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Sony TA-4650

Stereo Integrated Amplifier (1975-77)

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Sony TA-4650


V-Fet is the acronym for the newly developed vertical type field effect power transistors used in the TA-4650 amplifier.

A V-Fet has extremely low output impedance and excellent high power capability, delivering an output current proportional to input voltages and assuring virtually distortion free amplification.

Use of the V-Fets in the power output stage results in a quality of reproduction hitherto not available to audiophiles.


Power output: 30 watts per channel into 8Ω (stereo)

Frequency response: 10Hz to 100kHz

Total harmonic distortion: 0.05%

Damping factor: 45

Input sensitivity: 2.5mV (MM), 150mV (line)

Signal to noise ratio: 70dB (MM), 90dB (line)

Output: 150mV (line), 17mV (DIN), 1V (Pre out)

Speaker load impedance: 4Ω (minimum)

Semiconductors: 6 x VFET, 4 x FET, 36 x transistors, 26 x diodes

Dimensions: 460 x 168 x 323mm

Weight: 12.4kg


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Reviewed Sep 07th, 2017 by padg1956

I bought my TA-4650 three years ago brand new after 'loft-find' in an old electronic store, completely boxed with all papers etc.
The owner was forgotten the Sony for almost 40 years...
I love the machine and moreover I love the great warm sound!
I'm very, very happy!!!

Reviewed Aug 30th, 2017 by hifiramr

Its a gem used many hi end new gen amps but this one is extra ordinary.Excellent sound stage with stunning details.Its very hard to believe an old vfet sony amp provide such a magical sound.

Reviewed Mar 07th, 2015 by ravenman

Typical SONY quality and innovation from that era, for VFETs, very reliable and cold, amplifier driving my modern high-end speakers and sounds fantastic with external PRE-AMP. Sound is very detailed, warm, slow without technical transistors sound even with class A

Reviewed Mar 30th, 2012 by cgutz

Love my old Sony VFET TA 4650. Bought it in 1980, still using it in my primary system.



re: TA-4650

This my first machine to V-FET world, very neutral well detailed reproduction without any colorations, for that era absolute amazing technology. 4650 preamplifier is not very highfidelity in mind (adds some lowend coloration and cut some fine details), not big problem, with external highend preamp is sound to heaven.

Sony TA-4650

Produced from 1974 to 1978, this Service Manual is from 1975.
My example serial # 805653 has in the phono section 2SK79 low power V-Fet's. In case of an overhaul the diodes D302, D352 and the D414 should be replaced with two serial connected silicon diodes, like the 1N4148. The D302/352 are thermally connected to the transistors Q307 and Q357. There after the bias should be readjusted. The 75mV mentioned in the manual for the bias value is probably to high. It would result 2x159mA bias current and a total of 27W dissipation. Try to adjust the bias so at the heath sink temperature is ca. 25-30 celsius above the ambient temperature. The heath sink size (19x12x4.5cm) is shorter (-5cm) than the TA-5650s, but a bit taller, also the 4650 missing the chimneys over the heath sinks. The speaker connectors are the simplest but most reliable ones of the three amps ,the TA-8650 being the worst of this regard (falling a part).

This website is not affiliated with or sponsored by Sony. To purchase TA-4650 spares or accessories, please contact the company via their website or visit an authorised retailer.