Pioneer SA-6600II
¥ 29,800 (released in 1976)
Commentary
This is a pre-main amplifier that emphasizes sound quality and has an improved circuit to draw out the necessary power while minimizing distortion.
The NFB circuit of the equalizer section uses carefully selected elements such as a resistor with an error of less than 1% and a capacitor with an error of less than 2%. In addition, a dynamic margin of a maximum allowable input of 200 mV is obtained by using a high voltage IC and ± 2 power supply (+ 21V/-19V).
The flat amplifier uses a two PNP-NPN configuration with low noise and low distortion factor, and uses a circuit that increases the power supply utilization factor and expands the dynamic range.
The next stage tone control circuit uses a CR type, an 11-point an 11-point click-stop type is used for the knob, and a tone on-off switch is installed to make the tone flat only by operating the lever switch.
The first stage PNP differential and all stages direct connect pure complimentary service OCL system are adopted for the circuit configuration of the power amplifier section.
The pre-driver stage is a constant-current load that reduces the low-frequency time constant, enabling extended playback to the ultra-low frequency range. In addition, the pre-driver stage reduces the load on the pre-driver, allows a large gain in the linear region of the transistor, and achieves excellent characteristics by stably applying NFB to the ultra-low frequency range.
The power supply uses a large transformer and a 6,800 μ Fx2 capacitor.
The protection circuit is composed of an electronic circuit using TRIAC and a fuse.
In addition, in order to reduce the clicking sound when the power is turned on and off, a power muting circuit with three transistors is installed.
Equipped with a loudness contour and a 2-system tape monitor.
Model Rating
Type | Stereo pre-main amplifier |
Circuit system | Power Amplifier : Pure complimentary service OCL Equalizer : High voltage IC with two positive and negative power supplies Tone control part : Positive / negative 2 power supply 2-stage direct connection flat amplifier, CR type tone |
Effective power (Both channel drive, 20 Hz to 20 kHz) |
27W + 27W (4 Ω) 25W + 25W (8 Ω) |
Harmonic distortion factor (20 Hz to 20 kHz) | 0.1% (Effective Output) 0.05% (8 Ω at 13W output) 0.05% (8 Ω at 1W output) |
Intermodulation distortion factor (50 hz : 7 khz = 4 : 1) | 0.1% (Effective Output) 0.05% (8 Ω at 13W output) 0.05% (8 Ω at 1W output) |
Output Bandwidth (IHF, both channel drives) | 5 Hz ~ 40 kHz (Distortion Factor 0.1%) |
Damping factor | 30 (20 Hz ~ 20 kHz, 8 Ω) |
Input Sensitivity / Impedance | Phono : 2.5mV/50k Ω Tuner, Aux, Tape play1, 2 : 150mV/50k Ω |
Phono maximum allowable input | 200 mv (1 khz, 0.1% harmonic distortion rate) |
Output Level / Impedance | Tape rec1, 2 : 150 mV Speaker AORb : 4 Ω ~ 16 Ω Speaker A + B : 8 Ω ~ 16 Ω Headphone : 4 Ω ~ 16 Ω |
Frequency characteristic | Phono : 20 Hz to 20 kHz ± 0.3 dB Tuner, Aux, Tape play : 10 hz to 40 khz + 0 -1dB |
Tone control | Bass:+9dB -8dB(100Hz) Treble:+8dB -6dB(10kHz) |
Loudness contour (Volume -40dB) |
+8dB(100Hz) +5dB(10kHz) |
S/N (IHF, A-network Short circuit) |
Phono:73dB Tuner, Aux, Tape play : 93 dB |
<General> | |
Semiconductor used | Transistor : 25 IC : 2 Diode, etc. : 16 pcs |
AC outlet | Power switch interlock : 2 systems Power switch not linked : 2 systems |
Power supply voltage | 100 VAC, 50Hz/60Hz |
Power consumption | 85W (Electrical Appliance and Material Control Law) 200W maximum |
External dimensions | Width 380x Height 139x Depth 306 mm |
Weight | 7.2kg |