DYNACO PAT-4

Commentary

This stereo preamplifier was developed as the second series of Dynaco's solid state amplifier following the Stereo 120 power amplifier.
Tube type preamplifier While inheriting the advantages of the PAS-3X, it is designed with more functions.

As few as four transistors per channel are needed to satisfy the required function, and the coloring of reproduced sound is suppressed by the refinement of the circuit.
In addition, it can be used at 600 Ω load, so it is designed to withstand professional use.

The tone control circuit is designed to have a completely flat characteristic at the midpoint.
In addition, it is a double channel type that can operate the left and right channels separately.

Equipped with a high-cut filter that can be switched in 3 stages.

For stereo / mono switching, Ach, Bch, and Blend can be operated by two rocker switches.

The front panel has a spare input terminal for connecting a tape deck, microphone, etc.

There was a wooden case common to PAT-4 and PAS-3X sold separately.

Model Rating

Type	Solid-state stereo preamplifier
Frequency characteristic	Aux : 10 Hz to 100 kHz ± 0.5 dB Phono : 20 Hz to 20 kHz ± 1 dB
Total harmonic distortion factor	0.05% or Less (2 V Output, 20 Hz ~ 20 kHz)
Cross modulation distortion factor	Not more than 0.05%
Signal-to-noise ratio	Phono : 70 dB (10 mV input) Aux : 85 dB (0.5 V input)
Tone control	Bass : ± 16 dB (50 Hz) Treble : ± 12 dB (10 kHz)
Output level	10 V (Hi impedance) 5 v (600 Ω)
Input impedance	Phono : 47k Ω Tape head, High level : 100k Ω Audio output : 600 Ω Tape : 600 Ω
Input terminal	Mag (Hi, Low, one system each), Ceramic, Tape head, Tape amp Tuner, Spare (2 sets), Special (Mic, Phono 2)
Output terminal	For Audio (2 sets, 1 set with switch) Front panel output For tape recording
Semiconductor used	Transistor : 8 Diode : 2 pcs
Power consumption	5W
External dimensions	Width 345x Height 105x Depth 205 mm
Weight	4.5kg
Sold Separately	PAT-4/PAS-3X Common Wooden Case (¥ 3,900, circa 1970)