Buzz Audio SOC-20 Class A Stereo Optical Compressor

Buzz Audio SOC-20 Stereo Optical Compressor

Dual-channel precision optical compressor optimized for the stereo buss with features not found on any other LDR compressor manufactured today

Available in Black or Silver

The entire audio path of the Buzz Audio SOC-20 optical compressor is made using proprietary Class A discrete transistor BE41 amplifiers with a Lundahl LL1517 transformer at the output. A special low impedance power supply design is used to enhance the sound quality of the amplifiers by providing very stiff power rails. This overall combination produces a unique sound character with full bass and a vibrant top end void of any midrange harshness. Whilst the SOC-20 is not a clone of any vintage units, it's design is inspired by the use of the LA2 and LA3 by it's designer Tim Farrant.

Mid-Side Processing Power

Not only can the SOC-20 be used in dual mono or stereo mode, Buzz Audio have also incorporated a Mid-Side (or sum and difference) encoder and decoder. When set to MS mode, the stereo input is divided into signals that are common to left and right (called the mid) and signals that are not (called the side). The divided signals are sent to each channel of the SOC-20 then recombined at the output thereby allowing you to adjust the dynamics and width of the stereo image. This process has application on a wide range of stereo sounds including the mix buss and electronic music sub mixes. Check out the audio samples to see how powerful this process can be.

Side Chain Flexibility

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. Buzz have also included a fully balanced side chain insert point so you can add additional equalization to the compressor characteristic or "key" the compressor with another source to create those pumping effects found in modern music styles. The side chain monitor function allows you to hear what is returning into the insert point and also monitors the mid or side signal when the compressor is used in MS mode.

Control Genius

The unique differential side chain circuit of the Buzz Audio SOC-20 splits the audio into positive and negative waveform and processes it separately to obtain a differential drive into the custom BE45 electro-optical attenuator. There are 5 compressor attack settings and 6 release settings that cover a wide range of response possibilities. In addition, intelligent auto modes allow for true "set and forget" operation. The 5 "soft knee" ratio settings allow for gentle to strong leveling, with the selected ratio only actually achieved at 10 dB of gain reduction. The SOC-20 opto compressor is extremely musical - ideal for vocal and instrument recording plus it is equally at home on the stereo buss to glue your mixes together - a truly multi-purpose studio compressor now available in a mastering version.

Control and Functions

• 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 characteristic
• RELEASE: rotary switch with 100mS, 200mS, 400mS, 800mS 1600mS selections and superb 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 170 Hz 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
• LINK A/B: joins the side chain of each channel for stereo operation with "soft" tracking
• There is also a locking toggle to select STEREO or MID-SIDE mode and a handy POWER on/off switch

Features:

• The vivid sound of discrete Class A amplifiers in the signal path
• The lush tone of Lundahl audio output transformers
• Culmination of 20 years design experience
• Robust chassis construction
• Onboard linear power supplies - no wall warts
• Easy to use control layouts

 STL Pro Audio is an authorised Buzz Audio Dealer.