Type 120-A
First H.H. Scott (dedicated) Equalizer-Preamp
uses a 12AX7
for phono preamp-duty
and a pair of 12AU7's for tone and
AF amp duties
(click on drawing for detailed view)
H.H. Scott preamp designs typically consist of a low-level (magnetic
phono) and the no-longer used direct
tape head (NAB) inputs preamp. Various equalization curves were in use before the 1955
adoption of the RIAA phono-EQ standard, hence the "Record Compensator or
EQ circuitry.
In addition, Scott preamps typically
feature line-level (auxiliary, TV, Tuner, Extra, etc.) inputs suitable for modern CD, and Tape
aux inputs.
Typically, following the phono preamp section are the tone
(treble/bass) controls and filters (rumble/scratch), Loudness/Volume control
sections.
Integrated amps
often eliminated the final cascade follower and deliver the audio signal directly from the tone/AF
amp to the phase splitter. Tuners also incorporate a line-level AF preamp
stage.
