TUBECORE
Vari Mu Tube Mastering Compressor
The TUBECORE by IGS Audio is a fully symmetrical, transformer-balanced stereo vari-mu mastering compressor designed for engineers who demand precision with soul. Built in a 3U chassis for clarity and ergonomics, it offers parallel compression, sidechain high-pass filtering, independent attack and release, and dual mono or M/S operation. User-replaceable tubes allow the character to shift from transparent and punchy to deep, dark, or legendary vari-mu weight. Hand-built with premium components and custom transformers, the TUBECORE adds density, depth, and musical dimension with effortless control.
Mastering Compression, Perfected
The TUBECORE by IGS Audio is a no-compromise stereo vari-mu mastering compressor designed for engineers who demand musical authority, dimensional depth, and absolute control. Fully symmetrical and transformer-balanced from input to output, it enhances dynamics without stripping away emotion, adding density, cohesion, and scale in a way that feels natural and effortless.
Rather than imposing a heavy-handed signature, the TUBECORE refines what already exists in the mix. It excels at subtle gain control, delivering polish, width, and harmonic richness that translates seamlessly across mastering, mix bus, and stem processing applications.
Classic Vari-Mu Design, Modern Control
At its core, the TUBECORE is built around a traditional vari-mu topology, elevated with modern mastering features. Alongside classic Input, Threshold, and Output controls, it introduces parallel compression via a dedicated Mix knob, a switchable high-pass filter in the sidechain, and independent Attack and Release switches.
These enhancements allow engineers to retain low-end integrity, preserve transients, and fine-tune dynamic behaviour with precision, making the compressor equally effective for gentle glue or more assertive dynamic shaping.
Designed for Professional Mastering Workflows
Housed in a spacious 3U chassis, the TUBECORE offers excellent front-panel clarity and ergonomic control during critical listening sessions. It supports stereo, dual mono, and Mid/Side operation, providing flexibility for mastering, mix bus work, and detailed stem processing.
The Mode switch includes two identical bypass positions, intentionally implemented to enable fast and intuitive A/B comparisons without interrupting workflow. Every control encourages careful listening rather than constant adjustment.
User-Replaceable Tubes, Tailored Character
A defining feature of the TUBECORE is its user-replaceable tube architecture. Engineers can shape the compressor’s tonal character by selecting from multiple tube types, each offering a distinct response. The standard 6N1P-EW set delivers classic IGS vari-mu compression, while 6BC8 or 6BZ8 tubes provide tighter, more transparent, and punchy behaviour.
For those seeking legendary tone, 6386 tubes offer rich, authoritative compression, while 5670 tubes introduce a deeper, darker harmonic character. Tube access from the rear panel makes experimentation straightforward and safe.
Hand-Built Quality Without Compromise
Every TUBECORE is hand-built using premium, tightly matched components, including 1 percent metal film resistors, Wima capacitors, and custom-designed IGS audio transformers. Each unit is individually calibrated and fitted with NOS tubes to ensure consistency, reliability, and uncompromised sonic performance.
Precision 24-step Elma switches provide accurate recall and repeatability, essential in professional mastering environments where consistency and confidence are paramount.
An Instrument for Serious Engineers
The TUBECORE is more than a mastering compressor. It is a refined analogue instrument designed to enhance depth, control dynamics gracefully, and elevate mixes with unmistakable vari-mu authority. Subtle, powerful, and endlessly musical, it is built for engineers who trust their ears and demand excellence.
Specifications
| Controls | All stepped manipulators, 24-pole Elma switches |
| Processing Modes | Stereo, Dual Mono, Mid/Side (OpAmp M-S encode/decode) |
| Sidechain High-Pass Filter | Off, 60 Hz, 120 Hz |
| Wet / Dry Mix | 0–100%, 4 dB steps |
| Input Impedance Balanced |
XLR, 10 kOhm, IGS custom transformers |
| Output Impedance Balanced |
XLR, 600 Ohm, IGS custom transformers |
| Operating Level | +4 dBu |
| Maximum Input Level | +22 dBu |
| Maximum Output Level | +26 dBu |
| Dynamic Range @ 1 kHz, +24 dBu |
> 107 dBA |
| Maximum Gain Reduction | 20 dB |
| Maximum Gain | +35 dB |
| Attack Time | 0.1 – 30 ms |
| Release Time | 0.1 – 4 s |
| Frequency Response | 20 Hz – 20 kHz ±0.2 dB |
| Signal-to-Noise Ratio @ +4 dBu, 1 kHz |
95 dBA |
| THD | 0.12% |
| THD + Noise | 0.15% |
| IMD SMPTE |
0.32% |
| Crosstalk | 82 dB |
| Power Requirements | 115 / 230 V AC, 50–60 Hz |
| Power Consumption | 44 W |
| Power Supply | External |
| Shipping Dimensions | 70 × 50 × 30 cm |
| Shipping Weight | 9 kg |
| Tube Set |
Standard: 6N1P-EW or 6N3P-EW Optional: 6BC8, 5670, 6386 |
In the interests of product development, IGS Audio reserve the right to modify or improve specifications of this product at any time, without prior notice.