ADT Toolkit mic preamp

The sonic quality of the high-gain mic preamp (+70dB), +26dBu headroom (under full load), very low noise floor, the high quality dynamic processors, plus almost total control of every available feature, all add together to make the TOOLKIT channel strip a perfect device for the mixing engineer who has all the tools in one box. Additional versatility was added to allow the external keying of the expander/gate and compressor. A balanced insert point was also added to allow insertion of any additional processing device the user might wish to use in combination with the channel strip.

Microphone and Line Pre-Amplifiers and Filters:

There are separate preamplifiers, input and gain controls for microphone and line signals. A front panel switch is used to select between the two. The microphone input of the channel is balanced and floating, and the max. gain is 70 dB. The line input is electronically balanced. Maximum input level for both inputs of the strip is +26 dB. 48V phantom power is available as well as phase reverse and a 20dB pad. The phase reversal switch affects both the microphone and line input signals.

The switched filter section has high-pass and low-pass filters. The high-pass filter has a slope of 24dB/octave and ranges from 20Hz to 600Hz. The low-pass filter has a slope of 12dB/octave and ranges from 25kHz to 1.5kHz. The filter section is fixed post input switch and pre the insert in postition pre EQ.

Compressor:
The compressor is a full featured unit that allows full control of all functions with extensive possibilities for the complex dynamic treatment of all program types. It has variable controls for threshold, ratio, attack, release, and gain, envelope, crest and knee adjustment.

The range of the threshold is from -32dB to 18 dB. The range of the ratio is from 1:1 (inactive) to 1:20 (limit operation). These ranges cover all areas of application, from a soft peak reduction up to the limit operation. The attack range is from 0.1ms up to 30ms and the release range is from 0.05ms up to 3 seconds.

A very unique feature of the channel strip is the Auto Gain/Auto Drive. This feature provides gain make-up to the VCA stage, after the threshold. This ensures that the level of the control signal to the VCA is high and constant. This circuit is separate from the manual make-up gain of the compressor. The compressor can be switched pre or post EQ and has a buffered side chain input and output with a side-chain listen switch that switches the side-chain to the output of the unit.

Noise Gate:

The noise gate circuit is independent of the compressor control circuit and can be switched pre or post EQ independently. The gate is fully featured and allows full control of its functions. All its controls are infinitely adjustable and include; threshold, ratio, attack, release, attenuation depth control and hold.

The two key filters are configured as high-pass and low-pass filters. The sweep range of the low pass filter is from 50Hz to 15kHz; the high pass filter can be regulated from 40 Hz to 8 kHz. The control signal that feeds the gate side chain channel can be band passed with these filters. There is also a buffered and balanced external key input with a front panel, control switch and a side-chain listen switch that sends the gate side-chain signal to the main output of the input strip.

Insert:

The channel strip has one fully balanced switched insert point that is available on 1/4″ TRS connectors on the rear panel. The insert send and return signals can be routed post filters or post EQ by the PRE switch.

Equalizer:

The circuit design of the 5-band equalizer is based on the phase coherent, active Vienna Robinson’s bridge principle. This EQ display an exceptionally high level of audio quality and precision. With its three fully parametric, bands it operates over the frequency range of 20 hertz to 25kHz and allows both aggressive tonal surgery and gentle tone shaping.

Three of the five EQ bands are fully parametric and overlapping, with infinitely adjustable frequency and bandwidth control. The frequency ranges for the separate bands are as follows: MID 1: 20 Hz to 2 kHz, MID 2: 60 Hz to 7 kHz and for MID 3: 250 Hz to 2 5kHz. The adjustable bandwidth has a Q factor range from 3 octaves to a third and the gain range for all 5 bands is from -20dB to +20dB.

The slope of the hi-shelf is max. 6dB/oct – it differs with the dB setting, (at +/-20dB it reaches 6dB/oct). When the 15kHz / 8kHz switch is in the up position the 3dB down / up frequency is 30kHz. When the switch is depressed the band changes to a very soft bell with the centre frequency at 8kHz, also with a slope of 6dB/oct depending on the dB setting.

The low band is in reality a soft bell to avoid an increase in the subsonic range. The centre frequencies are 40Hz and 100Hz, depending on the position of the pushbutton. The 3 dB bandwidth is 3 octaves (very soft).

Limiter:

The limiter a peak-stop limiter, and is separate from the gate and compressor, and therefore has a separate control circuit. The position of the limiter at the end of the signal chain of the unit (just before the output) is fixed. The attack and release times are pre-set and the only control available is the adjustable threshold with a range from -10dB to +20dB. The device is implemented as a look-ahead Limiter with an AC-DC converter as a fast, peak value detector. This limiter is fast reacting, precise and will not allow overshoot. The look-ahead control circuit of the channel strip is VCA controlled for smooth and linear operation.

Output and Connectors:

The channel strip has two main outputs; both outputs receive signal and out 1 is unregulated. The level pot regulates the signal level of out 2, when the pot is switched on. Also, the signal for output 2 can be selected post the filters or post all processing. The signal from output 1 is unregulated and post all processing. The headroom of the outputs is +26dBu with a 600 Ohm load. The two main inputs and outputs are on XLR connectors, and the insert, side-chain and key-input connectors are on 1/4″ TRS connectors.

Power Supply:

Two versions of the external power supply unit TOOLPWR are available. The standard version can supply up to 4 Toolkits. Toolpwr version ‘E’ has a higher capacity and can supply up to 8 channel strip units or other Tool devices.

ADT Toolkit offers the unique combination of :

high-gain, low noise, transformer balanced microphone preamp and an addtional DI Input

versatile Compressor Section with Crest and Envelope Controls

ultra fast Noise-Gate with a complete set of Controls and separate, wide-range Hi-Pass and Low-Pass Filters

super fast Brick-wall Limiter

sophisticated ADT 5 Band Equalizer

24 dB/oct. Hi-Pass Filter and Low-Pass Filter

second Output with Level Control