LINEa
Karan Acoustics’ reference two-chassis line preamplifier: fully balanced, active Class A circuitry with no global feedback, relay-controlled volume and a dedicated external power supply. Hand-assembled in Europe.
Key Features
- Reference two-chassis line-level preamplifier
- Fully symmetrical, truly differential and balanced circuit architecture
- Active Class A operation with no global feedback
- DC-coupled signal path without capacitors in the audio-signal route
- Four balanced XLR and two unbalanced RCA inputs
- Two balanced XLR outputs
- Selectable gain of +6 dB or +9 dB
- Four-section balanced relay attenuator with custom non-magnetic resistors
- Remote-controlled volume, mute and absolute-polarity selection
- Separate power supplies and regulation for each audio channel
- Dedicated external power-supply chassis
- Cardas Audio pure-copper internal wiring
- Critical Mass Systems CS2-1.0 isolation feet
- Massive aluminium chassis designed to reduce mechanical, RF and electromagnetic interference
- Five-year parts-and-labour warranty
- Hand-assembled from individually selected and tested components
Design & Build
LINEa separates its audio and power-supply circuitry into two matching enclosures. Its fully complementary, symmetrical and differential topology operates in active Class A without global feedback. The signal path is DC-coupled, with proprietary servo circuits controlling DC offset without placing capacitors directly in the audio path.
Volume is controlled through a four-section balanced attenuator using ultra-fast relays and custom-made, non-magnetic resistors with 0.1% tolerance. Separate transformers, filtration and regulation are provided for the audio channels and control circuitry.
The substantial aluminium chassis helps shield the circuits from radio-frequency and electromagnetic interference. Cardas Audio pure-copper internal wiring and Critical Mass Systems CS2-1.0 isolation feet are fitted as standard.
System Pairing
LINEa is designed as the control centre of a reference analogue system. Its four balanced and two unbalanced inputs accommodate multiple source components, while two balanced outputs can feed a power amplifier and a second amplifier or subwoofer system.
Its 90-ohm output impedance and maximum balanced output of 18 V allow it to drive long interconnects and demanding amplifier inputs. LINEa is the natural preamplifier for Karan’s POWERa and POWERb stereo or monoblock amplifiers.
Technical Specifications
| Specification | Detail |
|---|---|
| Type | Two-chassis fully balanced line preamplifier |
| Circuit topology | Active Class A; fully symmetrical and differential; no global feedback; DC-coupled |
| Line inputs | 4 × balanced XLR; 2 × unbalanced RCA |
| Line outputs | 2 × balanced XLR |
| Input impedance | 30 kilohms, balanced or unbalanced |
| Output impedance | 90 ohms |
| Nominal output level | 1.55 V RMS |
| Maximum output level | 18 V RMS, balanced into a 600-ohm load |
| Maximum input level | 5.4 V RMS at +6 dB gain; 3.6 V RMS at +9 dB gain |
| Gain | +6 dB or +9 dB, adjustable |
| Frequency response | 20 Hz–20 kHz, ±0 dB; 1.5 Hz–3 MHz, –3 dB |
| THD | 0.003% at full output, 20 Hz–20 kHz |
| IMD | 0.003% at full output |
| Rise and settling time | Less than 450 ns |
| Slew rate | 1,500 V/µs through the amplification stages |
| Signal-to-noise ratio | Greater than 120 dB, unweighted |
| Volume control | Four-section fully balanced relay attenuator |
| Additional controls | Mute and absolute-polarity selection |
| Internal wiring | Cardas Audio pure-copper chassis wire |
| Isolation feet | Critical Mass Systems CS2-1.0 |
| Power supply | Dedicated external power-supply chassis |
| AC voltage | 115 V or 230 V nominal |
| AC voltage tolerance | ±10% from nominal voltage |
| Maximum power consumption | 60 W |
| Dimensions (W × H × D) | Main unit: 504 × 141 × 390 mm; power supply: 504 × 141 × 390 mm |
| Weight | Main unit: 16.2 kg; power supply: 17.1 kg |
| Warranty | Five years, parts and labour |
