6. Circuit designs

The electronic circuits of various compressors differ in the design of the operational amplifier, which is responsible for the automatic level adjustments. This would not be worth mentioning, if the type of operational amplifier didn't have an effect on the sound quality and sonic characteristics of the compressor. Below, we would like to give you an overview of the most common designs.

VCA

VCA stands for „Voltage Controlled Amplifier“. The control signal is derived from the input voltage and fed to the VCA in the form of a rectified control voltage. VCAs are readily available as integrated circuits (ICs) from manufacturers like THAT Corp. Their fundamental advantage is their linear frequency response. They also allow for very short response times. Of all designs, these models have the smallest effect on the sonic characteristics of the signal. VCA compressors offer great flexibility and can generally be used for all applications. Some well known VCA compressors include the SSL Bus Compressor, the API 2500, and the DBX 160.
DBX 160A Mono-Compressor

Opto

Opto-compressors are another popular variety. In this design, a photosensitive resistor (Light Dependent Resistor, LDR) or photo transistor is responsible for the signal-dependent amplification. The LDR is illuminated by a suitable light source (bulb or LED), whose brightness is modulated by the input signal. A change of brightness causes a change of resistance of the LDR. Optical compressors typically exhibit a certain sluggishness in their time response. In addition, their response is nonlinear. For enthusiasts, these „imperfections“ account for the unique charm of these devices, and the sonic quality is often perceived as very musical. However, certain applications require faster response times than an opto-compressor can deliver. Famous examples of opto-compressors include the Universal Audio LA-2A and LA-3A.
Universal Audio LA2A Teletronix

Tube / Valve / Variable MU

Today, tubes are added to the signal paths of many compressors, in order to add the popular „tube sound“ to the signal. However, most of these devices still rely on VCAs or optocouplers as their control elements. In a true tube or valve compressor, the control element itself is a tube (pentode). The manner in which the signal is fed to the tube causes a variable, signal-dependent amplification, which is known as Variable MU. These compressors do not have adjustable ratios. The ratio automatically increases with the level of the input signal. The higher the input level, the higher the ratio, and the greater the gain reduction. The tube causes a typical, smooth distortion, which is responsible for the characteristic sound of Variable MU compressors. The time response is typically between that of opto and VCA compressors. The Fairchild models 660 and 670 were designed this way, as is the Manley Variable MU.

Manley Variable MU

FET

Here, the operational amplifier is based on a field-effect transistor (FET). In the working range of the response curve, it functions like a voltage-controlled resistor and mimics the behavior of a tube. Like tube compressors, FET units have unique sonic characteristics. The best known example of this category is the Universal Audio 1176 LN.

Universal Audio 1176 LN

PlugIns

In the age of DAW-based recording studios, compressors are of course readily available as software plug-ins. Virtually all of the analog classics mentioned above have been emulated as software. Well-known producers of high quality emulations include companies like Universal Audio, Waves, SSL, Softube, Slate Digital, and others. In comparison, the compressor plug-ins that come bundled with DAW software tend to be of lesser quality. If the respective hardware units don't fit within your budget, consider high-quality plug-ins by these manufacturers. The audio quality is very close to the originals, with the added bonus of being able to use multiple instances of the plug-ins simultaneously.

Yhteyshenkilösi

Parhaiten arvostellut tuotteet

  1. DBX 286 S

    DBX 286 S

    Varastossa
    138 €
    219 €
  2. FMR Audio RNC 1773

    FMR Audio RNC 1773

    Varastossa
    219 €
  3. DBX 166 XS

    DBX 166 XS

    Varastossa
    144 €
    229 €
  4. TC-Helicon VoiceTone T1

    TC-Helicon Voice­Tone T1

    Varastossa
    85 €
  5. Samson S-Com 4

    Samson S-Com 4

    Varastossa
    126 €
  6. FMR Audio RNLA 7239

    FMR Audio RNLA 7239

    Varastossa
    259 €
  7. DBX 266 XS

    DBX 266 XS

    Varastossa
    117 €
    139 €
  8. DBX 160A

    DBX 160A

    Varastossa
    498 €
    599 €
  9. Klark Teknik 76-KT

    Klark Teknik 76-KT

    Varastossa
    205 €
  10. ART Pro VLA II

    ART Pro VLA II

    Varastossa
    429 €
    545 €
  11. Waves Gold

    Waves Gold

    Ladattava lisenssi
    299 €
  12. Warm Audio WA76

    Warm Audio WA76

    Varastossa
    555 €
    649 €
  13. Softube Console 1 Mk 2

    Sof­tube Con­sole 1 Mk 2

    Varastossa
    389 €
    495 €
  14. Klark Teknik KT-2A

    Klark Teknik KT-2A

    Varastossa
    333 €
  15. ART Tube MP/C

    ART Tube MP/​C

    Varastossa
    139 €
    265 €

Suositut tuotemerkit

  • Chandler Limited
  • Tube-Tech
  • Rupert Neve Designs
  • Tegeler Audio Manufaktur
  • Empirical Labs
  • Eventide
  • the box pro
  • IK Multimedia
  • Drawmer
  • IGS Audio
  • Positive Grid
  • Celemony

Suosituimmat tuotteet

  1. Klark Teknik 76-KT

    Klark Teknik 76-KT

    Varastossa
    205 €
  2. DBX 286 S

    DBX 286 S

    Varastossa
    138 €
    219 €
  3. Klark Teknik KT-2A

    Klark Teknik KT-2A

    Varastossa
    333 €
  4. tc electronic DVR250-DT

    tc elect­ronic DVR250-DT

    Varastossa
    218 €
  5. DBX 166 XS

    DBX 166 XS

    Varastossa
    144 €
    229 €
  6. Softube Console 1 Mk 2

    Sof­tube Con­sole 1 Mk 2

    Varastossa
    389 €
    495 €
  7. tc electronic TC1210-DT

    tc elect­ronic TC1210-DT

    Varastossa
    149 €
  8. Drawmer SP2120

    Drawmer SP2120

    Varastossa
    535 €
    737 €
  9. the t.racks DSP 306

    the t.racks DSP 306

    Varastossa
    329 €
  10. Tascam TA-1VP

    Tascam TA-1VP

    Varastossa
    345 €
    445 €
  11. the t.racks DSP 206

    the t.racks DSP 206

    Varastossa
    298 €
  12. the t.racks Limit 2/2

    the t.racks Limit 2/2

    Varastossa
    129 €
  13. Warm Audio WA-2A

    Warm Audio WA-2A

    Varastossa
    888 €
    999 €
  14. UnderToneAudio UnFairchild 670M II

    Under­To­neAudio UnFairc­hild 670M II

    Varastossa
    10 090 €
  15. tc electronic TC2290-DT

    tc elect­ronic TC2290-DT

    Varastossa
    218 €