500 Series – Modular Studio Tools for Flexible Workflows
The 500 Series format has become an integral part of modern studios over the past years. Its modular approach allows preamps, equalizers, compressors, and many other tools to be combined flexibly within a shared system. Flexibility, scalability, and personalized workflow design are at the heart of its appeal.
Rather than relying on fixed equipment configurations, 500 Series systems can be tailored to specific requirements and expanded whenever the need arises.
The question is rarely which module is objectively “the best.” What matters is which combination of functions, signal flow, and sonic character best fits a particular studio and workflow.
Originally derived from classic studio console designs, the 500 Series format has evolved into one of the most flexible standards in professional audio. Today, countless modules from a wide range of manufacturers are available for virtually every stage of the signal chain.
Microphone preamps, equalizers, dynamics processors, saturation stages, effects modules, and specialized tools can all be combined within a shared rack and configured to meet individual needs.
At the same time, the appeal of the 500 Series goes far beyond saving space. The modular concept allows engineers and producers to build signal paths deliberately, expand systems gradually, and combine different sonic characteristics within a single workflow.
In practice, successful setups are rarely defined by individual modules alone. What matters far more is how effectively the various components complement one another and integrate into the overall production process.
That is why you will not find a random collection of modules at Peakhouse Audio. Our selection is based on hands-on studio experience, direct comparisons, and solutions that have proven themselves in professional recording, mixing, and mastering environments.
If you are unsure which modules or rack system best suit your setup, we are happy to help with equipment selection, signal-flow design, and system planning.
Less reliance on fixed systems—and more studio technology that grows alongside your requirements.
ACME Audio XLA500
ACME Audio Opticom XLA-500 – Tube Optical Compressor / Limiter (500-Series) The ACME Audio Opticom XLA-500 brings the sonic architecture of the acclaimed XLA-3 into the compact 500-Series format. This tube-driven optical compressor combines a triple opto compression circuit, a Class-A gain stage and high-quality CineMag transformers, resulting in a highly versatile dynamics processor with strong analog character. Its sound ranges from subtle, musical leveling to aggressive, harmonically rich compression, making it an ideal tool for modern hybrid studios. Sound Character The XLA-500 uses an optical detection circuit combined with tube make-up gain, delivering smooth and musical compression with pleasant harmonic coloration. At the heart of the unit is the Triple Opto Circuit, which blends the characteristics of three different compression curves into one design. This allows compression responses ranging from slow and gentle to fast and aggressive depending on the material. It is especially favored for: ✔ Vocals with rich analog warmth ✔ Drum parallel compression and room microphones ✔ Bass and synth sources requiring weight and density ✔ Guitar tracks with added harmonic richness Highlights ✔ Tube optical compressor / limiter in 500-Series format ✔ Triple Opto Circuit with three compression characteristics ✔ Class-A gain stage ✔ CineMag input and output transformers ✔ Fast / Normal / Slow compression modes ✔ Compression range from subtle to aggressive ✔ True bypass for quick A/B comparison ✔ Dual-slot 500-Series module Typical Studio Applications The XLA-500 is often chosen when engineers want both dynamic control and analog tone coloration. ✔ Lead vocals – dense vintage character ✔ Drum parallel compression – aggressive punch ✔ Bass & synths – enhanced weight and depth ✔ Guitar tracks – additional harmonic texture Technical Specifications ✔ Processor type: Tube optical limiter ✔ Format: API 500-Series (dual-slot module) ✔ Channels: Mono ✔ Gain stage: Class-A tube make-up gain ✔ Transformers: CineMag input & output ✔ Compression modes: Fast / Normal / Slow ✔ Power: ±16 V via 500-Series rack
AEA RPQ500 Preamp
AEA RPQ500 500-Series Microphone Preamp with CurveShaper™ EQ The AEA RPQ500 is a high-end 500-series microphone preamp with an integrated CurveShaper™ equalizer. Based on the acclaimed RPQ series, it is specifically designed for ribbon microphones, while also performing exceptionally well with dynamic and condenser mics. Its extremely high input impedance and discrete JFET circuit provide ultra-clean signal amplification, while the built-in EQ allows for precise and musical tone shaping directly at the preamp stage. As a compact solution for modular 500-series systems, the RPQ500 combines top-tier audio quality with maximum flexibility. Sound Character The RPQ500 delivers an open, natural and highly detailed sound with exceptional clarity. Low-end: deep and controlled Mids: clear and neutral Highs: airy and transparent Its very high input impedance allows ribbon microphones to perform at their full potential without tonal loss. The CurveShaper™ EQ enables precise tonal shaping without compromising the natural sound. Highlights ✔ 500-series microphone preamp (single slot) ✔ integrated CurveShaper™ EQ ✔ optimized for ribbon microphones ✔ ultra-high input impedance (approx. 