Denon PMA-701

Impressive switchknob silver stack from Denon's glory days, with a twist : PCC.

Ahh - PCC means Phono Crosstalk Canceller, something which was fairly shortlived (by Denon) but which resurfaced here and there throughout the 1980s and mostly by Marantz in the early 1990s with the SX-72 "scratch remover" unit and Philips with the IS5022 studio toolbox.

Denon's PCC wasn't using a Philips TDA as it was, naturally, all analogue.
So here are two wide-bandwidth phase shifting circuits that track cracks and pops on each stereo channel, reverse phase when necessary then matrix the two different signals (per stereo channel) to cancel the pops out of the music signal. In theory :)

This works by adjusting pops sensitivity separately for L to R signal and R to L signal - countless hours of tweaking ahead !
Denon even went as far as making a dedicated PCC-1000 unit (an extra-rare rarity) but PCC vanished rather quickly : by late 1978, it was unheard of in the Denon lineups...

The PMA-701 and smaller PMA-501 differ in this : the 701 has three transformers (two on the 501), more power, four big 10,000µF caps (four 6,800µF on the 501), a low-cut filter (none on the 501), and black anodized heatsinks. The rest is identical : full DC differential amplifiers, three-stage tone controls, three-step muting and three loudspeaker pairs' outputs.

The PMA-701 and its TU-701 tuner sold somewhat well in Europe but are much less remembered than Denon's next mid-end lineup : PMA-850 (and variants) and TU-850.