State of the Art Sonic Excellence, and Operational Flexibility

Line One line level preamplifier

Line One line level preamplifierLine One line level preamplifier rearLine One line level preamplifier front



LKV Research’s Line One preamplifier offers the listener state of the art sonic excellence, and operational flexibility that suits virtually every high end audio system. The Line One reproduces music with natural tones, neutral frequency balance, accurate detail, startling dynamics, and a relaxed, engaging presentation. The bass is deep and tight, the midrange rich and smooth, and the highs extended and airy. The soundstage is wide and deep, with tangible images.

How is this excellence achieved?  An overbuilt power supply with seven stages of regulation and filtering assures clean DC power for the amplifier “gain blocks.”  Those blocks are specially designed differential amplifiers that use hand matched, discrete jfets in Class A, zero feedback configuration to amplify the incoming signals with vanishingly low noise and distortion.  Construction is dual mono with the left and right channels on separate circuit boards.

Premium parts assure the purity of the musical signal is maintained.  A four-gang stepped attenuator using discrete, 0.1% tolerance resistors controls volume.   ELMA switches with gold plated contacts provide input selection.  All resistors are Vishay/Dale metal film 1% tolerance.  All signal path capacitors are WIMA polypropylene.  Four layer circuit boards aid in noise reduction by assuring that signal traces are as short as possible and that all ground connections are made to a ground plain.  Internal signal wires are solid core with Teflon insulation.

Each channel of the Line One has two balanced and four single ended inputs, and two outputs of each type.  Even when using the single ended inputs and/or outputs, all amplification occurs in the differential gain blocks.  Gain can be adjusted to either 4 dB or 10 dB in both single ended and balanced modes.  Front panel controls include mute switches as well as input selectors and volume control.

Features of the LKV Line One preamplifier:

  • Fully differential, class A, zero feedback gain blocks implemented with low-noise jfets.
  • Cascode gain circuitry, stiff current source biasing and hand matched jfets (Idss less than +/- 0.1 mA) to minimize distortion.
  • Two balanced and four single ended inputs for each channel.
  • Two balanced and two single ended outputs for each channel.
  • ELMA stepped attenuator, with 0.1% tolerance resistors, provides volume control.
  • User selectable high (10dB) and low (4 dB) gain settings in both single ended and balanced modes.
  • High current jfet output buffer suitable for driving long cables and low impedances.
  • Straight wire mode, available as extra cost option, allows the music signal to bypass the gain circuitry, passing through only the stepped attenuators and the unity gain output buffer circuit.
  • Separate power supply with custom designed toroidal power transformer and low-noise HEXFRED rectifier diodes.
  • Extensive on-board voltage regulation and filtering assure clean, stable power supply rails for the gain circuitry.
  • Soft start protection to prevent component failure.
  • Dual mono construction with separate circuit boards to reduce crosstalk and enhance imaging.
  • Four layer circuit boards reduce the length of signal and ground traces to minimize noise.
  • Resistors are low-noise Vishay/Dale 1% tolerance metal film.
  • Signal path capacitors are all WIMA polypropylene dielectric.

Enjoy the Music Review and Award for the Line One Preamplifier

Tom Lyle, in his review, emphasized "the LKV Research Line One’s midrange transparency prowess, its very deep and tight bass, extended and sparkling treble, transient speed, its adeptness at creating pin-point images, and [its] crystalline clarity." He summed up by saying "the Line One sounds more like music than a piece of audio equipment. There is no higher praise." Read Full Review

Enjoy the Music also honored the Line One as One of the 20 best of 2014. Read Full Review

Technical Specifications

Main Chassis:
• Width – 17”/Depth – 13”/Height – 4”
• Weight - 9.5 Lbs.

Power Supply:
• Width – 6”/Depth – 13”/Height – 4”
• Weight – 7 Lbs.

Balanced Output with Volume Control at Maximum:
• Gain: 4 dB (Low)/10 dB (High)
• Total Harmonic Distortion (2V out at 1K Hz): 0.003%
• THD + Noise (2V out, 20Hz -20KHz): 0.005%
• Frequency response: +/- 0.15 dB from 20 Hz to 50 KHz
• Signal to Noise Ratio (1V output, 20 to 20KHz): better than 103 dB.
• Crosstalk L-R and R-L (2V output at 2KHz): -115 dB
• Clipping (1% THD) occurs at 19 V output.

Single Ended Output with Volume Control at Maximum:
• Gain: 4 dB (Low)/10 dB (High)
• Total Harmonic Distortion (1V out): 0.01% (Low Gain)/0.008% (High Gain)
• THD + Noise (2V out, 20 Hz – 20K Hz): 0.01%
• Frequency response: +/- 0.15 dB 20 Hz -50 KHz
• Signal to Noise Ratio (1V output, 20 Hz - 20 KHZ): 103 dB.
• Crosstalk L-R and R-L (2V output at 2 KHz): -115 dB.
• Clipping (1% THD) occurs at 9.5 V output.

Fuse:  1.5 Amp ,Fast Acting

*These specifications are subject to revision based on further product testing and development.

Retail Price: $3,500.00

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