Preamplifiers & Line Stages

The Aavik C-280 is a preamplifier made by Aavik, with separate preamplifier and control-amplifier architecture. It uses an inverted virtual-GND line-stage topology, 72 active Tesla coils, 156 active square Tesla coils, seven dither-circuitry elements, and an optional analog crossover with a 60–160 Hz frequency range. The unit has a natural-based composite cabinet, RCA line output rated at 8.5 Vrms, 50-ohm output impedance, <0.005% THD at 1 kHz and 1 V input, and dimensions of 400 × 384 × 102 mm.

The Aavik C-580, made by Aavik, is a separate control/pre amplifier with line inputs, RCA line output, 76 dB volume control in 1 dB steps, and an optional active analog crossover adjustable from 60–160 Hz. Its line stage uses an inverted virtual-GND amplifier topology, with <0.005% THD, 10 kΩ input impedance, 50 Ω output impedance, and maximum output of 8.5 Vrms. The unit incorporates 108 active Tesla coils, 228 active square Tesla coils, 10 dither-circuitry stages, a switchless optical input board, and a solid-copper inner chassis; it measures 400 × 384 × 102 mm and weighs 8.1 kg.

The Aavik C-880 is a control amplifier manufactured by Aavik. It uses a solid copper enclosure, a copper/heavy compact laminate/titanium sandwich bottom plate, a switchless LDR-based optical input board, an active analog crossover, and resonant-mode power-supply technology; the 880 amplifier design includes four 500 W power-factor-corrected supplies and peak currents exceeding 80 A. Its volume control provides 76 dB in 1 dB steps, and its noise-reduction circuitry comprises 314 active Tesla coils, 633 active square Tesla coils, 36 dither-circuitry units, and two active zirconium anti-aerial-resonance Tesla coils; dimensions are 580 × 510 × 155 mm, with a weight of 35 kg.

The ACCUSTIC ARTS® PREAMP III is a fully balanced reference preamplifier manufactured by ACCUSTIC ARTS® and handmade in Germany. It uses a fully balanced input-to-output circuit, a professional Class A output stage, a four-channel digital volume control, three balanced XLR and three unbalanced RCA inputs including a surround-bypass input, plus balanced and unbalanced outputs and a switchable 1/4-inch headphone output. Construction includes selected components such as Burr Brown® OPA 627 devices, gold-plated relay contacts, a magnetically shielded 50 VA toroidal transformer, an aluminium front panel, cover and remote control, and chromed-brass knobs; specifications include DC–120 kHz frequency response, greater than 102 dB L/R crosstalk attenuation, 11 Veff maximum output voltage, and less than 0.002% THD+N.

The ACCUSTIC ARTS® PREAMP V is a fully balanced reference preamplifier made by ACCUSTIC ARTS® and handmade in Germany. It uses a fully balanced circuit from input to output, a Class A output stage, four-channel digital volume control, three balanced XLR and three unbalanced RCA inputs including a surround-bypass input, and balanced and unbalanced outputs with AC- and DC-coupled options. Its specifications include a DC–120 kHz frequency response, greater than 115 dB crosstalk attenuation, less than 0.001% THD+N, an 11 Veff maximum output voltage, and a magnetically shielded 50 VA toroidal transformer; the front panel and cover are solid aluminium, with chromed brass knobs.

The ACCUSTIC ARTS® TUBE PREAMP III is a fully balanced reference tube preamplifier made by ACCUSTIC ARTS®, using a tube-hybrid topology with four reference tubes, four separate amplification paths, and a Class A output stage. It provides three balanced XLR high-level inputs, three RCA inputs including a surround-bypass input, balanced and unbalanced outputs, a switchable 1/4-inch headphone output, and a 4-channel digital volume control. The unit has a frequency response of DC–50 kHz (+0/−0.5 dB) or DC–120 kHz (+0/−1.5 dB), less than 0.002% THD+N, a crosstalk attenuation greater than 97 dB, and an output voltage of 15 Veff; its front panel and cover are solid aluminum, its knobs are chromed brass, and it uses two magnetically shielded 50 VA toroidal transformers made in Germany.

The ACCUSTIC ARTS® TUBE PREAMP III PHONO is a phono-equipped preamplifier made by Accustic Arts and manufactured by hand in Germany. It uses a tube-hybrid topology with four reference tubes, a fully balanced signal path, four separate amplification paths, a high-end Class A output stage, and a four-channel digital volume control; its frequency response is DC–50 kHz (+0/-0.5 dB) or DC–120 kHz (+0/-1.5 dB), with <0.002% THD+N and >97 dB crosstalk attenuation. The unit provides three balanced XLR and three RCA inputs including surround bypass, balanced and unbalanced outputs, a switchable 1/4-inch headphone output, selectable MM capacitance of 50–425 pF and MC impedance of 47–470 Ω, and uses a solid aluminum front panel and cover, chromed brass knobs, and two encapsulated 50 VA toroidal transformers.

The ACCUSTIC ARTS® TUBE PREAMP V is a fully balanced reference preamplifier made by ACCUSTIC ARTS®, using a “tube hybrid” topology with four reference tubes, four separated amplification paths, and a high-end Class A output stage. It has three balanced XLR and three unbalanced RCA inputs, balanced and unbalanced outputs, a switchable 1/4-inch headphone output, and a four-channel digital volume control. Specifications include a frequency response of DC–50 kHz (+0/-0.5 dB) or DC–120 kHz (+0/-1.5 dB), <0.0015% THD+N, >99 dB crosstalk attenuation, and a maximum output voltage of 18 Veff; its front panel and cover are solid aluminium, and its knobs are chromed brass.

