HLT2A Hi and Lo Shelving EQ with T-Filter

HLT2A description

A totally new kind of analog equalizer that combines variable high and low shelving eq and filters with an adjustable midrange T-Filter.

The midrange T-Filter "tilts" the entire spectrum around a selectable midrange frequency point. Frequencies above that point increase (or decrease) while frequencies below that point decrease (or increase). This unique topology, provides a powerful and uniquely efficient way to get beautiful-sounding overall equalization. As such, the Tube-Tech HLT-2A is destined to become a "go-to" equalizer in high-end mastering houses,smaller project studios, and everything in between.

Like all Tube-Tech processors, the stereo HLT-2A possesses a warmth and character that breathes life into a track and gives it an organic body that somehow manages to occupy real physical space inside a stereo mix,

However, the functionality of the HLT-2A is unique in the Tube-Tech line - and indeed in the world of analog processing. Users will find that the HLT-2A generates quick, intuitive results that can range from mild to extreme, and it sounds great on individual tracks or strapped across the drum bus or the mix bus."

HLT2A Technical Description

TUBE-TECH HLT 2A is a stereo unit, featuring low and high cut filters, low and high shelving filters and a T-filter.

The shelving filters are designed around a high gain tube amplifier.

The T-filter is a passive filter placed between the shelving filters and the output amplifier. All three sections are supplied with a in/out switch. The low and high cut filters are also passive with a slope of 6dB/octave.

A bypass switches the whole filter section out of the amplifier circuit, keeping the output stage in the circuit.

The T-filter is like a seesaw. When the low end goes up, the high end goes down and visa versa.

When the potentiometer is turned clockwise, the high frequencies are boosted and the low frequencies are attenuated.

When the potentiometer is turned counter clockwise, the low frequencies are boosted and the high frequencies are attenuated

The unit is all tube based except for the power supply.

Input and output have fully floating transformers.

All DC voltages are stabilized, except the anode voltage for the output

HLT2A Technical Features

  • Tube based push-pull amplifier
  • Freq. resp. @ -3 dB: 5 Hz - 55 kHz
  • Low noise: < -80 dBU @ 0 dB gain
  • CMRR: > 60 dB @ 10 kHz
  • All-tube active/passive EQ

FILTERS:

  • Low cut: 18, 25, 40, 60, 85 Hz, 6db/octave
  • Low shelving: 18, 37, 80, 180, 370, 800 Hz. Gain: +/?12dB
  • High shelving: 1, 2, 5, 10, 15, 22 kHz Gain: +/?12dB
  • T.-filter: 0,5, 1, 2kHz. Gain: +4/-7 dB
  • High cut: 12, 15, 18, 20, 25 kHz, 6db/octave
  • Tracking between channels: +/-0,3 dB
  • Input impedance: >10 k?
  • Output impedance: < 60?
  • Conductive plastic potentiometers
  • In- and output are transformer balanced and fully floating