Buzz Audio SOC-20 Discrete Mid Side Optical Compressor

Available in Black & Silver.

The SOC-20 is a design extension of our original SOC-1.1 optical compressor featuring the same Differential Drive Side Chain design but a discrete Class A signal path, complete with Lundhal output transformers. Inspired by ideas from our users, we have incorporated a mid-side (or sum and difference) encoder and decoder. How this works is when set to M/S mode, the stereo input is divided into signals that are common to left and right (mid) and signals that are not (side). The divided signals are sent to each channel of the SOC-20 then recombined at the output. So you can now adjust the dynamics of the stereo image (be it a stereo sample, synth sound or full mix) like never before. Check out the audio samples to see how powerful this process can be.

But it does not end there, at the flick of a switch, a high pass filter reduces the compressor sensitivity to low frequencies for more bass punch when used on program material. We have also included a fully balanced side chain insert point so you can add additional equalisation to the compressor characteristic or “key” the compressor with another source. There are 5 attack settings and 6 release settings including our magnificent auto release mode and the 5 ratio settings offer very gentle to full on gain reduction possibilities.

Controls

Drive – variable pot that sets the amount of compression.
Output dB – variable pot that adds gain at the output to correct for lost level.
Attack – rotary switch with 1mS, 10mS, 25mS, 50mS selections and the excellent AUTO mode.
Ratio – rotary switch with 2:1, 4:1, 6:1, 10:1 and 20:1 selections – all soft knee.
Release – rotary switch with 100mS, 200mS, 400mS, 800mS 1600mS selections and our suberb AUTO mode.
Bypass – hard wire unit bypass to compare compressed and uncompressed signals.
Meter – switches the VU meter between input/output levels or amount of compression.
S/C HPF – inserts a 170Hz high pass filter into the side chain for added bass punch.
S/C Insert – engage the external side chain insert point and monitor the side chain signal.

There is also a handy power On/Off switch, a channel A/B Link switch which is useful when the SOC-20 is used on stereo mixes with hard panned sounds, and the global Stereo or MS mode switch. The large knobs with pointers allow for accurate resetting of the compressor if needed.

Specifications

Maximum Input Level Line +32dBu
Maximum Output Level Line +27dBu
Maximum Input/Output Level S/C Insert +22dBu

Noise -95dBu Stereo Mode, -90dBu M/S Mode (measured with no make up gain and A Weighted).

Gain variable from 0dB to +15dB

Frequency Response
3Hz to 120kHz measured with +10dB gain and no gain reduction.

Harmonic Distortion
No gain reduction 0.08% @ 100Hz, 0.025% @ 1kHz, 0.02% @ 10kHz, 0.05% @ 100kHz
With 20dB gain reduction (Attack AUTO, Release 16) 0.1% @ 100Hz, 0.06% @ 1kHz, 0.04% @ 10kHz
With 20dB gain reduction (Attack AUTO, Release AUTO 2% @ 100Hz

Standard Operating Level +4dBu = 0 VU meter display.

Size 2 Unit 19″ rack mount, (482Wx88Hx250D).

Power requirements 230V/115V selectable, IEC detachable power cable.

Specifications are typical of a production unit and are subject to change without notice.
0dBu reference = 0.775 volts RMS.