Buzz Audio SOC-1.1 Classic Stereo Optical Compressor
The use of Light Dependant Resistors (LDR) as the control element of an audio compressor was pioneered in the 1960’s and we are all aware of the value placed on those famous vintage “LA” units. The SOC-1.1 was designed not to copy, but to take that signature and improve on it by offering the user more control. With 4 ratio settings, 3 attack options and 6 release times, the SOC-1.1 puts you in command of the dynamics rather than dealing with set parameters.
The design of the SOC-1.1 back in 1993 lead to the development of our Differential Drive Side Chain circuit which is unique to Buzz Audio and is used in all our optical compressors. This circuit processes the negative and positive portions of the audio wavefrom separately (attack and release parameters) and along with the “soft knee” characteristic creates a very smooth coherent compression action. The SOC-1.1 is perfect for recording vocals, acoustic instruments and is really cool on bass guitar. On the mix buss the SOC will provide instant glue and will never dig holes in your tracks.
One of the short comings of the LDR is it can be sluggish to respond to changes in light and therefore the response time of an optical compressor can be quite slow. However, our side chain design incorporates a clever little circuit to speed up the attack time to less than 1mS in fast mode and the use of small LDR elements results in a much faster release when required. All this makes the SOC-1.1 a lot more versatile (and cheaper!) than vintage compressors with fixed attack and slow release timings.
Drive – turning it clock wise increases compression, which is way more sensible than counter clock wise! Output dB – variable pot that adds up to 15dB gain at the output to correct for lost level. Attack – toggle switch with FAST (1mS) or SLOW (50mS) selection and our excellent AUTO mode. Ratio – rotary switch with 4 settings for depth of compression, 2:1, 5:1, 10:1, 20:1. Release – rotary switch selects recovery time of 100mS, 200mS, 400mS, 800mS, 1600mS and a superb AUTO mode. Meter – monitor input or output level or amount of compression on the VU meter. Bypass – hard wire unit bypass to compare compressed and uncompressed signals. There is also a handy power On/Off switch and a channel A/B Link switch which soft links the sidechain circuit which is useful when the SOC-1.1 is used on stereo mixes.
Max Input/Output Level +23.5dBu (measured with 2k ohm load and 0dB output gain makeup) Frequency Response 4Hz to 250kHz (-3dB points with no gain reduction)| Slew Rate 20V/uS Harmonic Distortion less than 0.008% (measured 100Hz to 10kHz with no gain reduction) Harmonic Distortion less than 0.03% (measured 100Hz to 10kHz with 20dB gain reduction, Atk-AUTO, Rel-16) Residual Output Noise typically -90dBu, -100dBu A wtg (0dB output gain makeup, 150R source impedance) Channel to Channel Crosstalk below noise Standard Operating Level +4dBu = 0 VU meter display Size 2 Unit 19″ rack mount, (482Wx88Hx250D) Power requirements 230V/115V selectable on rear, IEC detachable power cable
Specifications are typical of a production unit and are subject to change without notice. 0dBu reference = 0.775 volts RMS.