Heritage Audio 6673 Module

Introduction

Thank you for choosing the 6673 Module. Heritage Audio is dedicated to bringing you 'the sound of yesterday for tomorrow'. The 6673 is designed to capture that unique, enticing sound. It addresses the yearning for classic vibe, often sought in vintage equipment which can be in questionable operational states and prohibitively expensive. This new module offers reliable, heavy-duty use for years of music making.

Peter Rodriguez
CEO, Heritage Audio - Madrid, Spain

© 2023 Heritage Audio S.L. All rights reserved. Information and drawings are copyrighted and may not be copied or disclosed without written permission. Heritage Audio reserves the right to alter specifications without notice. While checked for accuracy, no liability is assumed for inaccuracies, errors, or omissions.

Description

A Great 80 Series Tool for Ultimate Control

The Heritage Audio 6673 module is a unique design engineered to fit input module slots in vintage 80 Series sound mixing consoles. It is also compatible with Heritage Audio FRAME 8 and RACK 2 powered enclosures, and other equipment following the same mechanical and electrical protocol.

The 6673 Offers Vintage Sound with Modern Flexibility

The 6673 features a Class A Mic preamp with up to 80 dB of gain, suitable for low-output ribbon and dynamic mics. It also includes a Class A line-level amplifier with +10 dB gain and a -20 dB pad for high-level signals. Both the mic preamp and line amplifier utilize separate Carnhill transformers for professional results.

The equalizer is based on the 73-style module but incorporates the 1066 mid-bands. It offers a 4-band EQ with:

• A Baxandall-type high shelf band with a switchable high frequency selector offering 3 options (instead of a fixed 12 kHz).
• Two Mid peak bands (Hi & Low) with 10 selectable frequencies each, plus an 'OFF' position.
• A Baxandall-type Low Shelf band with 4 selectable frequencies for low-end shaping.

Additionally, it includes a Class A High Pass Filter with 3 selectable frequencies (50 Hz, 80 Hz, 300 Hz) to clean up the low end.

The flexibility of the mid-bands is particularly noted for sculpting sounds musically, offering a level of control not typically found in 73-style modules.

Using the Right Components for Desired Sound

Components are carefully selected to match the performance of 1970s units. Custom polystyrene and film capacitors are designed to emulate Siemens styroflex and Mullard Mustard types. Carnhill input transformers are hand-wound in Oxford, UK, exclusively for Heritage Audio, housed in vintage-correct green metal cases. A solid, thick output is ensured by another Carnhill transformer on the fully balanced output. The RACK 2 and FRAME 8 enclosures feature output pots for level control.

The 6673 is handmade and hand-wired by experienced technicians in Madrid, Spain, using 1970s wiring and soldering techniques. Its circuitry is housed on 5 plug-in cards.

Getting Started

Front Panel Controls

The front panel features several controls for shaping your audio:

Rear Panel and Connections

The rear panel features the 80 Series Edge Connector for integration into compatible enclosures.

80 Series Edge Connector Pin Out:

MIC INPUT: Pins 1 (Hi), 2 (Lo), 3 (0V). Impedance switchable between 1200 Ω (default) and 300 Ω (when pressed).

LINE INPUT: Pins 4 (Hi), 5 (Lo), 6 (0V). Available at 0 dBu.

LINK: Pins 7, 8.

Technical Earth Link: Pin 12.

Unbalanced Output: Pins 13 (Hi), 14 (Lo). Available at -3 dBu.

Balanced Output: Pins 15 (Hi), 16 (Lo). Available at 0 dBu.

Power: Pins 17 (+24V), 18 (0V).

Note: The DI input is accessible on the front panel of the RACK 2 enclosure.

Applications

Condenser Microphone

Connect a condenser microphone to MIC INPUT 1 or 2. Activate +48V phantom power via the rack enclosure. Output can be routed to a USB computer or audio interface.

Direct Input (DI)

Connect instruments like guitars or basses to the DI INPUT 1 or 2. Ensure the unit is in the LINE GAIN section to utilize these inputs. Output can be routed to a USB computer or audio interface.

Line Level Input

Connect line-level sources (e.g., keyboards) to the LINE INPUT 1 or 2. Output can be routed to a USB computer or audio interface.

Specifications

• Class A mic preamp with 80 dB of gain and a 4-band EQ.
• Class A line-level amplifier with 10 dB of gain.
• Mid-bands cover nearly the entire audible frequency range.
• Low and high shelving EQs with Baxandall curves.
• Switchable High-Pass Filter: 50 Hz, 80 Hz, and 300 Hz.
• +48V phantom power supplied by the 80 Series chassis.
• Maximum Output: > +26 dBu into 600 Ω.
• THD: < 0.025% at 1 kHz, < 0.05% at 100 Hz.
• Frequency Response: 20 Hz (+0.3 dB) to 20 kHz (-0.2 dB).
• Maximum Gain: Slightly > 80 dB.
• Noise: < -100 dBu.
• Power Consumption: < 110 mA @ 24V DC.
• Dimensions (W x H x L): 45 mm x 224 mm x 304 mm (Standard Series 80 Module).

Signal Flow

The signal path is as follows:

MIC INPUT (LOZ impedance) → CARNHILL TRANSFORMERS → INPUT AMP → EQ → HPF → PHASE → OUTPUT AMP → LINE OUTPUT

LINE INPUT → INPUT AMP → EQ → HPF → PHASE → OUTPUT AMP → LINE OUTPUT

DI Input: Accessible on the front panel of the RACK 2, feeding into the INPUT AMP stage.

Troubleshooting

For further questions, contact: support@heritageaudio.com

Warranty Statement

Limited 2 Year Warranty

Heritage Audio warrants the 6673 Module against defects in materials and workmanship for 2 years from the original purchase date. Defects will be repaired or replaced free of charge upon delivery to Heritage Audio with proof of purchase. The warranty excludes normal wear, abuse, shipping damage, or failure to use the product according to specifications.

Heritage Audio is not liable for damages related to inconvenience, loss of use, time, interrupted operation, or commercial loss.

Heritage Audio and the "H" logo are registered trademarks of Heritage Audio.

Registration

Please visit our website to register your product:

https://heritageaudio.com/registration/

Recall Sheets

The manual includes recall sheets for logging session details, instrument settings, track information, connected equipment, and switch status (ON/OFF) for each module.