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This is a pre-main amplifier that pursues higher sound quality by adopting two independent power transformers on the left and right sides to enhance dynamic characteristics. The EQ section employs first stage differential, 3-stage direct connection, final stage class A operation, pure complimentary service SEPP, and two positive and negative power supplies to reduce distortion and improve characteristics by using carefully selected NFB elements (nichrome evaporated metal film resistance with ± 1% tolerance and ± 50ppm/c temperature characteristic, styrene condenser with ± 2% tolerance). In addition, a low-noise transistor is carefully selected for the first stage differential amplifier to improve the SN ratio. By supplying a voltage of ± 25 v to the circuit, a maximum allowable input of 250 mv is obtained. In order to maximize the performance of various cartridges, it is equipped with a change-over switch which can select 4 types of cartridge load capacity, so that load capacity suitable for the cartridge to be used can be set. The 2-stage direct-coupled flat amplifier in the control section reduces distortion by selecting the operating point in the linear region of the transistor with the first stage as a differential amplifier, and the tone control employs 3-stage turnover switching. The control knob is equipped with an easy-to-use Klix/Klukš top and is also equipped with a tone on-off switch. A 32-step attenuator is used for the volume, and the gang error between the left and right channels is as small as 0.5 dB or less, and the error with the indicated value on the panel surface is within ± 0.5 dB. In addition, it is equipped with a muting lever of -20dB for more delicate volume adjustment. The power amplifier circuit consists of ± 2 power supply, 2-stage differential amplifier current mirror circuit, final stage parallel push-pull circuit and pure complimentary service OCL circuit. The dual transistor with stable characteristics is used for the differential amplifier in the first stage, and a current mirror circuit is used for the pre-driver stage. Sufficient NFB is applied to reduce distortion, and the part after the pre-driver is used as a push-pull drive to reduce. A chimney style radiator with good heat radiation effect is used for heat radiation. The power supply section employs two power transformers and a 10,000 μ Fx4 capacitor to eliminate channel interference and improve channel separation. The protection circuit consists of a power relay and a quick response electronic circuit. It also eliminates power-on clicks. It is equipped with functions such as separation terminals of preamp and power amplifier, 2-system tape monitor, loudness contour, low-cut (subsonic) and high-cut filter. Type Stereo pre-main amplifier Power Amplifier Unit Circuit system 2-stage all-stage direct-coupled parallel PP pure complimentary service OCL Effective power (Both channel drive, 20 Hz to 20 kHz) 75W 75W (4 Ω) 60W 60W (8 Ω) Harmonic distortion factor (20 Hz to 20 kHz) % (at effective output) % (8 Ω at 30W output) % (8 Ω at 1W output) Intermodulation distortion factor (50 hz : 7 khz = 4 : 1) % (at effective output) % (8 Ω at 30W output) % (8 Ω at 1W output) Output Bandwidth (IHF, both channel drives) 5 Hz to 45 kHz (Distortion Factor %) Frequency characteristic 5 Hz to 100 kHz 0 -1dB Input Sensitivity / Impedance Power amp in : 1V/50k Ω Output terminal Speaker A / B : 4 Ω ~ 16 Ω Speaker A B : 8 Ω ~ 16 Ω Headphone : 4 Ω ~ 16 Ω Damping factor 30 (20 Hz ~ 20 kHz, 8 Ω) S/N 110 dB (IHF, A-network, short circuit) Preamplifier Section Circuit system Equalizer amplifier : First stage differential 3-stage direct connection Class A SEPP Tone control section : first stage differential 2-stage direct connection flat amplifier Turnover 3-stage switching NFB-type tone Input Sensitivity / Impedance Phono1, 2 : Ω Cartridge Load Capacity : 100 pf, 200 pf, 300 pf, 400 pf (for both Phono1 and 2) Tuner, Aux, Tape play1, 2 : 150mV/50k Ω Phono maximum allowable input Phono1, 2 : 250 mV (1 kHz, harmonic distortion rate %) Output Level / Impedance Tape rec1, 2 : 150 mV Pre out : 1V/2k Ω, 6V/2k Ω (max) Harmonic distortion factor (20 Hz to 20 kHz) % (1 V Output) 0.1% (6 v Output) Frequency characteristic Phono : 20 Hz to 20 kHz ± 0.2 dB Tuner, Aux, and Tape play : 5 hz to 50 khz 0 to 1 db Tone control Bass: ± 10 dB (25 Hz, 50 Hz, 100 Hz) Turnover frequency : 100 Hz, 200 Hz, 400 Hz Treble: ± 10 db (8 kHz, 16 kHz, 32 kHz) Turnover Frequency : 2 khz, 4 khz, 8 khz Filter Low : 15 Hz, 6dB/oct. High : 8 kHz, 6dB/oct. Loudness contour (Volume -40dB) 6dB(100Hz) 3dB(10kHz) Muting -20dB S/N (IHF, A-network Short circuit) Phono:75dB Tuner, Aux, Tape play : 95 dB AC outlet Power switch interlock : 2 systems Power supply voltage 100 VAC, 50Hz/60Hz Power consumption 150W (Electrical Appliance and Material Control Law) External dimensions Width 420x Height 150x Depth 376 mm Weight