63 kΩ) ✔ wide gain range (up to approx. 83 dB) ✔ discrete JFET circuit ✔ ultra-low noise and distortion ✔ 2-band shelving EQ (LF & HF, ±20 dB) ✔ continuously variable frequency ranges ✔ switchable high-pass filter ✔ polarity reverse switch ✔ +48 V phantom power Typical Applications ✔ passive ribbon microphones ✔ low-output dynamic microphones ✔ high-end vocal recording ✔ acoustic instruments (guitar, piano, strings) ✔ orchestral and classical recording ✔ premium studio signal chains ✔ 500-series rack systems Technical Specifications ✔ Format: 500-series module (single slot) ✔ Channels: 1 ✔ Gain: up to approx. 83 dB ✔ Input impedance: approx. 63 kΩ ✔ EQ: 2-band shelving (LF: approx. 20 Hz – 1.2 kHz / HF: approx. 1 – 20 kHz) ✔ EQ range: ±20 dB ✔ High-pass filter: variable ✔ Noise: very low (approx. -130 dBu) ✔ THD+N: very low ✔ Max output: approx. +27 dBu ✔ Connectivity: via 500-series rack (XLR) ✔ Power: via 500-series rack
AEA RPQ503
AEA RPQ503 500-Series Microphone Preamp The AEA RPQ503 is a high-end 500-series microphone preamp with integrated EQ, specifically designed for ribbon microphones but equally suitable for dynamic and condenser mics. Based on AEA’s third-generation RPQ circuitry, it combines ultra-high input impedance, extremely clean gain and musical tone shaping directly at the front end of the signal chain, making it ideal for professional recording applications. Sound Character The RPQ503 delivers an open, transparent yet musical sound with excellent detail. Low-end: deep and controlled Mids: clear and natural Highs: open and detailed Its ultra-high input impedance (approx. 68 kΩ) allows ribbon microphones to perform at their full potential without loading effects. The integrated CurveShaper™ EQ provides smooth and musical tone shaping, even with significant adjustments. Highlights ✔ 500-series microphone preamp with integrated EQ ✔ AEA Gen 3 preamp circuitry (RPQ-based) ✔ ultra-high input impedance (approx. 68 kΩ) ✔ wide gain range: approx. 7 – 85 dB ✔ ultra-low noise and distortion ✔ CurveShaper™ EQ (LF/HF shelving, ±20 dB) ✔ continuously variable frequency ranges ✔ mic/line switching ✔ polarity reverse switch ✔ +48 V phantom power Typical Applications ✔ ribbon microphones (optimized impedance matching) ✔ high-end vocal recording ✔ acoustic instruments (guitar, piano, strings) ✔ orchestral and classical recording ✔ low-output sources ✔ premium studio signal chains Technical Specifications ✔ Format: 500-series module (single slot) ✔ Gain: approx. 7 dB – 85 dB ✔ Input impedance: approx. 68 kΩ (phantom off) ✔ EQ: 2-band shelving (LF: approx. 40–675 Hz / HF: approx. 2–28 kHz) ✔ EQ range: ±20 dB ✔ Noise: approx. -130 dBu ✔ THD+N: approx. 0.0018% ✔ Max output: approx. +27 dBu ✔ Power: via 500-series rack ✔ Connectivity: rack-dependent (XLR)
AEA Snaqbox Orange
AEA Snaqbox 2-Slot 500-Series Chassis The AEA Snaqbox is a high-quality compact 2-slot chassis for 500-series modules, designed for maximum signal integrity and flexible routing. It is ideal for desktop setups, portable rigs and minimalist high-end signal chains. Each slot features its own fully isolated power supply with separate linear regulators, effectively reducing noise and crosstalk for ultra-clean performance. Its rugged steel construction combined with transparent or colored acrylic side panels offers both durability and a modern look. Sound Character The Snaqbox is completely transparent and does not color the audio signal. Signal behavior: neutral and clean Noise floor: extremely low due to isolated power design Headroom: depends on installed modules It provides a clean and reliable platform for high-end 500-series gear. Highlights ✔ 2-slot 500-series chassis ✔ compatible with all standard 500-series modules ✔ separate linear regulators per slot for full isolation ✔ external power supply to reduce noise ✔ LINK/CASCADE switch for internal routing ✔ XLR inputs and outputs (Neutrik) ✔ durable steel construction with acrylic side panels ✔ compact desktop form factor ✔ made in the USA Typical Applications ✔ powering 500-series preamps (e.g. RPQ500) ✔ portable recording setups ✔ compact studio rigs ✔ mobile broadcast and live applications ✔ serial processing chains (preamp → EQ → compressor) ✔ high-end desktop signal chains Technical Specifications ✔ Format: 2-slot 500-series chassis ✔ Power per slot: ✔ +16 V / 150 mA ✔ -16 V / 150 mA ✔ +48 V / 13 mA ✔ Routing: LINK/CASCADE switch ✔ Inputs/Outputs: XLR ✔ Power supply: external PSU ✔ Dimensions: approx. 188 × 84 × 150 mm ✔ Weight: approx. 1.0 kg ✔ Design: compact desktop chassis
AEA Snaqbox Transparent
