Heritage Audio 73JR II The Heritage Audio 73JR II is a high-end 500-series microphone preamp that faithfully recreates the legendary sound of classic 1073 console designs in a compact modular format. Designed for professional recording, mixing, and hybrid studio environments, it delivers authentic vintage tone with modern flexibility. Unlike many 500-series implementations, the 73JR II remains true to the original design by featuring a fully discrete three-stage Class-A circuit and an internal 24V power supply—ensuring identical headroom, performance, and saturation behavior to classic console modules. Sound Character The 73JR II delivers the classic “1073 sound”—warm, punchy, and musical. Its three-stage gain architecture provides up to 80 dB of gain, making it suitable for all microphone types, including low-output ribbon microphones. The combination of Class-A circuitry and Carnhill transformers produces rich harmonics, focused mids, and a solid low-end foundation. The result is a bold analog tone that ranges from clean and detailed to richly colored vintage character. Highlights ✔ 500-series microphone preamp in classic 1073 style ✔ fully discrete three-stage Class-A design ✔ true internal 24V power supply for authentic performance ✔ up to 80 dB gain for all microphone types ✔ custom Carnhill input and output transformers ✔ Class-A JFET DI input ✔ 50 dB Class-A line preamp ✔ switchable input impedance (LO-Z) ✔ variable high-pass filter (approx. 20–220 Hz) ✔ pad, phase reverse, and 48 V phantom power ✔ output trim for saturation control ✔ compatible with all 500-series racks Typical Applications ✔ vocal recording with classic console tone ✔ guitar, bass, and DI tracking ✔ drum and instrument recording ✔ reamping and analog coloration ✔ modular 500-series recording setups Technical Specifications ✔ type: single-channel mic/line/DI preamp (500-series) ✔ circuit: discrete Class A (three-stage) ✔ gain: up to >80 dB (mic) ✔ line gain: approx. 50 dB ✔ frequency response: approx. 20 Hz – 20 kHz ✔ THD: < 0.025% @ 1 kHz ✔ noise: approx. -125 dBu EIN ✔ max output: > +26 dBu ✔ input impedance: 1200 / 300 Ω switchable ✔ DI input: > 2 MΩ ✔ I/O: mic/line (XLR), DI (jack) ✔ format: 500-series module

Heritage Audio OST-10 V2.0 The Heritage Audio OST-10 V2.0 is a high-performance 10-slot 500-series rack chassis designed for professional studio and hybrid setups requiring maximum stability, power delivery, and sonic performance. As the largest unit in the OST lineup, it provides maximum capacity for complex modular signal chains. At its core is Heritage Audio’s proprietary On Slot Technology (OST), where each slot features its own individually regulated and isolated power supply. This ensures that even power-hungry Class-A or tube modules operate at peak performance without affecting other modules or introducing noise. Design Concept The OST-10 V2.0 is engineered to deliver the highest possible audio quality in modular 500-series systems. Unlike traditional racks with shared power supplies, each slot operates independently, reducing interference and improving overall system stability. This results in lower noise and better performance—especially for microphone preamps and dynamics processors. The integrated link function allows adjacent channels to be connected instantly via rear-panel switches—no patch cables required. Its large capacity makes it ideal for extensive studio setups and advanced outboard configurations. Highlights ✔ 10-slot chassis for 500-series modules ✔ On Slot Technology (independent power per slot) ✔ reduced noise and optimized module performance ✔ link function for channel pairing without patch cables ✔ compatible with all 500-series modules (including Class-A and tube) ✔ supports double-wide modules ✔ up to 400 mA per slot / 1.8 A total ✔ phantom power up to 140 mA total ✔ status LEDs per slot for voltage monitoring ✔ XLR connections per channel ✔ rugged steel chassis with aluminum front panel ✔ handcrafted in Spain Typical Applications ✔ large-scale 500-series rack systems ✔ complex signal chains (preamp + EQ + compressor) ✔ hybrid mixing and recording setups ✔ mastering and high-end tracking environments ✔ central outboard hub for professional studios Technical Specifications ✔ type: 500-series rack chassis (10 slots) ✔ slots: 10 × 500-series (double-wide supported) ✔ power supply: individually regulated per slot (OST) ✔ current: up to 400 mA per slot / 1.8 A total ✔ phantom power: up to 140 mA total ✔ connections: XLR in/out (DB25 optional depending on version) ✔ voltage: 100–240 V AC ✔ format: 19" rack, 3U ✔ weight: approx. 2.5 kg

