.bh-wrap, .bh-wrap *, .bh-wrap *::before, .bh-wrap *::after{ box-sizing:border-box; } .bh-wrap{ width:100%; max-width:1100px; margin:0 auto; padding:1rem 1.25rem; line-height:1.6; } .bh-eyebrow{ display:block; margin:0; letter-spacing:.08em; text-transform:uppercase; font-size:.8rem; opacity:.7; } .bh-title{ margin:.25rem 0 1rem; font-size:2.75rem; font-weight:700; line-height:1.2; overflow-wrap:normal; word-break:normal; } .bh-intro{ margin:0 0 1.25rem; font-style:italic; } .bh-grid{ display:grid; grid-template-columns:minmax(0,1fr); gap:2rem; width:100%; max-width:100%; } .bh-main, .bh-side{ display:block; width:100%; min-width:0; max-width:100%; margin:0; padding:0; float:none; } @media(min-width:900px){ .bh-grid{ grid-template-columns:minmax(0,64%) minmax(0,36%); gap:2rem; align-items:start; } } .bh-section{ width:100%; max-width:100%; margin:2rem 0; } .bh-section h2{ margin:0 0 1rem; line-height:1.3; overflow-wrap:normal; word-break:normal; hyphens:none; } .bh-section p, .bh-section li{ overflow-wrap:break-word; word-break:normal; } .bh-bullets{ margin:.5rem 0 0; padding-left:1.25rem; list-style:disc; } .bh-bullets li{ margin-bottom:.45rem; } /* Scroll-free specifications grid */ .bh-specs{ display:block; width:100%; min-width:0; max-width:100%; margin:0; border-top:1px solid #e5e7eb; border-left:1px solid #e5e7eb; overflow:visible; } .bh-spec-row{ display:grid; grid-template-columns:minmax(0,42%) minmax(0,58%); width:100%; min-width:0; } .bh-spec-label, .bh-spec-value{ min-width:0; padding:.58rem; border-right:1px solid #e5e7eb; border-bottom:1px solid #e5e7eb; font-size:.86rem; line-height:1.4; white-space:normal; overflow-wrap:anywhere; word-break:normal; } .bh-spec-label{ background:#f8fafc; font-weight:600; } .bh-faq details{ margin:.5rem 0; padding:.75rem 1rem; border:1px solid #e5e7eb; border-radius:.5rem; background:#fafafa; } .bh-faq summary{ font-weight:600; cursor:pointer; } @media(max-width:899px){ .bh-wrap{ padding:.75rem 1rem; } .bh-title{ font-size:2.1rem; } .bh-grid{ gap:.5rem; } } @media(max-width:480px){ .bh-title{ font-size:1.8rem; } .bh-spec-row{ grid-template-columns:minmax(0,40%) minmax(0,60%); } .bh-spec-label, .bh-spec-value{ padding:.48rem; font-size:.8rem; } } Benchmark Benchmark LA4 Reference Line Amplifier/Preamplifier Fully Balanced Reference Line Preamplifier • 256-Step Relay Volume Control • 0.1Hz–500kHz Bandwidth • XLR & RCA Inputs/Outputs • Home Theater Bypass • Dual 12V Triggers Reference Analog Preamplification with Exceptional Transparency and Precision The Benchmark LA4 Reference Line Amplifier/Preamplifier is a fully balanced analog control preamplifier engineered to introduce exceptionally little noise, distortion or coloration between a source component and power amplifier. Its precision relay-controlled gain system uses high-accuracy resistors and 256 discrete volume settings, allowing repeatable 0.5dB adjustments without the tracking errors and performance limitations associated with conventional analog potentiometers. Two balanced XLR inputs and two stereo RCA inputs accommodate DACs, phono stages, streamers and other analog source components, while balanced XLR, RCA and mono-sum outputs provide extensive system flexibility. Programmable Home Theater Bypass, input-level offsets, balance adjustment, a -20dB Dim function, dual bidirectional 12V triggers and a color touch-screen make the LA4 equally well suited to reference two-channel systems and professional monitoring environments. Highlights & Benefits 256-Step Relay Volume Control — Precision resistor networks provide smooth, repeatable 0.5dB level adjustment with excellent channel matching. Fully Balanced Analog Architecture — Balanced signals remain differential through the input, gain, attenuation and output stages for excellent noise rejection. Ultra-Wide 500kHz Bandwidth — Extended bandwidth supports outstanding phase linearity and fast transient reproduction. Home Theater Bypass — Allows the LA4 to integrate with an AV processor while preserving a dedicated two-channel analog signal path. Flexible System Control — Programmable input offsets, balance control, -20dB Dim, mono summing and dual 12V triggers simplify system integration. Technology & Design High-Precision Relay Attenuator — Twelve relays per output channel select precision resistor networks to create 256 accurate volume positions without placing a conventional potentiometer directly in the signal path. Relay-Controlled Gain Architecture — A 16-step gain stage works together with the attenuation network to maintain excellent signal-to-noise performance over a wide range of playback levels. Fully Balanced Differential Signal Path — The LA4 maintains balanced operation from XLR input through the analog output stages while also supporting conventional RCA source components. Color Touch-Screen & Optical Encoder — A front-panel touch display provides access to programmable settings while the long-life optical volume encoder offers precise tactile control. FAQ — Benchmark LA4 Does the Benchmark LA4 have a built-in DAC? No. The LA4 is a dedicated all-analog line-level preamplifier. Digital sources require a separate DAC with RCA or balanced XLR analog outputs. Does the LA4 include a headphone amplifier? No. The LA4 is optimized specifically for line-level preamplification. Benchmark's HPA4 uses a closely related line-amplifier architecture and adds the THX-888 headphone amplifier. Can the LA4 be used in a home theater system? Yes. The LA4 includes programmable Home Theater Bypass, allowing a compatible AV processor to take control of front-channel volume during surround playback. How precise is the Benchmark LA4 volume control? The LA4 provides 256 relay-controlled volume positions in 0.5dB steps, giving the user highly repeatable control while maintaining excellent left/right channel matching. Why Buy From Us Authorized Benchmark Media Systems Dealer 5% Reward Points on Every Purchase Price Match Guarantee Expert Preamplifier, DAC and High-End Hi-Fi System Advice Related Products & Accessories Benchmark AHB2 Ultra High Resolution Stereo Power Amplifier Benchmark DAC3 B Digital to Analog Audio Converter Benchmark HPA4 Headphone / Line Amplifier Benchmark Studio&Stage StarQuad XLR Cables Benchmark LA4 Specifications Product Type Reference analog line amplifier / stereo preamplifier Signal Path Fully balanced analog Volume Control Relay-controlled precision resistor attenuator Volume Steps 256 Step Size 0.5dB Gain Range Up to +15dB with deep relay attenuation Balanced Inputs 2 × stereo XLR pairs Unbalanced Inputs 2 × stereo RCA pairs Balanced Outputs Left XLR / Right XLR / Mono Sum XLR Unbalanced Outputs Left & Right RCA THD 135dB, 20Hz–20kHz SNR – A-Weighted >137dB Frequency Response -0.003dB at 10Hz-0.001dB at 20kHz -3dB Bandwidth Exceeds 0.1Hz–500kHz Balanced Output Impedance 60 ohms Output Noise