AEA Snaqbox 2-Slot 500-Series Chassis The AEA Snaqbox is a high-quality compact 2-slot chassis for 500-series modules, designed for maximum signal integrity and flexible routing. It is ideal for desktop setups, portable rigs and minimalist high-end signal chains. Each slot features its own fully isolated power supply with separate linear regulators, effectively reducing noise and crosstalk for ultra-clean performance. Its rugged steel construction combined with transparent or colored acrylic side panels offers both durability and a modern look. Sound Character The Snaqbox is completely transparent and does not color the audio signal. Signal behavior: neutral and clean Noise floor: extremely low due to isolated power design Headroom: depends on installed modules It provides a clean and reliable platform for high-end 500-series gear. Highlights ✔ 2-slot 500-series chassis ✔ compatible with all standard 500-series modules ✔ separate linear regulators per slot for full isolation ✔ external power supply to reduce noise ✔ LINK/CASCADE switch for internal routing ✔ XLR inputs and outputs (Neutrik) ✔ durable steel construction with acrylic side panels ✔ compact desktop form factor ✔ made in the USA Typical Applications ✔ powering 500-series preamps (e.g. RPQ500) ✔ portable recording setups ✔ compact studio rigs ✔ mobile broadcast and live applications ✔ serial processing chains (preamp → EQ → compressor) ✔ high-end desktop signal chains Technical Specifications ✔ Format: 2-slot 500-series chassis ✔ Power per slot: ✔ +16 V / 150 mA ✔ -16 V / 150 mA ✔ +48 V / 13 mA ✔ Routing: LINK/CASCADE switch ✔ Inputs/Outputs: XLR ✔ Power supply: external PSU ✔ Dimensions: approx. 188 × 84 × 150 mm ✔ Weight: approx. 1.0 kg ✔ Design: compact desktop chassis
AEA TRP500
AEA TRP500 500-Series Microphone Preamp The AEA TRP500 is a high-end single-channel 500-series microphone preamp from AEA’s third-generation lineup, specifically designed for ribbon microphones. It is based on the original TRP circuit and delivers ultra-high gain, extremely low noise and very high input impedance. With its minimal signal path and discrete JFET design, the TRP500 provides highly transparent and direct signal amplification, making it ideal for professional recording environments. Sound Character The TRP500 delivers an open, natural and slightly musical sound with excellent detail. Low-end: deep, warm and controlled Mids: clear and natural Highs: open and detailed Despite its neutral design, it adds a subtle musical richness that complements ribbon microphones. Its ultra-high input impedance ensures optimal microphone performance without loading effects. Highlights ✔ 500-series microphone preamp (single slot) ✔ optimized for ribbon microphones ✔ ultra-high gain: up to approx. 85 dB ✔ very high input impedance (up to approx. 100 kΩ) ✔ discrete DC-coupled JFET circuit ✔ ultra-low noise and distortion ✔ switchable high-pass filter (115 Hz / 230 Hz) ✔ polarity reverse switch ✔ +48 V phantom power ✔ minimal signal path for maximum transparency Typical Applications ✔ passive ribbon microphones ✔ low-output dynamic microphones ✔ high-end vocal recording ✔ acoustic instruments (guitar, piano, strings) ✔ orchestral and classical recording ✔ premium studio signal chains Technical Specifications ✔ Format: 500-series module (single slot) ✔ Channels: 1 ✔ Gain: up to approx. 85 dB ✔ Input impedance: approx. 66 kΩ – 100 kΩ ✔ Circuit: DC-coupled JFET gain stage ✔ High-pass filter: 115 Hz / 230 Hz (6 dB/octave) ✔ Max output: approx. +28 dBu ✔ Noise: approx. -130 dBu ✔ Connectivity: via 500-series rack (XLR) ✔ Power: via 500-series rack
AMS Neve 1073 LBEQ
AMS Neve 1073 LBEQ The AMS Neve 1073 LBEQ is a compact 500-series mono equalizer that brings the legendary EQ section of the classic Neve 1073 console module into a modern lunchbox format. Designed and manufactured in England, it uses the same discrete Class-A circuitry and inductor-based filter design as the original 1073. The module can operate as a standalone EQ in any 500-series rack or as an insert EQ when paired with the Neve 1073LB microphone preamp, creating a complete classic 1073 signal path. Sound Character The 1073 LBEQ delivers the classic Neve EQ tone with powerful low end, musical midrange and smooth high-frequency presence. Its hand-wound inductor filters reproduce the musical EQ curves that made the original 1073 one of the most sought-after studio processors in recording history. Highlights ✔ classic Neve 1073 EQ in 500-series format ✔ three-band inductor-based EQ ✔ discrete Class-A circuitry ✔ hand-wound inductors for authentic Neve tone ✔ high-pass filter (50 / 80 / 160 / 300 Hz) ✔ ±16 dB high-shelf at 12 kHz ✔ ±18 dB mid band with selectable frequencies ✔ ±16 dB low-shelf EQ ✔ EQ bypass switch ✔ signal presence and clip LED ✔ compatible with all 500-series racks
AMS Neve 1073LB
AMS Neve 1073LB The AMS Neve 1073LB is a classic mono microphone preamp in 500-series format, bringing the legendary sound of the original Neve 1073 console preamp into a compact lunchbox module. The unit uses the same discrete Class-A circuit with transformer-balanced inputs and outputs, delivering the unmistakable Neve tone known for warmth, punch and musical harmonic coloration. “LB” stands for Lunchbox, meaning the module fits into any compatible 500-series rack or API lunchbox system, making it a compact solution for high-end analog front-end recording setups. Sound Character The 1073LB delivers the classic Neve sound with powerful midrange, rich low end and smooth high frequencies. Its transformer-coupled design with Marinair-spec transformers and multiple discrete gain stages provides up to 80 dB of microphone gain, making it suitable for condenser, dynamic and ribbon microphones alike. Highlights ✔ classic Neve 1073 Class-A microphone preamp ✔ 500-series lunchbox format ✔ Marinair transformers for authentic Neve tone ✔ up to 80 dB gain ✔ mic and line inputs ✔ switchable input impedance ✔ 48 V phantom power and polarity reverse ✔ front combo XLR/TRS input ✔ signal presence LED
AMS Neve 88RLB
