes this input independently. As soon as no digital signal is present, the device automatically switches to the analog input. This automatic signal routing eliminates the need for an input selector switch and ensures particularly convenient operation in daily use.

Sovereign control over headphones and loudspeakers

The discrete Class A output stage provides sufficient power reserves to drive even demanding dynamic headphones with control. At the same time, the Linear USB II is able to effortlessly drive long cable runs as a preamplifier and supply active loudspeakers with high precision. The combination of headphone and preamplifier functions makes it a versatile center for compact high-end setups.

Mechanical tranquility as an acoustic factor

Consistent mechanical decoupling also contributes to the acoustic performance. The SSC absorber feet reduce disruptive vibrations from the surroundings and create a quiet working environment for the electronics.

Technical Data

Analog Section

• Input Impedance: 47 kOhm
• Maximum Gain: +0 dB, +10 dB, +18 dB, +20 dB (selectable via DIP switch )
• Frequency Response: 10 Hz (−0.3 dB) to 35 kHz (−1 dB)
• Signal-to-Noise Ratio: > 100 dB at Gain 0 dB
• THD: < 0.001 % at 6 mW / 300 Ohm
• Channel Separation: > 80 dB / 10 kHz
• Output Power:
  • 400 mW / 60 Ohm
  • 200 mW / 300 Ohm
• Output Impedance:
  • Line Out: 50 Ohm
  • Headphone Output: 5 Ohm
• Connections:
  • 2 × Neutrik Headphone Jacks (gold-plated)
  • 1 × Switched Line Out
  • 1 × Unswitched Line Out
  • Gold-plated RCA jacks with Teflon insulation

Digital-to-Analog Converter

• Digital Input: 1 × USB B
• Sampling Rates: up to 384 kHz
• Resolution: up to 32 Bit
• Formats: PCM, DOP, FLAC, MP3, WAV
• Chipset: ESS Sabre K2M
• Analog Filter: Silver Mica Capacitors
• Max. DAC Output Level: 1.8 V RMS
• Special Function: automatic switching to analog input if digital signal is absent

General

• Mains Voltage: 240 V AC
• Power Consumption: approx. 15 W
• Housing Dimensions (W × D × H): 110 × 280 × 50 mm
• Weight: 1.5 kg net
• Made in Germany

FAQ

Which headphones can the Linear USB II drive?
The Linear USB II is designed for all common dynamic headphones and offers flexible adaptation to different impedances and efficiencies thanks to selectable gain.

Can I also use the Linear USB II as a preamplifier ?
Yes. Via the Line-Out, the Linear USB II can be connected directly to active loudspeakers or a power amplifier, functioning as a high-quality streaming preamplifier.

How does input selection work?
The USB input is automatically prioritized. If no digital signal is present, the device automatically switches to the analog RCA input.

Is simultaneous operation of two headphones possible?
Yes. Two parallel headphone outputs allow for double listening pleasure without any loss in sound quality.

What are the advantages of Low-Z copper technology?
The Low-Z copper analog board reduces impedances in the signal path and contributes to higher dynamics, better impulse response, and increased sonic precision.

Scope of Delivery

• Linear USB II Headphone Amplifier
• Power Cable
• User Manual
• Safety Instructions

Lehmannaudio Vertriebs GmbH
Waltherstraße 49 - 51, 51069 Cologne, DE
info@lehmannaudio.com
https://www.lehmannaudio.de
0221 29 49 33 20