Audio Database
PAS-3X
Commentary

A tube type preamp built by Dynaco based on a consistent basic policy.

Distortion is reduced by applying negative feedback across the entire circuit.

A special volume is used for the tone control, and when the knob is placed in the middle point, the tone control circuit is detached and becomes a flat amplifier.
Also, both Bass and Treble adjust the left and right channels independently.

With a special input circuit, it is possible to use a microphone or phono.

There was a wooden case sold separately.

Model Rating
Type Tube type stereo preamplifier
Frequency characteristic 10 Hz ~ 40 kHz ± 0.5 dB (Aux)
Harmonic distortion factor Below the measurement limit
Cross modulation distortion factor 0.05% or Less (at 2 V, Rated Output)
Signal-to-noise ratio Phono:74dB
Aux:85dB
Input circuit Phono, Tape head, Special (used as Phono2)
Mic (can be used as Phono3), Tape head
AM-FM, FM-multi, Tape, Spear
Input sensitivity Phono:2.5mV
Tape head:188mV
Spear:100mV
Input impedance Low level : 50k Ω
High level : 250k Ω
Output voltage 10V/100k Ω
Phono allowable input voltage 250mV
Tone control Bass : ± 20 dB (20 Hz)
Treble : ± 18 db (20 khz) * ± 14 db in the 1973 catalog
Left-right independent
Semiconductor used 12AX7 : 4 Pieces
12X4 : 1 Piece
External dimensions Width 343x Height 108x Depth 230 mm
Weight 4.8 kg (according to 1973 catalog)
5 kg (according to 1974 catalog)
4 kg (according to 1976 catalog)
Sold Separately PAT-4/PAS-3X Common Wooden Case (¥ 3,900, circa 1970)
Wooden Case DW-1 (¥ 6,500, around 1976)