Optonica - SM-4646 HB Solid state integrated amplifier - Multiple models
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Optonica SM-4646 HB stereo amplifier, manufactured in 1979, in excellent condition and fully functional, weighs 16 kg, with dimensions 44 cm W × 37 cm D × 14 cm H, serial number 80801849, includes power cable.
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Description from the seller
I propose a fantastic Optonica SM-4646 amplifier, an elegant, all-black model, a historic piece from the Sharp/Optonica high-end series. The black series was considered the “design” version for this amplifier.
Superb, dynamic, and powerful sound, ideal for those seeking vintage audio quality without compromise. The unit is perfectly functional and in excellent condition. The volume knob was restored a few days ago, removing scratches from the surface.
Awarded in 1977 with the prestigious French Laurier d’Or (Golden Laurel) for “exceptional functionality, design, and performance,” a recognition reserved for the best audio products of the era.
The amplifier features three power transformers for “Delta Power,” DC current stages in Class A (preamplifier + pre-driver), two large main capacitors of 13,600 µF, low-noise FETs and differential amplifiers, a 4-way volume attenuator, and a total weight of 16 kg.
The center transformer powers the preamplification and driving stages in Class A, while the other two, independently, power the left and right output stages in Class B.
From the outside it doesn’t look like that, right?
Indeed – but either it wasn’t enough to climb to the top tier of the market, or it was too much to keep prices affordable and secure a solid position in the mid-range.
Esthetically it looks a bit heavy and clearly leans toward the 60s rather than the budding 80s. Which is quite fascinating.
Main Technical Specifications
Output Power (RMS): 2x 70 W into 8 Ohms (1 kHz, 0.05% THD) and 2x 95 W into 4 Ohms (1 kHz, 0.05% THD); 2x 60 W into 8 Ohms (20 Hz - 20 kHz).
Music Power: 2x 90 W into 8 Ohms and 2x 145 W into 4 Ohms (measured at 0.05% THD).
Circuit: Pure complementary OCL topology (Output Capacitor-Less) with full DC stage; preamplifier and driver in Class A, output stages in Class B.
Distortion (THD/IMD): 0.05% at nominal power (1 kHz) and 0.02% at 50 W (1 kHz).
Frequency response: 10 Hz - 100 kHz (+0 / -2 dB) for the power amplifier; 5 Hz - 70 kHz (+1.5 dB) for the preamplifier.
Damping factor: > 50 into 8 Ohms (1 kHz).
Signal-to-noise ratio: 100 dB (power section); 90 dB for lines and 70 dB for the phono (MM).
Preamplifier Section and Input
Line inputs: Sensitivity 150 mV / impedance 47 kOhm for AUX, TUNER, TAPE 1/2 and DIN 1/2.
Phono inputs (MM): Two adaptable inputs; Phono 1 at 2.5 mV with selectable impedances (22, 47, 100 kOhm); Phono 2 at 2.5-5 mV / 47 kOhm.
RIAA Curve: Deviation of ± 0.3 dB between 20 Hz and 20 kHz.
Tone Control: Selectable cuts for bass (100 Hz or 50 Hz) and treble (10 kHz or 20 kHz) with ± 10 dB range.
Filters: Low cut at -3 dB at 10 Hz (12 dB/oct) and High cut at -3 dB at 20 kHz (6 dB/oct).
Components and Dimensions
Components: 39 transistors, 8 FETs, 2 integrated circuits, 25 diodes, 1 LED.
Power supply: Three independent transformers; total capacitance of the main capacitors 13,600 µF; maximum power consumption 520 W.
Dimensions: 442 x 144 x 363 mm (W x H x D).
Weight: 16 kg.
The amplifier shows some normal signs of time but is overall perfect despite its age. I personally used this amplifier until a few weeks ago. I’m also attaching demonstration videos.
In the video you’ll also see the Optonica ST-1616 tuner, which I would love to sell in combination with the amplifier. If purchased together I could consider possible shipping arrangements.
The amplifier will be shipped with proper protective packaging.
Video link 1: https://youtu.be/sO_LV9WTloI
Video link 2: https://youtu.be/Kf3B895ik2w
In this listing only the amplifier is for sale. The Optonica ST-1616 tuner is for sale in a separate auction here on Catawiki as well.
This is a private sale without warranty. Please check the images before purchasing.
