These exceptional tube phono enhancers allow on-the-fly selection of the entire range of phono equalization curves used by prominent record labels throughout history. In addition, we have implemented subtle tone control facilities to compensate for sound degrading artifacts which may have been introduced during the recording or cutting process of a given record. The Enhancer’s unique tone control circuitry shapes the playback deemphasis curve itself, within wide limits, without the use of any clumsy conventional tone control circuitry. Bass, mid-bass and treble are independently variable by means of rotary knobs.