Spectra 1964 Model C610 Complimiter is a rackmount dynamics processor built on the unchanged 601 compressor and limiter circuit from the original Model 610. The current version adds XLR and Phoenix connectors, quality transformers, a selectable input pad, buffered VU metering and overload indication.
Two processors working at the same time
The C610 does not make you choose between limiter and compressor. Ultra-fast peak limiting guards transients while slower programme compression shapes the tail underneath it. A snare keeps its attack and its decay rises smoothly, without the pumping that appears when a single VCA stage is asked to do both jobs.
Compression that leaves the tone alone
Response stays within 0.1 dB from 20 Hz to 40 kHz and distortion remains under 0.01% even with 30 dB of gain reduction. That is unusual: most compressors visibly change character at that depth. Ratio is continuously variable from 1.1:1 to 100:1 and release runs from 50 milliseconds to over 10 seconds, so the same unit handles gentle vocal levelling and hard drum bus limiting.
KEY FEATURES
- Original 601 compressor and limiter circuit from the Model 610
- Simultaneous peak limiting and programme compression
- Continuously variable ratio from 1.1:1 to 100:1
- Automatically variable attack time driven by programme material
- XLR and Phoenix connectors with quality transformers
- Buffered VU metering and overload indication
TECHNICAL SPECIFICATIONS
- Input impedance: 600 Ohm
- Output impedance: 2.5 kOhm
- Input pad: three positions (no pad, +4 dBu, +22 dBu nominal)
- Maximum gain: 56 dB
- Threshold attack level: -40 dBm
- Maximum output: +18 dBu
- THD: less than 0.01% at 30 Hz - 20 kHz, +16 dBm, with up to 30 dB of compression
- Signal to noise: better than 80 dB below +4 dBm output with -40 dBm input, 20 Hz - 20 kHz
- Frequency response: +/- 0.1 dB, 20 Hz - 40 kHz
- Compression and limiting ratio: 1.1:1 to 100:1, continuously variable
- Attack time: 100 nanoseconds to 1.2 milliseconds, automatically variable
- Release time: 50 milliseconds to over 10 seconds, continuously variable



