Tube-Tech HLT 2A

Stereo tube equalizer with tilt filter

The Tube-Tech HLT 2A combines low and high shelves, low-cut and high-cut filters and a tilt-type "T" filter. This is the first time this combination has been offered in analogue. It received a TEC Award in 2016.

The T filter, a tonal seesaw

The T filter pivots the whole spectrum around a centre frequency (500 Hz, 1 kHz or 2 kHz): when the top goes up, the bottom goes down, and vice versa. It is a very quick and very musical way to rebalance a track, a bus or an entire mix. Combined with the shelves, it lets you sculpt the tonal balance in a few moves, with the warmth and depth typical of Tube-Tech tube electronics.

Architecture

The low and high shelves are active, built around a high-gain tube amplifier. The T filter and the low-cut / high-cut filters are passive, placed before the output stage. Each section has its own bypass, in addition to a global bypass. Inputs and outputs are balanced by floating transformers. A mastering version with stepped potentiometers is available: the HLT 2AM.

Specifications

• Low cut: 18, 25, 40, 60, 85 Hz (6 dB/oct)
• Low shelf: 18, 37, 80, 180, 370, 800 Hz, ±12 dB
• High shelf: 1, 2, 5, 10, 15, 22 kHz, ±12 dB
• T filter: 0.5, 1, 2 kHz, +4 / -7 dB
• High cut: 12, 15, 18, 20, 25 kHz (6 dB/oct)
• Frequency response (-3 dB): 5 Hz - 55 kHz
• Noise: < -80 dBu at 0 dB gain
• Channel matching: ±0.3 dB
• Input impedance: > 10 kΩ / output: < 60 Ω
• Push-pull tube amplifier, conductive plastic potentiometers