Operation is extremely simple. Is sent, rule-level input and output is the result and bannnng LISTENING!
Used on a voice session (R & B), but I have heard mix with low or even Guitard (rock, blues, bluegrass). The sound is amazing and is incredibly well sit all that goes dedant! Now you have to like this type of sound.
Extremely rare and is found almost exclusively in Australia. Family of RCA and other BA6B Fairchild (although the legend is still "above". Major appliances, heating small room but a unique sound! Made a lil google it and read the articles of your favorite ... If your engineers grandfather has one, know it, you have a lil treasure (and incidentally if you want me to sell it ...