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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

HHS_120A_SD_web.jpg (218434 bytes)
(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.


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