Total Audio Control COMPRESSOR ONE 500 Series Assembly And User's Manual

ASSEMBLY/USER MANUAL

500 Series

Suite 5, Fairfield, 1048 Govan Road, Glasgow G51 4XS, United Kingdom.

info@totalaudiocontrol.com www.totalaudiocontrol.com

FEW WORDS ON ASSEMBLY

Thank you for purchasing COMPRESSOR ONE in kit form. You will have a lot of fun in building and using it.

Before rushing into building your COMPRESSOR ONE you should study this manual from front to back, and familiarise yourself with the design before starting to solder the first component. As the expression says “one picture tells a thousand words”.

The components are packed and numbered in the correct order. The numbers correspond to the bill of materials. Open them one at a time. Do not open the next package before completing the assembly of the previous one. There is a reason behind each stage.

Populating a PCB always starts with the smallest components. Resistors and/or small signal diodes being the first. If you solder the larger components first you’ll have a hard time in soldering the resistors or the small signal diodes.

Before soldering a component visually check its value and designation. Although normally it is not required testing them would also be a good practice (excluding integrated circuits) before they go on the board. We are extremely lucky to be living at a time when a reasonably well performing digital multimeter with semiconductor testing capability or a capacitance meter can be picked up from ebay for the cost of literally a burger meal. Therefore, investing into a few handheld meters would pay dividends in the long run.

A good quality soldering iron with a fine tip and a set of hand tools are a must. Plumber’s torch does not have a place in electronics assembly, and component leads are not trimmed using a Black Smith’s pliers. A miniature close cutting side cutter will have to be a part of your tool kit. Equally fixing an M2 screw will not be possible with a screw driver normally used for M10 bolt. A simple spring action desoldering pump will do fine for single sided boards. But for double sided/plated through boards, such as this, a proper (electric motor pump action) de-soldering tool will be essential. However, you do not have to get the ones that require remortgaging your house. There are affordable ones that will also do a good job.

Most faults will arise due to incorrect components being inserted or solder bridges. It is particularly important to closely examine the soldering of components with close pads such as transistors. Therefore, unless you have eagle eyes, checking each solder node with a hand held or table mount magnifier as you go along will be an extremely good practice.

Do not stay on the components with the soldering iron for too long as there can be a possibility of causing damage. You should be able to get in and out of a solder node within few seconds.

Safety first, be extremely careful when trimming component leads as these can easily fly off into your face. Always hold the lead with one hand while trimming it with the other.

In general do not rush. Work methodically and have fun.

Total Audio Control August 2019

BLOCK DIAGRAM

SPECIFICATIONS: Measured in Total Audio Control 500 rack.

1) CONTROL RANGES:

Threshold : -30dBu to +20dBu Attack : 100uS to 75ms (Also active in A1 or A2 Recovery mode). Recovery : 75mS to 3S or A1: 50ms/5S or A2: 100mS/2S Ratio : 0 to Limit (>10:1) Gain makeup : -6dB to +18dB Dry/Wet : Fully Dry (Uncompressed) through to fully Wet (Compressed). Sidechain Filter switch : OUT or low pass filters F1 or F2. These can be user defined by jumpers. Optional Sidechain and Dry path insert points. Hard/Soft switch. Feed forward/Feedback switch.

“L” switch providing “Sidechain Listen” facility or multichannel linking. “Master “LED illuminated when a module is the “Master” of a group of modules.

Audio meter range : Signal present to +18dBu Gain Reduction meter range : 1.5dB to 22dB

2) FREQUENCY RESPONSE:

+/- 0.5dB 20Hz to 20 kHz with no compression.

3) NOISE:

Measured true RMS, 20Hz to 20 kHz Compressor OUT: -98dBu Compressor IN (unity gain) -88dBu with THAT4301 VCA. With the BYPASS card option there is no noise contribution when the compressor is switched OUT.

4) THD&N:

Better than 0.05% at 1 kHz and +10dBu input with compressor OUT. With the compressor IN the THD&N is similar with moderate degrees of compression but will increase depending on control settings and signal frequency.

5) MAXIMUM LEVELS:

Supply rails +/-16V Maximum input level: +27dBu Maximum output level (Compressor OUT): +27dBu into 200k load, +25dBu into 600ohm load. Internal operating level -6dB. This is also the level at unbalanced insert points.

6) IMPEDANCES:

Input impedance (balanced): 24k ohms. Output impedance (balanced): 75 ohms. Unbalanced SIDECHAIN insert input impedance: 50k ohms. Unbalanced SIDECHAIN insert output impedance: less than 75 ohms. Unbalanced optional DRY insert input impedance: 50k ohms. Unbalanced option DRY insert output impedance: less than 75 ohms.

7) SLEW RATE:

Compressor OUT better than 7V/uS. Compressor IN - This is determined by the type of VCA used. THAT4301 2V/uS THAT2181A better than 7V/uS.

NOTE: All specifications are nominal and subject to change.