The 572 Red Stripe is a tube microphone and instrument preamplifier in API 500 format, designed by IGS Audio on the topology of the Telefunken V72 – one of the most sought-after tube preamplifiers in the history of professional recording. The signal path is fully tube-based: two double-triode valves, JJ ECC803S and JJ ECC81, form a two-stage amplification circuit. The input is transformer-balanced via a Sowter transformer (UK-made); the output runs through an Edcor transformer (USA-made). All front-panel controls are stepped switches throughout – a 41-position gain switch provides precision not available on potentiometers. A backlit analog VU meter with dedicated +48V and CLIP LEDs completes the front panel. Three-year manufacturer warranty.
Second-stage saturation – where the Red Stripe character becomes audible
The 572 Red Stripe operates linearly and transparently at low and moderate gain settings. Its character becomes apparent as the second tube stage enters saturation – harmonic enrichment takes on a distinct tonal quality particularly valued on acoustic guitar, vocals, percussion, and any source that benefits from gentle harmonic compression and a subtle midrange presence lift. The 41-position gain switch (up to 64 dB total) allows precise placement in the saturation zone without the imprecision of a potentiometer. The Hi-Z input (1 MΩ, ¼" TS jack on the front panel) routes guitar or bass directly to the first tube grid without an active buffer stage, giving full access to the tube circuit character from the first stage of amplification.
Interstage pad and HPF – control without bypassing the colour
The –20 dB pad operates between the two amplification stages (interstage) rather than at the module input – meaning it attenuates the signal after it has passed through the Sowter input transformer and the first triode, before reaching the second gain stage. The result is that the colour of the input transformer and first valve is preserved while the level feeding the second stage is controlled. The highpass filter at 6 dB/oct with OFF/50 Hz steps removes low-frequency content without a separate filter module in the chain. Phase reverse switch, +48V phantom power, and a choice between XLR input (rear) and Hi-Z (front panel) complete the feature set. Maximum input level: +16 dBu; maximum output level: +28 dBu; dynamic range: 117 dB; SNR: –100 dBA.
KEY FEATURES
- Tube Mic/Line/Hi-Z preamplifier, API 500 format, mono (1 slot)
- Inspired by the Telefunken V72 topology
- Tubes: JJ ECC803S + JJ ECC81 (two double-triodes)
- Input transformer: Sowter (United Kingdom)
- Output transformer: Edcor (United States)
- 41-position gain switch (up to 64 dB)
- –20 dB interstage pad
- HPF: OFF / 50 Hz (6 dB/oct)
- Hi-Z DI: ¼" TS jack, 1 MΩ (front panel)
- Backlit analog VU meter + dedicated +48V and CLIP LEDs
- Phantom power +48V, polarity reverse switch
- 3-year manufacturer warranty
TECHNICAL SPECIFICATIONS
- Type: tube Mic/Line/Hi-Z preamplifier, API 500, mono
- Slots: 1
- Tubes: 2× double-triode (JJ ECC803S + JJ ECC81)
- Input transformer: Sowter (balanced)
- Output transformer: Edcor (balanced)
- Input impedance: above 1.2 kΩ (balanced)
- Output impedance: 600 Ω (balanced)
- Hi-Z impedance: 1 MΩ
- Gain: up to 64 dB (41 steps)
- Pad: –20 dB (interstage)
- HPF: OFF / 50 Hz (6 dB/oct)
- Maximum input level: +16 dBu
- Maximum output level: +28 dBu
- Dynamic range: 117 dB
- SNR: –100 dBA
- THD+N: max. 0.5%
- Frequency response: 20 Hz – 20 kHz (–1 dB)
- Phantom power: +48V
- Power supply: ±16 V DC
- Power consumption: 6.5 W
- Dimensions: 78×166×229 mm
- Shipping weight: 2 kg