AMS Neve 88RLB The AMS Neve 88RLB is a premium 500-series mono microphone preamp based on the preamp circuit of the legendary Neve 88RS recording console. It brings the sound and performance of a large-format Neve console into a compact lunchbox module for modern studio setups. The unit features a custom Marinair® transformer-balanced microphone input combined with an electronically balanced output stage, delivering subtle analog warmth while maintaining high transparency and wide bandwidth. Supporting mic, line and DI inputs, the 88RLB provides a versatile recording front-end suitable for microphones, instruments and line-level sources. Sound Character The 88RLB delivers a clean, detailed Neve sound with controlled warmth and excellent headroom. Unlike more colored vintage designs, the 88RS preamp architecture emphasizes clarity and accuracy, while the Marinair transformer adds subtle analog character when desired. The Re-Gen feature allows line and DI signals to pass through the microphone transformer, adding classic Neve tonal coloration when needed. Highlights ✔ mono microphone preamp in 500-series format ✔ derived from the Neve 88RS console preamp ✔ Marinair® transformer-balanced mic input ✔ mic, line and DI inputs ✔ up to +70 dB microphone gain ✔ Re-Gen transformer coloration feature ✔ variable high-pass filter (31.5 – 315 Hz) ✔ intelligent 48V phantom power ✔ -20 dB pad and polarity reverse ✔ front combo XLR/TRS input ✔ compatible with API 500-series racks
AMS Neve RMX16-500
AMS Neve RMX16-500 The AMS Neve RMX16-500 is a high-end digital reverb module in 500-series format, bringing the legendary sound of the original RMX16 from the 1980s into a modern studio workflow. Developed by AMS Neve, it uses the exact same “bit-for-bit” algorithms as the original unit, delivering the iconic sound heard on countless recordings. Originally introduced as one of the first microprocessor-controlled digital reverbs, the RMX16 became a defining tool in music production—especially throughout the 1980s. The 500-series version enhances this legacy with modern DSP, improved noise performance and additional features such as preset storage and wet/dry control. Sound Character The AMS Neve RMX16-500 delivers a rich, dense and musical reverb with a distinctive vintage character. Its most famous feature is the “NonLin” algorithm, which produces the iconic gated reverb sound widely used on 1980s recordings. In addition to classic reverb types (Ambience, Room, Hall, Plate), the unit offers creative effects such as reverse reverb, chorus and delay. It ranges from subtle spatial enhancement to highly characterful effects while always remaining musical and mix-ready. Highlights ✔ classic digital reverb in 500-series format ✔ original RMX16 algorithms (bit-accurate recreation) ✔ iconic 80s gated reverb (NonLin2) ✔ 18 programs including original and expansion algorithms ✔ modern 32-bit DSP with 24-bit / 48 kHz conversion ✔ 100 user preset slots ✔ wet/dry mix control and extended parameter editing ✔ OLED display with intuitive encoder control ✔ significantly lower noise than vintage units ✔ API 500 Series format (3-slot module) Typical Applications ✔ drum and snare reverb (gated / nonlinear) ✔ vocal processing with character ✔ 80s-style effects and retro sound design ✔ mixing and post-production ✔ creative FX (reverse, freeze, modulation) Technical Specifications ✔ device type: digital reverb (500 series module) ✔ DSP: 32-bit processing ✔ converters: 24-bit / 48 kHz ✔ programs: 18 (NonLin, Hall, Plate, Room, Echo, etc.) ✔ presets: 100 user slots ✔ dynamic range: >100 dB ✔ I/O: depends on 500-series rack ✔ format: API 500 Series (3 slots) ✔ configuration: mono-in / stereo-out
API 500-8P Lunchbox
API 500-8P Lunchbox The API 500-8P Lunchbox is a compact 8-slot chassis for API 500-series modules, designed as a portable modular platform for professional recording and mixing systems. The enclosure allows users to install up to eight 500-series modules, enabling custom combinations of microphone preamps, equalizers, compressors and other analog processors. The rack is fully compatible with API 500-series and VPR Alliance-approved modules, providing reliable power and signal routing for a wide range of analog processors. The internal power supply delivers ±16 V rails and +48 V phantom power, ensuring stable operation even with power-hungry modules. Rear-panel DB-25 connectors provide convenient multi-channel connectivity to patchbays or audio interfaces. Additional features include channel-link switches for stereo operation, a rugged steel chassis and a carrying handle for easy transport between studios or remote recording sessions. Highlights ✔ 8-slot rack for API 500-series modules ✔ compatible with VPR Alliance standard modules ✔ 250 mA of power available per slot ✔ internal ±16 V power rails and +48 V phantom power ✔ DB-25 multi-channel I/O connectors ✔ channel link switches for stereo modules ✔ rugged steel chassis with carrying handle ✔ optional rack-mount kit available Technical Specifications ✔ device type: 500-series rack frame / lunchbox ✔ module slots: 8 ✔ power supply: ±16 V DC / +48 V phantom power ✔ power per slot: 250 mA ✔ connectors: DB-25 multi-channel I/O ✔ compatibility: API 500-series / VPR Alliance ✔ mains voltage: 100–250 V AC switchable ✔ form factor: portable desktop chassis (optional rack mount)
API 500VPR