Heritage Audio GRANDCHILD 670 The Heritage Audio GRANDCHILD 670 is a high-end stereo Vari-Mu tube compressor in 500-series format, bringing the legendary Fairchild compression sound into a compact and modern design. Built for professional recording, mixing, and mastering environments, it combines iconic vintage tone with practical flexibility. As the “little brother” of the HERCHILD 670, the GRANDCHILD 670 delivers authentic Vari-Mu compression in a space-saving dual-slot module—without compromising sonic quality or musical response. Sound Character The GRANDCHILD 670 delivers classic Vari-Mu compression—smooth, dense, and musical. Its tube-based design provides natural, program-dependent compression with a soft knee and organic response. The result is a creamy, cohesive sound with added warmth, depth, and punch—ideal for bus and mastering applications. Compared to many Vari-Mu compressors, it remains relatively transparent, preserving the original tone while subtly enhancing cohesion and dynamics. Highlights ✔ stereo Vari-Mu tube compressor (500-series format) ✔ based on classic Fairchild / HERCHILD 670 design ✔ true Vari-Mu compression with 4 NOS 6BA6 tubes ✔ 3 custom transformers for authentic tone ✔ 5 selectable attack/release time constants ✔ continuously variable compression slope (DC threshold) ✔ wide range from subtle glue to strong compression ✔ sidechain filtering for low-frequency control ✔ VU meter for gain reduction ✔ true bypass switch ✔ dual-slot 500-series module Typical Applications ✔ mix bus compression (“glue”) ✔ drum bus and parallel compression ✔ mastering with analog character ✔ vocal and instrument processing ✔ high-end hybrid and 500-series studio setups Technical Specifications ✔ type: stereo Vari-Mu tube compressor (500-series module) ✔ circuit: tube-based (4 × NOS 6BA6) ✔ compression: program-dependent Vari-Mu ✔ frequency response: 20 Hz – 20 kHz (±0.5 dB) ✔ max output: +29 dBu ✔ THD: < 0.5% @ +24 dBu ✔ noise: < -78 dBu ✔ input impedance: 15 kΩ ✔ output impedance: 50 Ω ✔ power consumption: >200 mA per rail/slot ✔ format: 500-series, dual slot ✔ weight: approx. 1.12 kg

Heritage Audio OST-4 V2.0 The Heritage Audio OST-4 V2.0 is a compact, high-end 4-slot 500-series rack chassis designed to deliver maximum performance and reliability for modular studio setups. Built for professional recording, mixing, and mobile applications, it provides a powerful and portable platform for demanding 500-series modules. At its core is Heritage Audio’s proprietary On Slot Technology (OST), where each slot features its own individually regulated and isolated power supply. Unlike conventional 500-series racks, this minimizes interference and ensures optimal performance for every module—especially power-hungry Class-A and tube designs. Design Concept The OST-4 V2.0 is engineered to unlock the full sonic potential of 500-series modules. By isolating the power supply of each slot, it prevents modules from affecting each other’s performance, resulting in lower noise, improved stability, and better overall audio quality—particularly for microphone preamps and dynamics processors. The updated V2.0 version introduces a link function, allowing adjacent channels to be connected instantly via rear-panel switches—no patch cables required. Its compact format makes it ideal for portable setups or dedicated signal chains. Highlights ✔ 4-slot chassis for 500-series modules ✔ On Slot Technology (independent power per slot) ✔ reduced noise and improved module performance ✔ link function for channel pairing without patch cables ✔ compatible with all 500-series modules (including Class-A and tube) ✔ supports double-wide modules ✔ up to 400 mA per slot / approx. 1.6–1.8 A total ✔ phantom power up to approx. 140 mA total ✔ XLR connections per slot ✔ rugged steel chassis with aluminum front panel ✔ compact and portable design Typical Applications ✔ compact 500-series racks for studio and mobile use ✔ building vocal or instrument channel strips ✔ hosting preamps, EQs, and compressors ✔ live and touring rigs ✔ entry into modular analog workflows Technical Specifications ✔ type: 500-series rack chassis (4 slots) ✔ slots: 4 × 500-series (double-wide supported) ✔ power supply: individually regulated per slot (OST) ✔ current: up to 400 mA per slot / approx. 1.6–1.8 A total ✔ phantom power: up to approx. 140 mA total ✔ connections: XLR in/out per slot ✔ format: 19" rack (3U) / desktop ✔ weight: approx. 2–2.5 kg ✔ manufacturing: handcrafted in Spain

