Kenwood KD-650

The Kenwood KD-650 is a great turntable. It was very good back in 1978 when it was made, and it is very good today. It’s a Quartz Phase-Lock Loop, direct-drive, 2 speed (33 and 45), fully manual turntable. It retailed for $400 when new and was a big seller for Kenwood. The Kenwood line also featured the KD-550, KD-750, and KD-850. The KD-X50 line came with a tone arm while the KD-500, KD-600, and KD-800 did not. It was basically a $50 difference in price as the KD-600 without a tonearm retailed for $350.

While the base may look like fake granite veneer, it is far from it. A properly engineered base can dramatically reduce or eliminate resonance and different materials will damp at different frequencies. Kenwood decided to use a double construction method which would absorb resonance through the entire frequency range. This double construction consisted of a main top layer of ARCB resin-concrete and a bottom layer of hard homogenized compression board. Bonded together these two layers form a compact, rigid structure able to damp resonance over the entire frequency range. The top layer is composed of limestone particles, glass powder, and polyester resin. This combination absorbs low frequencies effectively. The bottom layer of compression board absorbs the higher frequency resonances.

The KD-650 has a high-inertia platter weighing 5.7 pounds (2.6kg) with a diameter of 13 inches (33cm). Its high inertia makes it capable of resisting or absorbing any external influences such as pivot bearing friction, motor or transformer vibration and/or sound pressure waves generated from speakers. Below is a scope trace showing the platter absorb a shock. The Kenwood platter is on the left while a conventional platter is on the right.

The stock S-shaped, static balanced, oil-damped tonearm on the KD-650 is extremely well designed and even incorporates a hand-made brass pivot bracket to reduce tracking error. It is slightly longer than most tonearms at 9 5/8 inches (245mm) long, while other tonearms are around 9 inches. This extra length reduces tracking distortion. Included with the tonearm was a DM-11 cartridge and N-11 stylus. The tonearm has a tracking force range 0-3 grams and cartridge weight range of 2-12 grams. This is the same tonearm that was used on the top-of-the-line KD-850 turntable. In fact, the KD-850 and KD-650 are identical electronically except for the automatic stop/start functions that the KD-850 has. They even utilized the same platter, dustcover, motor, and tonearm.

The KD-650 tonearm has a wide diameter, thick, diecast aluminum base which is attached directly to the ARCB cabinet using machine screws. An anti-resonant hard rubber piece is sandwiched in between.

The KD-600 version came with two tonearm bases for either Ortofon AS-212 MKII, or the Infinity
Black Widow and SME-30091, 300911, 3009111 series laboratory reference tonearms.

As you can see, the tonearm adjustments on Kenwood’s KD-650 are extensive. Tonearm height is adjustable by a smooth operating helicoid mechanism to + or – 3mm. Arm elevation is accomplished via an oil-damped, sealed cueing device to prevent “bounce”. Standard anti-skate adjustment is also available.

Obviously, the KD-650 is an impressive turntable. Did Kenwood stop there? Nope. The wiring inside the tonearm is a special silk-wound, low resistance, parallel Penta-Litz wire, which reduces signal loss, crosstalk, and capacitance. All the contact points are even gold plated. The stock headshell is made of diecast aluminum and utilizes a unitized construction and industrially-derived Collet chuck system to increase rigidity and lower resonance.

Here are the KD-650 specifications:

• Drive: quartz PLL direct-drive system
• Motor: 20-pole 30 slot brushless DC servo motor
• Platter: 33cm, 2.6kg aluminium alloy die-cast
• Speeds: 33.33 and 45rpm
• Wow and flutter: less than 0.025% WRMS
• Signal to noise ratio: more than -75dB
• Tonearm: static-balance type, s-shaped pipe arm, eia plug-in connector
• Effective length: 245mm
• Overhang: 15mm
• Stylus pressure range: 0 to 3g
• Usable cartridge range: 2 to 12g
• Dimensions: 19 5/16″ W x 6 1/2″ H x 18 1/8″ D (490 x 165 x 460mm)
• Weight: 33.9 pounds (15.4kg)

Below the power button are digital touch-sensing buttons for speed selection and start/stop. The speed buttons have LED indicators as well.

The KD-650’s Quartz lock indicator lights up when the PLL circuit is locked and the turntable is operating at the correct speed. The speed control system uses a large scale IC that incorporates highly stable MOS FETs so it is unfazed by temperature or moisture.

The motor in the KD-650 is a classic example of over-engineering. It’s a 20-pole, 30-slot brushless DC motor that provides the very high torque needed to move the heavy platter. Together, the motor, platter, and PLL circuit in the KD-650 combine to produce extremely low wow and flutter (0.025% (WRMS)).

What else does the Kenwood KD-650 have?

• Electronic controlled braking system
• Special anti-vibration rubber platter sheet
• Illuminated quartz lock indicator
• Illuminated power indicator
• Audio insulators
• Heavy duty ribbed non-resonating acrylic dust cover
• Low-capacitance RCA cables

Does the KD-650 have any weaknesses? Well, the heavy dust cover puts a strain on the hinges and they tend to fail over the years, so many KD-650’s are missing their hinges. The touch sensitive speed controls occasionally fail as well and are not easy to fix. But, overall, the KD-650 is well laid out inside with just two circuit boards and is easy to work on.

Should you buy a Kenwood KD-650 if you have the opportunity? Absolutely. If it’s in good working condition it will be one of the best turntables you’ll find. To match it’s specs in a modern day turntable you’d have to spend ridiculous money. The top-of-the-line KD-850 is just as good and is fully automatic but you’ll rarely see one for sale. The KD-650 is easier to find but still not common. I guess most of their owners just don’t want to sell them and I can’t blame them. The styling and performance of the Kenwood KD-650 is really hard to beat.