IGS Audio Volf

IGS Audio Volf is a dual-channel stereo Class A FET compressor inspired by the UREI 1176 — the successor to the Volfram with expanded stereo capabilities, switchable transformer/IC input, and an inline Wet/Dry control. Compression is handled by BF245A FET transistors in a matched quad arrangement; both gain stages use discrete IGS 2520 op-amps; UTM Industry transformers are fitted on input and output. Attack range of 20 µs to 1.2 ms and release from 50 ms to 1.2 s match the 1176 topology. All controls run on 24-position Elma switches.

BF245A FET and 1176 Topology — Fast Compression in Stereo

A FET as the gain reduction element defines the 1176 character: near-instantaneous response to transients (attack from 20 µs), wide ratio range, and a tonal character described as punchy, aggressive, and sticky at low attack and short release settings. The Volf implements this topology across two channels with a link option for stereo bus compression with coherent imaging. The IC/UTM Industry transformer input switch selects between a cleaner IC input (less transformer coloration) and the warm, dense character of the transformer path — the difference is most audible at aggressive gain reduction settings. AMP mode bypasses the compression circuit and routes signal through the amplifier stage at 45 dB gain — FET and transformer character without any dynamics control.

Sidechain HPF, Wet/Dry and All Buttons Mode

The sidechain HPF (60/90/120/180/240 Hz or Off) decouples low-frequency content from the compression control — essential on bass and mix bus material with heavy kick drum content, where without HPF the compressor pumps rhythmically in time with the low end. The 24-position Elma Wet/Dry control implements parallel compression inline without external routing or a mix bus. Ratio options include standard 1176 values (4:1, 8:1, 12:1, 20:1) and the All Buttons mode, in which all ratio buttons are engaged simultaneously, producing the aggressive over-compression associated with recordings by Led Zeppelin, Nirvana, and countless others. Maximum gain reduction is 30 dB, maximum gain 45 dB, bandwidth 8 Hz to 22 kHz at ±0.2 dB.

KEY FEATURES

• Dual-channel stereo Class A FET compressor — inspired by UREI 1176
• Compression element: BF245A FET, matched quad
• Discrete IGS 2520 op-amps in both gain stages
• Switchable input: UTM Industry transformers or IC-balanced
• UTM Industry output transformers
• Attack: 20 µs – 1.2 ms (stepped, Elma switch)
• Release: 50 ms – 1.2 s (stepped, Elma switch)
• Ratio: 4:1, 8:1, 12:1, 20:1 + All Buttons mode
• Max gain: 45 dB; max gain reduction: 30 dB
• AMP mode: bypass compression, signal through amplifier at 45 dB
• Sidechain HPF: 60 / 90 / 120 / 180 / 240 Hz / Off (stepped)
• Wet/Dry Mixer — 24-position Elma (inline parallel compression)
• Stereo Link: yes
• All controls stepped — 24-position Elma switches throughout
• Input impedance: 10 kΩ (IC) / UTM Industry transformers (switchable)
• Output impedance: 600 Ω (UTM Industry transformers)
• Max input and output: +18 dBu; operating level: +4 dBu
• Internal linear power supply, 20 W; made in Poland

TECHNICAL SPECIFICATIONS

• Type: dual-channel stereo Class A FET compressor
• Compression element: BF245A FET, matched quad
• Input impedance: 10 kΩ (IC/UTM Industry transformer, switchable)
• Output impedance: 600 Ω (UTM Industry transformers)
• Operating level: +4 dBu
• Max input level: +18 dBu
• Max output level: +18 dBu
• Max gain: 45 dB
• Max gain reduction: 30 dB
• Noise level: 110 dB(A)
• Attack: 20 µs – 1.2 ms
• Release: 50 ms – 1.2 s
• Frequency response: 8 Hz – 22 kHz, ±0.2 dB
• SNR: >84 dB
• THD: 0.12%
• THD+N: 0.19%
• Crosstalk: 80 dB
• Sidechain HPF: 60 / 90 / 120 / 180 / 240 Hz / Off
• Power: internal linear PSU, 20 W
• Made in: Poland