API 500VPR The API 500VPR is a professional 10-slot rack frame for API 500-series modules, designed as the foundation for modular analog outboard systems in recording and mixing studios. The unit allows engineers to install up to ten 500-series modules, enabling customized combinations of microphone preamps, equalizers, compressors and other signal processors. The rack is powered by the included API L200PS tri-polar power supply, delivering ±16 V rails and +48 V phantom power to ensure stable operation for multiple high-performance modules. Each slot provides balanced XLR inputs and outputs on the rear panel, allowing installed modules to be directly integrated into professional analog signal chains. The chassis follows the API VPR Alliance standard, ensuring compatibility with a wide range of 500-series modules from many manufacturers. With its rugged construction and reliable power distribution, the 500VPR is ideal for both permanent studio installations and mobile recording rigs. Highlights ✔ 10-slot rack frame for API 500-series modules ✔ fully compatible with VPR Alliance standard modules ✔ includes API L200PS tri-polar power supply ✔ power rails: ±16 V and +48 V phantom power ✔ balanced XLR inputs and outputs per slot ✔ 19-inch rackmount chassis (3U) ✔ rugged metal construction for professional environments ✔ flexible platform for preamps, EQs, compressors and DI modules Technical Specifications ✔ device type: 500-series rack frame ✔ module slots: 10 ✔ format: 19" rackmount / 3U ✔ power supply: API L200PS tri-polar PSU ✔ supply voltages: ±16 V DC / +48 V DC ✔ I/O: balanced XLR connectors per slot ✔ module format: API 500-series standard (5.25″ × 1.5″) ✔ internal wiring: PIN-2 hot
API 512C
API 512c The API 512c is a legendary discrete microphone, line and instrument preamp in API 500-series format, based directly on the classic API-312 preamp design. It has become one of the most widely used API modules in professional recording studios worldwide. The module uses API’s classic signal architecture with discrete Class-A circuitry, API 2520 op-amp and proprietary transformers, delivering the recognizable API sound with strong transient response, powerful midrange and high headroom. The 512c provides a microphone input, balanced line input and front-panel Hi-Z instrument input, allowing flexible use with microphones, instruments or line-level sources. A dedicated output level control makes it possible to drive the input stage harder for API transformer coloration while controlling final output level. Sound Character The API 512c delivers the classic fast, punchy and direct API preamp sound. Its discrete circuitry responds extremely quickly to transients and produces a clear, powerful signal with strong midrange definition. It is especially popular on drums, vocals, guitars, bass and percussion. Highlights ✔ microphone, line and instrument preamp in API 500-series format ✔ classic API 312 circuit design ✔ discrete Class-A circuit with API 2520 op-amp ✔ proprietary API output transformer ✔ up to 65 dB gain ✔ output level control for variable saturation ✔ front-panel Hi-Z instrument input ✔ 48 V phantom power ✔ 20 dB pad ✔ polarity reverse ✔ peak LED
API 512V
API 512V The API 512V is a professional microphone, line and instrument preamp in standalone rack format, based on the classic API 512c / API 312 circuit design and delivering the legendary API sound in a flexible outboard format. It combines the traditional API discrete signal path with additional gain and output control features for modern recording workflows. At its core is the classic API 2520 op-amp circuit combined with proprietary API transformers, producing the recognizable API sound with fast transient response, punchy midrange and strong headroom. Unlike the 512c, the 512V adds variable output control, allowing engineers to drive the input stage harder for API saturation while independently adjusting output level. The preamp also includes switchable microphone, line and Hi-Z instrument inputs, along with standard studio features such as pad, polarity reverse and phantom power. Sound Character The API 512V delivers the classic fast, direct and punchy API preamp sound. Transients remain precise, mids stay forward and low frequencies sound tight and energetic. It performs exceptionally well on drums, vocals, guitars, bass and synthesizers. Highlights ✔ microphone, line and instrument preamp in standalone rack format ✔ classic API 312 / 512 circuit design ✔ discrete API 2520 op-amp design ✔ proprietary API transformer stage ✔ variable output control for saturation shaping ✔ up to 65 dB gain ✔ front-panel Hi-Z instrument input ✔ 48 V phantom power ✔ 20 dB pad ✔ polarity reverse ✔ peak LED metering ✔ 19-inch rack / 1U
API 525
API 525 The API 525 is a classic discrete compressor/limiter module for the API 500-series format, originally introduced in the early 1970s and now reissued using the original design documents from the API archives. It uses a feedback compression topology, which produces a smoother and more musical response compared with modern feed-forward designs. The module features API’s discrete 2510 and 2520 op-amps with transformer-balanced output, delivering the signature API sound characterized by punchy transients and strong midrange presence. A unique feature is the Ceiling control, which simultaneously adjusts threshold and make-up gain so engineers can change the amount of compression without altering the overall output level. Sound Character The API 525 provides the classic fast, punchy and musical API compression sound. Its feedback design responds naturally to transients, making it ideal for dynamic sources such as drums, guitars and vocals while adding analog character and density. Highlights ✔ classic API 500-series compressor/limiter ✔ faithful reissue of the original 1970s design ✔ feedback compression topology ✔ discrete API 2510 and 2520 op-amps ✔ unique Ceiling control ✔ 2:1 compression / 20:1 limiter mode ✔ integrated de-esser detector filter ✔ four automatic release modes ✔ analog gain-reduction VU meter ✔ hardware relay bypass Technical Specifications ✔ device type: compressor / limiter (500-series) ✔ ratio: 2:1 / 20:1 ✔ attack time: approx. 15 µs ✔ release times: 0.1 – 2 s automatic modes ✔ frequency response: 20 Hz – 40 kHz (±0.5 dB) ✔ max input level: +27 dBu ✔ max output level: +28 dBu ✔ signal-to-noise ratio: approx. 112 dB ✔ format: API 500-series module