I propose a fantastic Optonica SM-4646 amplifier, an elegant, all-black model, a historic piece from the Sharp/Optonica high-end series. The black series was considered the “design” version for this amplifier.
Superb, dynamic, and powerful sound, ideal for those seeking vintage audio quality without compromise. The unit is perfectly functional and in excellent condition. The volume knob was restored a few days ago, removing scratches from the surface.
Awarded in 1977 with the prestigious French Laurier d’Or (Golden Laurel) for “exceptional functionality, design, and performance,” a recognition reserved for the best audio products of the era.
The amplifier features three power transformers for “Delta Power,” DC current stages in Class A (preamplifier + pre-driver), two large main capacitors of 13,600 µF, low-noise FETs and differential amplifiers, a 4-way volume attenuator, and a total weight of 16 kg.
The center transformer powers the preamplification and driving stages in Class A, while the other two, independently, power the left and right output stages in Class B.
From the outside it doesn’t look like that, right?
Indeed – but either it wasn’t enough to climb to the top tier of the market, or it was too much to keep prices affordable and secure a solid position in the mid-range.
Esthetically it looks a bit heavy and clearly leans toward the 60s rather than the budding 80s. Which is quite fascinating.
Main Technical Specifications
Output Power (RMS): 2x 70 W into 8 Ohms (1 kHz, 0.05% THD) and 2x 95 W into 4 Ohms (1 kHz, 0.05% THD); 2x 60 W into 8 Ohms (20 Hz - 20 kHz).
Music Power: 2x 90 W into 8 Ohms and 2x 145 W into 4 Ohms (measured at 0.05% THD).
Circuit: Pure complementary OCL topology (Output Capacitor-Less) with full DC stage; preamplifier and driver in Class A, output stages in Class B.
Distortion (THD/IMD): 0.05% at nominal power (1 kHz) and 0.02% at 50 W (1 kHz).
Frequency response: 10 Hz - 100 kHz (+0 / -2 dB) for the power amplifier; 5 Hz - 70 kHz (+1.5 dB) for the preamplifier.
Damping factor: > 50 into 8 Ohms (1 kHz).
Signal-to-noise ratio: 100 dB (power section); 90 dB for lines and 70 dB for the phono (MM).
Preamplifier Section and Input
Line inputs: Sensitivity 150 mV / impedance 47 kOhm for AUX, TUNER, TAPE 1/2 and DIN 1/2.
Phono inputs (MM): Two adaptable inputs; Phono 1 at 2.5 mV with selectable impedances (22, 47, 100 kOhm); Phono 2 at 2.5-5 mV / 47 kOhm.
RIAA Curve: Deviation of ± 0.3 dB between 20 Hz and 20 kHz.
Tone Control: Selectable cuts for bass (100 Hz or 50 Hz) and treble (10 kHz or 20 kHz) with ± 10 dB range.
Filters: Low cut at -3 dB at 10 Hz (12 dB/oct) and High cut at -3 dB at 20 kHz (6 dB/oct).
Components and Dimensions
Components: 39 transistors, 8 FETs, 2 integrated circuits, 25 diodes, 1 LED.
Power supply: Three independent transformers; total capacitance of the main capacitors 13,600 µF; maximum power consumption 520 W.
Dimensions: 442 x 144 x 363 mm (W x H x D).
Weight: 16 kg.
The amplifier shows some normal signs of time but is overall perfect despite its age. I personally used this amplifier until a few weeks ago. I’m also attaching demonstration videos.
In the video you’ll also see the Optonica ST-1616 tuner, which I would love to sell in combination with the amplifier. If purchased together I could consider possible shipping arrangements.
The amplifier will be shipped with proper protective packaging.
Video link 1: https://youtu.be/sO_LV9WTloI
Video link 2: https://youtu.be/Kf3B895ik2w
In this listing only the amplifier is for sale. The Optonica ST-1616 tuner is for sale in a separate auction here on Catawiki as well.
This is a private sale without warranty. Please check the images before purchasing.
Details
Era
1900-2000
Brand
Optonica
Model
SM-4646 HB
Multiple models
Yes
Physical condition
Excellent
Number of objects
1
Includes
Power cord
Serial number
80801849
Year of manufacturing
1979
Weight
16 kg
Functional condition
Tested and working/playable
Height
14 cm
Width
44 cm
Depth
37 cm
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