Lumi utilizes the old age electroluminescence principle. The most famous example of this compressor type is Urei LA2A. Lumi is a superbly crafted stereo unit with excellent channel balance and tracking. The amplifier section is a single-ended transformer coupled stage capable of huge headroom and nice sonic flavour. An extra load can be switched on to produce about 4% of second harmonic distortion at +22 dBU to give more character to sterile tracks.
A limit/comp switch does exactly what it says. In the limit-position compression ratio turns softly to full limiting. In the compression mode the final ratio is 4:1 after a really wide soft knee area. It is pretty amazing how much can be done with these options only.
There is also a side chain high pass filter. The corner frequency is at about 300 Hz and the slope is first order. The characteristically fast attack time of an EL-compressor makes it sometimes necessary to control the degree to which bass frequencies affect compression.
If you are familiar with LA2A, you know what I'm trying to tell, if not, just believe it:
This superficially simple compressor does miracles especially to vocals, guitars, bass etc. It is NOT as versatile as Vari-Mu, but the symbiosis of an EL-panel and a light dependent resistor as a gain reduction element "makes music" like no other compressor topology ever.Technical specs
|Maximum compression||26 dB|
|Channel balance and tracking, 0-10 dB compression||<0,5 dB|
|Frequency response 0/-0,5 dB||8Hz - 22kHz|
|Distortion @ 22dBU 100 Hz -> "clean" and "warm"||0,5% and 4%|