API 525A
API 525A The API 525A is a modern discrete FET compressor/limiter for the API 500-series format, based on the classic API 525 compressor originally introduced in the early 1970s. The new model expands the original design with additional control options for greater flexibility in modern studio workflows. Like the original unit, the 525A uses a feedback compression topology, known for its musical response and natural dynamic behavior. The discrete audio path features API 2510 and 2520 op-amps with a proprietary output transformer, delivering the signature API tone with strong midrange punch and excellent transient detail. Compared to the vintage design, the 525A introduces a variable attack control, seven selectable release times, and the classic Ceiling control, which simultaneously adjusts threshold and make-up gain for consistent output levels while changing compression depth. Sound Character The API 525A delivers the classic fast, punchy and musical API compression character. Its FET-based dynamics control responds quickly to transients and can range from subtle dynamic control to aggressive limiting. It is especially effective on drums, guitars, bass and vocals, adding punch and analog density to recordings. Highlights ✔ discrete FET compressor/limiter (500-series module) ✔ based on the classic API 525 compressor ✔ variable attack control (15 µs – 15 ms) ✔ 7 selectable release times ✔ Ceiling control for simultaneous threshold/output adjustment ✔ compression or limiter mode (2:1 / 20:1) ✔ discrete circuit with API 2510 and 2520 op-amps ✔ API transformer-balanced output stage ✔ analog gain-reduction VU meter ✔ hardware bypass Technical Specifications ✔ device type: FET compressor / limiter (500-series) ✔ ratio: 2:1 / 20:1 ✔ attack: 15 µs – 15 ms ✔ release: 0.05 – 2 s (7 modes) ✔ maximum gain reduction: 25 dB ✔ frequency response: 20 Hz – 40 kHz ±0.5 dB ✔ max input level: +27 dBu ✔ max output level: +28 dBu ✔ format: API 500-series module
API 527A
API 527A The API 527A Compressor/Limiter is a versatile VCA compressor/limiter for the API 500-series format, designed for modern recording and mixing workflows while retaining the classic API analog sound. The module belongs to API’s family of VCA-based compressors (including the 225L, 2500 and 529) and features discrete API 2510 and 2520 op-amps with transformer-balanced output, delivering the signature API tone with punchy transients and strong midrange presence. A defining feature is the switchable feed-forward (“NEW”) and feedback (“OLD”) compression topology, allowing engineers to choose between modern precision or vintage-style dynamics behavior. The compressor also includes API’s patented THRUST® sidechain circuit, which reduces low-frequency influence on the detector circuit to maintain a punchy and stable low end during compression. Sound Character The 527A delivers the classic fast, punchy and versatile API compression character. The selectable compression topology allows it to operate as either a transparent modern compressor or a smoother vintage-style dynamics processor. Combined with the THRUST® circuit, it maintains strong low-frequency energy while controlling overall dynamics effectively. Highlights ✔ VCA compressor/limiter for API 500-series racks ✔ switchable feed-forward and feedback compression modes ✔ hard or soft knee compression ✔ THRUST® sidechain filter for enhanced low-end punch ✔ discrete API 2510 / 2520 op-amps ✔ adjustable threshold, ratio, attack, release and output ✔ stereo-link capability ✔ 10-segment LED meter for gain reduction or output level ✔ overload indicator ✔ relay-based hard bypass Technical Specifications ✔ device type: VCA compressor / limiter (500-series module) ✔ ratio: approx. 1.5:1 – ∞:1 ✔ attack: 0.03 ms – 30 ms ✔ release: 50 ms – 3 s ✔ threshold range: -20 dBu to +10 dBu ✔ maximum input level: +26 dBu ✔ maximum output level: +30 dBu ✔ format: API 500-series module (VPR Alliance compatible)
API 529
