L1 Dual Monaural Line Preamplifier

L1 Dual Monaural Line Preamplifier

Arguably the most important component on the shelf of any high-end audio system. The preamplifiers job is seemingly simple, delivery faithfully the source signal to the power amplifier with zero colouration and total transparency. The L1 is a pure class-A, analogue line level preamplifier that excels in every respect placing it amongst the finest designs of its type bar one.

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Description

“Nothing strengthens authority so much as silence.” – Leonardo da Vinci

On the face of it, all a line-stage has to do is allow you to select between sources and set the system level. Sounds simple? Yet, not only is the quality and performance of the line-stage an absolutely key factor in determining overall system performance, there are fewer contenders for state-of-the-art line-stage honours than in any other product category. Maybe designing the best possible line-stage isn’t quite so simple after all…

Any great line-stage must possess transparency, ultra-low-noise performance and absolute stability. It must anchor the incoming signals and deliver them onwards, propelled from a firm footing that ensures dynamic and musical authority.

It must pass the source signals in your system, without limitation or disturbance, leaving no trace of itself on their passage. Any great line-stage needs to be the next best thing to sonically and musically invisible, the hi-fi equivalent of effortlessly enacting its own audio super power.

Like all CH Precision products, the L1 uses fully discrete, balanced and complementary design, ultra-short signal paths and exactingly selected components. It is fed from heavily regulated and filtered power supplies, is wide-bandwidth, high slew-rate and DC coupled. But in this critical application, that’s not enough. It’s one thing to eliminate unnecessary components from the signal path and eliminate DC offset at the inputs, but the L1 takes things much, much further than that. Completely separate left and right channel circuit boards prevent crosstalk, while a super sophisticated, software driven R-2R network for each channel employs precision metal-film resistors and allows precise level control in 0.5dB steps with the minimum possible number of components. DC offset is monitored and eliminating not just at the inputs but throughout the volume control ladder and at multiple points throughout the entire circuit. That makes the L1 not just one of the quietest line-stages ever built, it makes it one of the quietest in operation too.

For a company that is renowned for the flexibility and configurable nature of its products, it is ironic that one of our most musically vital components is also our least adaptable. Although the L1 line-stage has an inherently modular topology, it offers only line-level inputs and comes fully loaded as standard. But that doesn’t mean that the L1 isn’t scalable and upgradable, with the option to add a second chassis for true-monaural operation and one or two X1 external power supplies. Of course, the L1 is fully controllable via the CH-Control App, its inputs can be labeled, you can set overall gain as well as individual input offsets and you can even select a DC blocking capacitor on any input if necessary. But at heart, in terms of signal transfer the L1 is as stripped down and purist as it can possibly be. You can hear that in its performance; you will hear it in any system that’s built around an L1, whether in one, two, three or four-box form. As elegant in design as it is sophisticated in operation, as musically commanding as it is unobtrusive, the L1 brings a whole new sense to the motto, “We hide with pride!”

Features

 

Modularity

Three L1 configurations are available:

  • Monaural operation, with 8 inputs
  • Stereo operation, with 8 inputs for each channel
  • Monaural operation, with 16 inputs

Volume control

For each channel two R-2R ladder network in balanced mode control the volume. Tight tolerances high-grade metal film resistors as well as fast switching, distortion-free analogue switches are used to adjust precisely the listening level. Each ladder has the following features:

  • 20bits R-2R ladder network
  • 118dB volume range in 0.5dB steps, from -100dB to +18dB

Analogue Signal Path

Each channel is physically mounted on its own board to ensure the best immunity against crosstalk, and has the following features:

  • Ultra low noise, high bandwidth, high slew rate design
  • Pure class A, fully symmetrical design
  • Fully discrete transistor based circuitry
  • Phase inversion and Mono modes

Power Supply

  • Dedicated discrete regulated linear power supplies
  • Ultra low noise, high accuracy regulation
  • Oversized mains transformer
  • Shunt regulators for critical stages
  • Over-current protection
  • Can be powered from the X1 External Power Supply

Analogue Audio Inputs

  • Four balanced XLR connectors
  • Two single-ended RCA connectors
  • Two high-bandwidth coaxial BNC 50 Ohm connectors

Analogue Audio Outputs

  • Powerful discrete output buffer
  • Two balanced XLR connectors
  • One single-ended RCA connector
  • One high-bandwidth coaxial BNC 50 Ohm connector

Reviews

“The L1 goes calmly about its business, the anchor to which the system’s absolute spatial and temporal stability are tied, the root of its remarkably low noise floor and sudden dynamic response. In many ways it’s the understated star turn that sums up the whole system.” – ROY GREGORY, HI-FI PLUS MAGAZINE (read in full here)

“This exceptional… line-level preamplifier is a contender for Best in Solid-State. A true reference-quality unit…” – ABSOLUTE SOUND, EDITOR’S CHOICE AWARDS 2017 (read in full here)

“Extremely well-articulated and exposed, very neutral, the L1 made for dramatic, at times even scintillating, listening sessions. It brings you closer than ever to the source…” – MARSHALL NACK, POSITIVE FEEDBACK (read in full here)

Rocky Mountain International HiFi Press Awards: ANALOGUE PREAMPLIFIER BEST PRODUCT AWARD (see more here)

Specificatons

Analogue inputs

Inputs type 4x Balanced XLR (8x in extended monaural configuration)
2x Single-Ended RCA (4x in extended monaural configuration)
2x Single-Ended BNC (4x in extended monaural configuration)
Input impedance Balanced (XLR): 100kΩ or 600Ω
Single-Ended (RCA and BNC): 50kΩ or 300Ω
Maximum input level Balanced (XLR): 16V RMS
Single-Ended (RCA and BNC): 8V RMS

Analogue outputs

Frequency response DC – 1MHz
Total Harmonic Distortion + Noise < 0.001%, 1kHz, unity gain
Signal to Noise Ratio 130dB, unity gain and at maximum input level

Volume control

Topology 20bit R-2R resistor ladder network
Range 118dB range in 0.5dB steps, from -100dB to +18dB

General

Display 480×272 pixels, 24bits colour, AMOLED
Mains operation Selectable 100V, 115, 230V AC, 47-63Hz
Fuses value and location Standby fuse (black holder): 250mA T (230V AC), 500mA T (100V AC, 115V AC)
Main fuse (white holder): 1.6A T (230V AC), 3.15A T (100V AC, 115V AC)
Power supply consumption <1W (standby), 100W max in operation
Dimensions/Weight 440 x 440 x 133mm (W x D x H), 20kg
Remote control IR remote control provided, RC5 codes
Ethernet based system control via the Android CH Control App

Download

User Manual
Manufacturer Website

 

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