Prometheus is a TVC passive (Transformer Volume Control).
http://www.audiocircle.com/image.php?id=7513
These tend to have a "signature" sound, and are not as transparent to the source as a potentiometer, ldr, or switched resistor based passives. Some love their colouration, some don’t. And if they use a winding on the transformer/s with some gain they can "ring" a bit. (they also tend to be expensive for a passive)
Cheers George
http://www.audiocircle.com/image.php?id=7513
These tend to have a "signature" sound, and are not as transparent to the source as a potentiometer, ldr, or switched resistor based passives. Some love their colouration, some don’t. And if they use a winding on the transformer/s with some gain they can "ring" a bit. (they also tend to be expensive for a passive)
Cheers George