Buzz Audio ESSENCE Optical Compressor for 500 Series
Description
The essence control circuit design is based on the Buzz Audio SOC-1.1 Stereo Optical Compressor but the main audio path utilises our BE40 and BE50 True Class A amplifiers along with high spec Lundahl input and output transformers. The input transformer is directly coupled to the Buzz proprietary Opto gain reduction element (completely passive input), amplified and then balanced via the output transformer - a very simple but gutsy signal path!
The essence control circuitry utilizes the Differential Drive Side Chain (DDSC) topology that was developed for the SOC-1.1. This system, which processes positive and negative audio waveform in seperate paths, provides the incredibly musical characteristic you will hear with this unit. The DDSC design also provides for a much faster attack time compared to most other LDR based optical compressors.
Simple side chain equalizers have been provided to allow the user to adjust the sensitivity of the compressor at high and low frequencies. In addition, a side chain insert point is provided for more complex EQ and compressor "keying".
The essence consumes 2 slots within a 500 Series rack. The input/output (I/O) connectors associated with the first slot carry the main audio path. The I/O connectors associated with the second slot are used for a side chain insert point (send and return). The insert can be switched in/out of circuit and monitored via front panel switches.
PLEASE NOTE - RACK COMPATIBILTY
Each Buzz Audio Essence module uses 2u rack spaces and draws 120mA +/- 15-18 volts DC, as supplied by rack power supply. Most currently manufactured rack systems will easily power a full compliment of essence units, but some older rack systems may have insuffcient power, if in doubt, please check with your rack manufacturer. We recommend the API Lunchbox and VPR500 racks.
Features:
• API 500VPR Series rack module format - plug in and play
• Advanced analogue technology - not a clone or copy of products from the past
• Powerful fully discrete hi-bias, wide bandwidth, differential Class A amplifiers
• Passive transformer coupled input, transformer coupled output
• Side chain insert point
• Side chain monitor selector
• On board side chain EQ
• Unique Differential Drive Side Chain design
• May be linked to multiple essence units within one rack
• Switchable 10 segment VU meter
Controls and Functions:
• GAIN - sets the output gain from 0dB to +15dB.
• DRIVE - sets the amount of compression applied to the signal, clockwise rotation means more compression.
• ATTACK - 4 position switch with attack time settings of 1mS, 15mS, 70mS and our excellent Auto mode.
• RELEASE - 6 position switch with recovery time settings of 100mS, 200mS, 400mS, 800mS, 1600mS and the intelligent Auto mode.
• RATIO - 4 position switch sets the depth of compression from light to heavy, 2:1, 5:1, 10:1, 20:1 all with the soft knee action.
• METER - switched to read gain reduction or input and output level, a PCB jumper sets the zero level reference from +4dBu or +14dBu.
• BYPASS - toggle switch used to hard wire bypass the essence.
• S.C. MON - allows you to hear the side chain signal (the side chain eq) and the side chain insert return signal.
• S.C. HI EQ - applies 8dB at 10kHz of boost or cut to the side chain signal and therefore to the compression.
• S.C. LO EQ - applies 8dB at 100Hz of boost or cut to the side chain signal and therefore to the compression.
• LINK - using the 500 frame link system, two Essences can be linked for stereo operation.
• S.C. INS - this switch engages the side chain insert point which are the input/output connectors associated with the second slot the Essence uses.