IGS Audio Tubecore 3U - Vari Mu Tube Mastering Compressor

IGS AUDIO TUBECORE 3U manual

IGS AUDIO TUBECORE Recall Sheet

• Variable-Mu compressor

• Dual-Mono / Mid-Side

• Internal Sidechain-Filter

• IGS Custom Made Audio Transformers

• 24-stage Elma switches

• Attack: 0.1 – 30 ms

• Release: 0.1 – 4 s

• Frequency range: 20Hz to 20kHz +/- 0.2dB

• Operating level: +4dBu

• Max. Input level: +22 dBu

• Max. Output level: +22 dBu

• Dynamic range: >107 dBA (@ 1kHz, +24 dBu)

• Max. Gain: +35dB

• Max. Gain reduction: 20 dB

• SNR: 87 dBA

• THD: 0.12 %

• THD+N: 0.15 %

• IMD (SMPTE): 0.32%

• Crosstalk: 82 dB

What is the IGS Audio Tubecore 3U?

The IGS Audio Tubecore 3U is a two-channel Vari-Mu tube compressor designed for mastering, mixing and stereo-bus processing. It combines a fully balanced, transformer-coupled audio path with stepped controls, dual-mono and Mid/Side operation, sidechain filtering and onboard parallel compression.

Is the IGS Audio Tubecore 3U suitable for mastering?

Yes. The Tubecore 3U is designed as a mastering compressor. Its stepped controls support repeatable settings, while adjustable attack and release, Mid/Side processing, sidechain filtering and a wet/dry mixer provide several ways to control dynamics on a stereo mix.

What type of compressor is the IGS Audio Tubecore 3U?

The Tubecore 3U uses a Vari-Mu design, in which the control voltage changes the operating bias and gain of the compression tubes. It is a tube-based gain-reduction circuit rather than a VCA, FET or optical compressor. The audible result depends on the source, signal level, tube configuration and settings.

Can the IGS Audio Tubecore 3U operate in Mid/Side mode?

Yes. The Tubecore 3U includes active Mid/Side encoding and decoding. The Mid channel represents the sum of the left and right signals, while the Side channel represents their difference. This allows separate compression of these components before they are decoded back into a conventional left/right stereo output.

Does the IGS Audio Tubecore 3U offer parallel compression?

Yes. A stepped wet/dry mixer blends the compressed signal with the uncompressed signal inside the unit. This allows you to combine stronger compression with some of the original dynamics without creating a separate external parallel-compression path.

Does the IGS Audio Tubecore 3U have a sidechain high-pass filter?

Yes. The sidechain high-pass filter offers Off, 60 Hz and 120 Hz settings. It reduces the influence of low-frequency content on the compression detector rather than removing bass from the main audio signal. This can help prevent kick drums or bass-heavy passages from driving more gain reduction than intended.

What attack and release times does the IGS Audio Tubecore 3U offer?

The manufacturer specifies selectable attack times from 0.1 to 30 ms and release times from 0.1 to 4 seconds. Separate attack and release switches let you adjust how quickly compression responds and how it recovers.

What connections and operating levels does the IGS Audio Tubecore 3U use?

The current manufacturer specification lists transformer-balanced XLR inputs and outputs, a 10 kΩ input impedance and a 600 Ω output impedance. The nominal operating level is +4 dBu, with maximum input and output levels of +22 dBu and +26 dBu respectively. Specifications may differ on earlier units.

Which tubes are used in the IGS Audio Tubecore 3U?

IGS Audio lists 6N1P-EW or 6N3P-EW as the standard tube configuration. Manufacturer-listed alternatives include 6BC8, 5670 and 6386. The correct matched tube set and calibration procedure must be selected according to the unit’s documentation; these options should not be treated as unrestricted drop-in replacements.

Can the tubes in the IGS Audio Tubecore 3U be replaced?

Yes. The tubes are accessible from the rear of the unit. The manufacturer’s replacement procedure requires suitable matched tubes and calibration after replacement. Follow the manual and its safety instructions, and have the work performed by a qualified technician if you are not equipped to carry out the procedure safely.

Does the IGS Audio Tubecore 3U have a bypass function?

Yes. The manufacturer’s manual specifies hard-wired bypass. The mode selector includes two bypass positions with the same function, positioned for convenient comparisons when switching between dual-mono and Mid/Side operation.

What rack format and power supply does the IGS Audio Tubecore 3U require?

The Tubecore 3U occupies three rack units in a standard 19-inch rack and requires its dedicated external power supply. The manufacturer specifies 115/230 V AC operation at 50–60 Hz and 44 W power consumption. It is not a 500 Series module.

What warranty is supplied with the IGS Audio Tubecore 3U?

The manufacturer’s manual states a three-year warranty against defects in materials and workmanship, subject to its warranty conditions. Please consult the applicable warranty documentation and retailer terms for coverage, exclusions and return procedures.