API 529 The API 529 is a powerful stereo bus compressor for the API 500-series format, bringing many features of the legendary API 2500 compressor into a compact dual-slot module. It is designed for professional mixing and mastering environments where analog bus compression and punch are essential. The compressor uses API’s classic discrete circuitry including 2520 and 2510 op-amps with transformer-balanced output, delivering the signature API sound known for punch, clarity and musical saturation. A key feature is API’s patented THRUST® sidechain circuit, which shapes the detector response to maintain a tight and powerful low end while compressing the rest of the mix more transparently. The Old/New switch allows users to choose between vintage-style feedback compression and modern feed-forward compression, offering different dynamic behaviors and tonal characters. Sound Character The API 529 delivers the classic fast, punchy and musical API compression sound. Its discrete design reacts quickly to transients and works exceptionally well on stereo buses, drum groups and mix processing. The THRUST® circuit helps maintain strong low-frequency energy while keeping the mix tight and controlled. Highlights ✔ stereo bus compressor in API 500-series format ✔ occupies two slots in a 500-series rack ✔ derived from the API 2500 compressor design ✔ discrete 2520 and 2510 op-amps ✔ THRUST® sidechain filter for punchy low end ✔ Old/New compression modes ✔ auto or manual makeup gain ✔ three selectable knee curves ✔ hard-relay bypass ✔ 10-segment LED metering Technical Specifications ✔ device type: stereo VCA compressor (500-series) ✔ format: dual-slot API 500 module ✔ attack time: <1 ms – 50 ms ✔ release time: 0.05 s – 4 s ✔ ratio: 1.5:1 – ∞:1 ✔ threshold: -20 dBu to +10 dBu ✔ frequency response: 20 Hz – 20 kHz (±0.25 dB) ✔ maximum level: +26 dBu input / output ✔ power: +16 V via 500-series rack
API 550A
API 550A The API 550A is a classic 3-band equalizer in API 500-series format, considered one of the most legendary analog EQ modules in recording history. Originally developed for API consoles, it is based on traditional API discrete circuitry and delivers the recognizable API sound with direct control, musicality and exceptional clarity. At the core of the 550A is the classic API 2520 op-amp design, combined with a fully discrete analog signal path. The three EQ bands offer switchable frequency points for fast and intuitive tonal shaping. A defining feature of the 550A is API’s famous proportional-Q circuit: as boost or cut increases, the bandwidth automatically narrows, resulting in highly musical yet precise EQ moves. The high and low bands also provide switchable shelving or peaking behavior, increasing tonal flexibility. Sound Character The API 550A delivers the classic musical, punchy and direct API EQ sound. Midrange remains focused and present, lows stay controlled and highs sound open and natural. Boosts especially retain a very organic character. It performs exceptionally well on vocals, drums, guitars, bass and synthesizers. Highlights ✔ 3-band equalizer in API 500-series format ✔ discrete API 2520 op-amp design ✔ classic proportional-Q circuit ✔ 7 selectable frequencies per band ✔ ±12 dB gain per band ✔ switchable shelving/peaking high and low bands ✔ fast and intuitive operation ✔ highly musical tonal shaping ✔ hard bypass ✔ ideal for recording, mixing and summing
API 550B
API 550B The API 550B is a classic 4-band equalizer in API 500-series format, widely regarded as one of the most iconic analog EQ modules in professional recording studios. It is based on the legendary API discrete circuit design and delivers the recognizable API sound with musicality, punch and exceptional clarity. At the core of the module is the classic API 2520 op-amp design, combined with a fully discrete analog signal path. The four EQ bands feature fixed selectable frequency points for fast and intuitive operation during recording and mixing. A defining feature of the API 550B is its proportional-Q circuit: as boost or cut increases, the filter automatically becomes narrower, resulting in highly musical yet precise tonal shaping. The 550B is equally suited for individual tracks and stereo bus processing and remains one of the most widely used API EQ modules. Sound Character The API 550B delivers the classic musical, punchy and direct API EQ sound. Midrange remains present and focused, lows stay tight and highs sound open and natural. Boosts especially retain a very organic musical character. It performs exceptionally well on vocals, drums, guitars, bass, synthesizers and stereo buses. Highlights ✔ 4-band equalizer in API 500-series format ✔ discrete API 2520 op-amp design ✔ classic proportional-Q circuit ✔ 7 selectable frequencies per band ✔ ±12 dB gain per band ✔ switchable high and low band filter behavior ✔ highly musical tonal shaping ✔ hard bypass ✔ ideal for recording, mixing and summing
API 560
API 560 The API 560 is a classic 10-band graphic equalizer in API 500-series format, widely regarded as one of the most iconic analog EQ modules in professional studio environments. It is based on traditional API circuitry and delivers the recognizable API sound with precision, musicality and immediate hands-on control. At the heart of the API 560 is the legendary API 2520 discrete op-amp, combined with a fully discrete analog signal path. This design provides excellent headroom, clarity and strong analog punch. Its ten fixed frequency bands allow precise control across the full audio spectrum. Each band offers ±12 dB boost and cut, making both subtle corrections and strong tonal shaping possible. The graphic layout allows very fast decision-making during recording, mixing and bus processing. Sound Character The API 560 delivers the classic precise yet musical API EQ character. Adjustments sound direct and controlled without becoming harsh. Midrange shaping is particularly effective, while lows stay tight and highs remain open and detailed. It works exceptionally well on drums, vocals, guitars, bass and stereo buses. Highlights ✔ 10-band graphic equalizer in API 500-series format ✔ discrete API 2520 op-amp design ✔ classic API graphic EQ architecture ✔ ±12 dB boost/cut per band ✔ extremely fast hands-on workflow ✔ musical shaping across the full spectrum ✔ high headroom ✔ hard bypass ✔ ideal for recording, mixing and bus processing