Heritage Audio OST-8 ADAT The Heritage Audio OST-8 ADAT is a high-end 8-slot 500-series rack chassis with an integrated 8-channel A/D converter, designed to bridge analog processing and digital workflows in modern hybrid studios. At its core is Heritage Audio’s proprietary On Slot Technology (OST), where each slot features an individually regulated and isolated power supply. This minimizes interference and ensures optimal performance for every installed module—even demanding Class-A and tube designs. Design Concept The OST-8 ADAT combines a traditional 500-series chassis with modern digital conversion. Its built-in 8-channel A/D converter (24-bit / 192 kHz) enables direct integration into a DAW via ADAT lightpipe—often requiring just a single optical cable. A standout feature is its flexible routing: each channel can independently send either the direct input signal, the processed signal after the module, or an external source to the converter. This allows highly flexible recording and processing workflows. The integrated link function also allows adjacent modules to be connected internally without patch cables. Highlights ✔ 8-slot chassis for 500-series modules ✔ built-in 8-channel A/D converter (24-bit / 192 kHz) ✔ ADAT lightpipe integration (with S/MUX support) ✔ On Slot Technology (independent power per slot) ✔ up to 400 mA per slot / 1.8 A total ✔ flexible routing options (pre / post / external per channel) ✔ link function for channel pairing without patch cables ✔ word clock input and output ✔ XLR and DB25 analog I/O ✔ compatible with all 500-series modules (including Class-A and tube) ✔ rugged 19" rackmount design (3U) Typical Applications ✔ integrating 500-series modules into DAW workflows ✔ hybrid mixing and recording setups ✔ high-quality A/D conversion for outboard gear ✔ mobile recording rigs with minimal cabling ✔ expanding audio interfaces via ADAT Technical Specifications ✔ type: 500-series rack / 8-channel A/D converter ✔ slots: 8 × 500-series (double-wide supported) ✔ conversion: 24-bit / up to 192 kHz ✔ ADAT: 2 × optical (S/MUX) ✔ word clock: BNC in/out ✔ power: 400 mA per slot / 1.8 A total ✔ phantom power: up to 140 mA total ✔ analog I/O: XLR + DB25 ✔ sample rates: 44.1 – 192 kHz ✔ format: 19" rack, 3U ✔ weight: approx. 4.7 kg

Heritage Audio HABPNL The Heritage Audio HABPNL is a high-quality 500-series blank panel designed for professional rack and modular systems. As an essential accessory for 500-series enclosures, it provides a clean front panel appearance while protecting internal components from dust, debris, and accidental contact. Constructed from durable metal and finished in Heritage Audio’s signature color, the panel integrates seamlessly into existing systems and maintains a consistent, professional studio aesthetic. Function / Design The HABPNL is used to cover unused slots in 500-series rack systems. In addition to improving the visual appearance, it enhances operational safety by protecting sensitive internal electronics from dust and external interference while preventing unwanted access. Pre-drilled mounting holes allow quick and easy installation or removal. Highlights ✔ blank panel for one 500-series slot ✔ protects internal rack components from dust and contact ✔ ensures a clean and professional rack appearance ✔ durable metal construction ✔ compatible with all 500-series racks ✔ pre-drilled mounting holes for easy installation ✔ Heritage Audio signature RAF blue-grey finish Typical Applications ✔ covering unused slots in 500-series racks ✔ protecting sensitive studio equipment ✔ improving rack aesthetics ✔ mobile recording and touring rigs ✔ professional studio installations Technical Specifications ✔ type: 500-series blank panel (single slot) ✔ material: metal ✔ color: RAF blue-grey ✔ dimensions: approx. 3.81 × 13.5 cm ✔ compatibility: all 500-series racks ✔ weight: approx. 45 g