Technics SU-3300

Commentary

A pre-main amplifier using an audio squelch circuit developed by Technics engineers.

The first stage of the equalizer is composed of a differential amplifier circuit, and the second stage is composed of a Darlington connection circuit to increase the gain of the first stage.
A specially selected low-noise PNP transistor is used for the first stage, and a low-noise NPN transistor is used for the second stage to improve SN and circuit stability.

The power amplifier section is composed of an all-stage direct-coupled OCL circuit with excellent low-frequency characteristics and damping factor, and the last stage is composed of a complete complimentary service combining PNP and NPN transistors to improve the characteristics.
The first stage employs a differential amplifier circuit with excellent DC stability, and achieves stable operation even when temperature and power supply voltage fluctuate.

Audio squelch circuit is used.
This circuit eliminates noise when there is no signal on a record or tape (noise before the performance starts, between songs, or after the performance ends) and realizes comfortable program performance. It is designed so that the circuit turns off automatically as soon as the performance starts.
The level can be adjusted according to the noise level.
When the selector is set to the SQUELCH & HI-FILT position, it also functions as a high filter that attenuates high frequencies above 6 kHz at 6dB/oct.

Two pairs of tape monitor circuits are built in, allowing for dubbing.

Equipped with a low filter, loudness and tone control.

It is equipped with an amplifier for the microphone, and the level of the microphone and program source can be adjusted with the volume knob.

The volume is a preset type. If you preset the outer knob, the rotation of the volume knob stops at that position.

Built-in speaker protection circuit.

Equipped with pre-main separation terminal.

Model Rating

Type	Solid state pre-main amplifier
Circuit system	Power Amplifier Section : Fully complimentary service all-stage direct-coupled differential-amplification OCL circuit Preamplifier Section : Differential amplified Darlington connected equalizer circuit NFB type tone control Audio Squelch circuit
Power Amplifier Unit
Music Power (IHF)	56W (4 Ω) 46W (8 Ω)
Effective power (IHF)	21W/21W (4 Ω) 17W/17W (8 Ω)
Power band wiz	6 Hz to 30 kHz, -3dB (Distortion 0.2%)
Frequency characteristic	6 hz to 130 khz, + 0 -3dB
Distortion factor (at effective output)	Not more than 0.2%
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1)	0.2% or Less (Effective Output)
Signal-to-noise ratio (IHF)	110 dB or more
Damping factor	50 (at 8 Ω Load)
Input Sensitivity / Impedance	600mV/50k Ω
Load impedance	4 Ω ~ 16 Ω
Preamplifier Section
Input Sensitivity / Impedance	Phono Low : 3mV/50k Ω Phono High : 5mV/50k Ω Tuner : 200mV/60k Ω AUX1, 2 : 200mV/60k Ω MIC : 3mV/50k Ω
Tape Monitor 1, 2	Rec Out (output) : 200 mV Playback (input) : 200mV/60k Ω Rec/Play (DIN) : (Input) 200mV/60k Ω, (Output) 30mV/80k Ω
Output Voltage / Impedance	Rated output : 600mV/500 Ω Maximum Output : 1.5V/500 Ω
Phono allowed input	Low:130mV High:260mV
Total harmonic distortion factor	Not more than 0.2%
Signal-to-noise ratio (IHF)	Phono:76dB Tuner:86dB AUX1, 2 : 86 dB
Frequency characteristic	Phono : within ± 1 dB of deviation from RIAA standard curve Tuner, AUX1, 2 : 8 Hz to 80 kHz, + 0 -3dB MIC : 30 Hz to 6 kHz, + 0 -3dB
Tone control	Bass : 100 Hz, + 9 dB to -9dB Treble : 10 kHz, + 9 dB to -9dB
Loudness control	100 Hz, + 9 dB (Volume -30dB)
<General>
Semiconductor used	Transistor : 40 Diode : 12
Pwer	100 VAC, 50/60Hz
AC outlet	Switched : 1 system Unswitched : 1 line
Power consumption	55W
External dimensions	Width 410x Height 140x Depth 300 mm
Weight	8kg