Avedis Audio MA5
Avedis Audio MA5 The MA5 was created to fill the need for a high-quality microphone preamplifier with the characteristic sound of early ‘70s British Class-A consoles. The re-engineering in the creation of the MA5 stemmed from years of experience restoring both American and British modules, deeply rooted in classic transformer-balanced, discrete electronics. Only the best and most suitable components are used throughout, regardless of cost, to attain the best sound. Over a year was spent on the MA5- not only on the engineering side of the design, but also in extensive sound evaluation with observation of specific settings, gain structures, and key components. We have always believed that our ears' sensitivity coupled with experienced judgment of sound is still unparalleled- even with some of the best audio test analyzers which we own and use. In the end, it is our ears we are trying to satisfy. The MA5’s full and open sound is due to a rich harmonic content, particularly in the very low frequencies- even down to, and below, 10Hz. The clear mids and smooth highs come through without sounding dull or smeared. Features: - Standard 500 series modular size 1.5" x 5.25" - Single-ended Class A amplifier - UK-made Carnhill/St Ives input transformer - Custom-designed Jensen output transformer - Stepped-gain rotary switch in 5dB steps - Output level pot for trim and mute - LED-lit pushbuttons - 28kHz feature brings out high frequency detail - Custom-made Marconi-style knobs - High headroom & CMR, low noise design
Avedis Audio MD7
Avedis MD7 Mikrofonvorverstärker - Diskreter Class-A 500er Mic-Preamp mit DI Input/Return, HPF, Phase, 48V - The MD7 addresses the features needed in op-amp based preamps and, more importantly, with a very musical sound without the conventional hard sounding and mid-forward units which are not suitable for today’s digital recordings. The MD7 does not have a PAD and doesn’t need it. The usual place for the PAD in a conventional circuit is before the input transformer and the big reason why we’ve heard over the years that it changes the sound. With the MD7, the full range and dynamic signal hits the Jensen input transformer first, adding it’s own signature to the sound. The MD7’s additional class A amplifier buffers the INPUT TRIM control for even better adjustment of level compared to a fixed PAD of other conventional microphone preamps. We took a long time working on the DI to make it n important part of the MD7’s sound, rather than just an added feature. The input impedance is 10M ohm meaning that you can connect all kinds of instruments, including sensitive high end piezo pickups which require a wide bandwidth and a very high input impedance. If customized level control is needed for the DI circuit, there is a small hole at the side of the unit’s cover which can access a small trim potentiometer. You can adjust the level’s using a small flat head screwdriver. Features: • Gain range from 0dB – 64dB in 4dB steps for recall-ability • Input Trim control for fine control of gain • Utilizes the discrete 1122 op-amp known for depth and resolution • All discrete design with class A buffer amplifier • Wide bandwidth, high headroom, low noise • NO PAD, NO IC’s, and NO Surface Mount Components • Line Input to interface with DAW’s • Phase reverse, and filtered 48V phantom power • High Pass Filter using a gentle slope for natural bass roll-off • 10 Meg-ohm high impedance DI input great for all instrument pickups • SEND feature to run signal through stomp boxes for variety of effects Specifications: • Frequency Response: <10Hz to -3dB at 75kHz • Input Impedance: ≅1500 ohms • Output Impedance: <75 ohms • Common Mode Rejection Ratio: >123dB min @ 60Hz • Maximum Output Level: +28.8 dBu @ 100KΩ, +27.4 dBu @ 600Ω • Power Requirements: ±16 vdc @ 35mA per rail • Gain Voltage: 0 to 22 Volts • Gain dB: 0 to 64.7 dB • Equivalent Input Noise: −114 dBu; Unweighted 300kHz bandwidth • Weight: 2.6 lbs
Black Lion Audio Bluey-500
Black Lion Audio Bluey-500 Black Lion Audio stellt den populären Bluey FET-Kompressor als 500er-Einheit vor. Das kompakte Modul verfügt über alle Funktionen der 19-Zoll-Hardware und macht damit den charakterstarken Klang des Bluey auch im mobilen Lunchbox-Format verfügbar. Auf der Basis des legendären Blue-Stripe-Kompressors, der für Chris Lord-Alge modifiziert wurde, ermöglicht der Bluey 500 effektive Dynamikkontrolle inklusive Mix-Regler. Gleichzeitig liefert er die beliebte Klangfärbung, die Lord-Alge vor allem für Vocals gerne einsetzt, einschließlich des berühmten All-Buttons-Mode für eine besonders intensive Verdichtung des Signals.Funktionen: Der beliebte Black Lion Audio Bluey im 500er Format Auf der Basis einer der Studiolegenden schlechthin Inkl. des berühmten „All-Button-Mode“ Nachbau Chris Lord Alges’s Golden Unit fürs Vocal-Recording 2 Cinemag Transformer Nachbau des original UTC Eingangs-Transformers Nachbau des original Reichenbach Ausgangs-Transformers Dry/Wet-Regler Stereo-Link möglich Lineare Stromversorgung Präzise Kalibrierung Attack stufenlos regelbar von 20uS bis 800uS Release stufenlos regelbar von 50mS to 1200mS Ratio schaltbar 4:1, 8:1, 12:1, 20:1 sowie jede Kombination Handgetestet in den USA Gewicht: 7,17 kg Maße (L x B x H): 19,05 cm x 13,97 cm x 7,62 cm