first ES tuner : a favorite in Japan
back then, just below Kenwood's L-02T :-)
the 555 had one thing really different and that was ACT
: Audio Current Transfer. Instead of transmitting the audio signal
to the amp in the form of voltage, it used current.
you hear the difference? Most definitely !... said the litterature.
Also, it used the famed Direct Comparator circuit (CX778),
directly responsible for a stunning s/n ratio and which is used
on Sony's tuners until... the late '90s.
ACT needed a mini-DIN plug on the tuner side and a regular pair
of plugs on the amp/preamp side with a sort of box in between the
two - a rare accessory these days... Optional Japan-only TAC-75 sideburns were available - a rare accessory.
top FM tuners are quite often not very much talked about but they
deserve non-slanted sonic comparisons - they generally slash a lot
of what is out there - ST-A7B,
the price of an average tuner a few years ago, you can now own one
of the all-time greats - the Sony ST-S555ES" (said the