All-tube balanced line stage from Aesthetix's Saturn series using 6922 and 12AX7 tubes with a switched-resistor volume control. Available in standard, Signature and Eclipse versions and long a benchmark at its price.

Allnic Audio is a small South Korean manufacturer, run by designer Kang Su Park, specializing in pure directly-heated-triode (DHT) tube electronics built around vintage and NOS tube types and the company's own Permalloy-core transformers. The L-8000 DHT is the successor to Allnic's L-5000, billed as the world's first commercially produced pure-DHT preamplifier, and is distributed through a small network of specialist dealers rather than mass retail.

The Ansuz Darkz T2 Supreme is a resonance-control device made by Ansuz Acoustics. It consists of three titanium discs, with the upper two discs floating on six titanium interlayer balls—three per disc—for vibration absorption. Each disc has an Ansuz Supreme coating applied by Hi-PIMS, comprising layers of zirconium and tungsten followed by aluminium titanium nitride; dimensions are Ø44.5 × 23.8 mm (1.75 × 0.94 in).

The Ansuz Rack T2 Supreme/Rack is an equipment rack made by Ansuz Acoustics, incorporating Ansuz Darkz T2 Supreme resonance-control devices. Its parts are machined from solid titanium, with four Ansuz Darkz units per shelf; each Darkz consists of three discs, with the upper two floating on three titanium balls. The shelves use natural-based composite NBCM material, and the rack has a mechanical-grounded design; outer dimensions are 793 × 488 mm, with shelf dimensions of 703 × 488 mm and low, medium, and high shelf clearances of 120, 170, and 290 mm.

Aric Audio is a true one-person operation — designer Aric Kimball designs and hand-assembles every unit himself in small batches, sold direct-to-consumer with no retail distribution. The Unlimited II is his mid-line tube preamplifier, and Enjoy the Music.com's world-premiere review called it "extremely quiet" and said it "gives you tremendous value for your money," heartily recommending it.

Cost-no-object reference preamplifier with premium transformer design and 5-page manual

The Audio Research LS28SE is a tube-hybrid line stage preamplifier from the Minnesota-based maker, part of a 50th-anniversary "SE" update line featuring gold-plated coupling capacitors carried over from the flagship Reference 6SE. It replaces the earlier LS28 and carries performance refinements over that model.

SE update of Audio Research's Reference 6 tube line stage with upgraded wiring and capacitors, running six 6H30P triodes plus tube power supply regulation.

The KX-5 Twenty is a solid-state line preamplifier from Colorado-based Ayre Acoustics, recast in 2015 from the original 2013 KX-5 with a Variable-Gain Transconductance volume-control circuit adapted from the flagship KX-R, replacing a traditional attenuating volume control with a variable-gain design intended to keep noise low at any listening level. It uses Ayre's zero-feedback, fully balanced, discrete "Diamond" output stage and was praised by reviewers as one of the quietest preamplifiers they had tested.

The KX-5 Twenty is a solid-state line preamplifier from Colorado-based Ayre Acoustics, recast in 2015 from the original 2013 KX-5 with a Variable-Gain Transconductance volume-control circuit adapted from the flagship KX-R, replacing a traditional attenuating volume control with a variable-gain design intended to keep noise low at any listening level. It uses Ayre's zero-feedback, fully balanced, discrete "Diamond" output stage and was praised by reviewers as one of the quietest preamplifiers they had tested.

The Ayre KX-8 is a variable-gain preamplifier manufactured by Ayre Acoustics, with five analog inputs: two balanced and three single-ended. It uses continuously variable-gain transimpedance volume control, fully balanced zero-feedback discrete circuitry, Ayre’s Diamond output stage, Equilock gain stage, linear analog power supply, and high-speed circuit-board material. Optional digital circuitry includes an ESS ES9038Q2M DAC, Xilinx Spartan FPGA, asynchronous S/PDIF input, custom digital clock, minimum-phase filter, and single-pass 16× oversampling; the unit provides 4 V RMS balanced or 2 V RMS single-ended output and supports variable gain without attenuation.

The Ayre KX-8 is a variable-gain preamplifier manufactured by Ayre Acoustics, with five analog inputs: two balanced and three single-ended. It uses continuously variable-gain transimpedance volume control, fully balanced zero-feedback discrete circuitry, Ayre’s Diamond output stage, Equilock gain stage, linear analog power supply, and high-speed circuit-board material. Optional digital circuitry includes an ESS ES9038Q2M DAC, Xilinx Spartan FPGA, asynchronous S/PDIF input, custom digital clock, minimum-phase filter, and single-pass 16× oversampling; the unit provides 4 V RMS balanced or 2 V RMS single-ended output and supports variable gain without attenuation.

Minimalist two-tube line stage using Backert Labs' patented GreenForce power supply, which removes large electrolytic capacitors from the audio circuit. Runs a pair of 12AU7s and was superseded by the Rhumba 1.4.

Upper-tier version of Backert Labs' Rhumba tube line stage with the company's GreenForce capacitor-based power supply and fully balanced operation. Runs a pair of 12AU7 tubes and was favorably reviewed by The Absolute Sound in 2025.

Fully balanced all-tube line stage using Balanced Audio Technology's single-stage Unistage circuit with no feedback and a high-current output. Features BAT's shielded vishay-based volume attenuator and unified casework shared with the VK-80i.