The Ultimate Line Amplifier
The LA4 is identical to the HPA4 except that it eliminates the headphone outputs. The LA4 is well-suited to customers who do not need the headphone amplifier.
The LA4 is a line-level preamplifier that is designed to sit between a reference-quality D/A converter and a reference-quality power amplifier. This is not an easy task. Most hi-fi preamplifiers introduce significant noise and distortion due to the necessity to provide volume control and input switching. To solve this problem, the LA4 is completely relay controlled and features analog amplifiers with vanishingly low distortion. It features relay gain control, relay input selection, and relay muting. The entire system incorporates the finest gold-contact relays available. The gain control has 256 steps in 0.5 dB increments. It also features a relay-controlled balance adjustment. Relay closures are precisely timed to deliver silky-smooth volume changes. No other relay gain control offers this level of precision or performance. The LA4 includes 2 independent 256-step attenuators: one for the left channel and one for the right channel. To make this all happen, the LA4 includes a total of 40 precision relays that switch high-precision metal-film resistors.
100% Analog Signal Path
The LA4 is 100% analog. It is designed to be driven from external D/A converters and external line-level analog sources. The LA4 is designed to drive any professional or hi-fi power amplifier. The LA4 provides the ultimate analog signal path between inputs and outputs. The LA4 eclipses the performance of typical high-end hi-fi preamplifiers by achieving much lower noise and distortion.
System Optimization
At any volume setting, the relay-controlled gain stage provides an optimized attenuator to match the upstream analog source to the downstream power amplifier. This optimization of the gain staging delivers the best possible system SNR for each volume setting. The LA4 will match high-output D/A converters to low-input power amplifiers and vice-versa. It will also provide an optimized interface to and from balanced and unbalanced devices. In addition, it will match high-level professional balanced interfaces to low-level hi-fi balanced interfaces (in either direction).
Speed and Precision
The bandwidth of the LA4 extends from 0.01 Hz to over 500 kHz. This means that the LA4 delivers very precise amplitude and phase accuracy over the entire audio bandwidth. Wave shapes are accurately reproduced, and the entire spectrum is delivered with precise timing. The LA4 will deliver musical overtones with life-like accuracy. This means that musical instruments are rendered without changing their sonic character.
Balanced and Unbalanced I/O
The LA4 features two balanced stereo inputs and two unbalanced stereo inputs. The line amplifier provides one balanced stereo output, one balanced mono sum, and one unbalanced stereo output.
