Japanese Idler-Driven Turntable Part 7: Kenwood PC350

Kenwood PC350 - a Japanese TD124 spinning a jazz tune!😉

This ca. 1969 Kenwood turntable adapted the Thorens TD124 drive system sans eddy current speed control.

Japanese Idler-Driven Turntable Part 6: Realistic Mark 8

Just like cars, a new turntable model has to be introduced every year or two to keep consumers' interest and convince them that newer is better.😊

from page 37 of the 1960 Radio Shack Catalog

The Realistic Mark 8 improved upon the similar looking "motor unit-stye" Mark 7 in Part 4 of this series by adding a 16 rpm speed and supplying a half pound heavier cast aluminum platter.

Japanese Idler-Driven Turntable Part 5: Lafayette PK300

I bought this Lafayette PK300 idler-driven turntable because it looked like an improved Shield MO-19 (aka NEAT P58H) with the added feature of an eddy current pitch control as found in the Garrard 301/401 and Thorens TD124.

Shield MO-19 vs. Lafayette PK300

Comparing them side by side, the PK300 turned out to be proportionately smaller in all dimensions and lighter in weight. Hmmm🤔…let's travel back to the late 50s.

Japanese Idler-Driven Turntable Part 4: Realistic Mark-7

Here's a tale of two idler-driven turntables of Japanese origin sold by Radio Shack in the late 50s. They share the same model badge and engineering features but they aren't exactly twins.🤔

This turntable/tonearm combination has been in my collection for over twenty years. I wired the tonearm for stereo because I particularly enjoy using it with the Shure M3D and M7D. 

I couldn't find this in any of the Radio Shack Catalogs issued from the late 50s to the early 60s unless it escaped my tired, old eyes.  

from page 2 of the 1957 Radio Shack Sale Flyer

However, the A-3 tonearm, which is essentially a Calrad SV12/Musicmaster Model 12/Velvet Touch sibling, was featured in the 1957 sale flyer above.

from page 4 of the 1958 Radio Shack Sale Flyer

This is the Mark 7 turntable recorded in the Radio Shack Catalog Vault. 

Based on the shape of the chassis, this Mark 7 is perhaps the younger of the two since it looks very similar to the succeeding Mark 8, which I will discuss in a future installment.

DIFFERENCES

Although not quite as heavy and massive as a QRK or Russco, the cast aluminum chassis is very rigid on both units. The earlier MK7 chassis above is configured to accommodate a 9"-10" tonearm, while the later MK7 below was designed as a "motor unit" like the Garrard 301 and 401.  

The speed selector linkage to the idler wheel in both are similar, but due to a slight difference in the motor mounting layout, the idler arm and idler wheels are not interchangeable.

SIMILARITIES

Except for the paint color, this hysteresis motor is exactly the same unit fitted to my NEAT P58H, which I covered in Part 2 of this series. Click here for motor servicing information.

The main bearing is an oil lubricated design, which supports a 3-lb. cast aluminum platter.

MODs & TIPs

Before moving on, the younger MK7 depicted above had a serious issue - the motor has a bent rotor spindle!😔 Will I be able to save it by adapting the motor from another Lafayette PK245 (don't ask my wife how many turntables I own 😆) with a warped platter?🤔 

While planning the motor transplant, I examined the MK7 idler wheel condition and decided it might be worth rejuvenating.

So I mounted it on a handheld drill, deglazed the rolling surface with 400 grit sandpaper, and soaked it in brake fluid for over a week. This was suggested to me decades ago by a kind soul who visited the Rek-O-Kut Tips page in my old website. It has worked with two other Japanese idler wheels but I've never tried it on a Lenco or Rek O Kut. Back in those days, it was more convenient to just send Lenco and ROK wheels to Ed Crockett, RIP 😞 or Terry Witt 👍, who's still catering to the needs of audio DIYers.  

The above idler wheel was resurfaced by Gary of VoM. 👍

 Even if the rubber motor mounts were still supple, I replaced them with springs. A nice lesson I learned from servicing my NEAT P58H.

 To my ears, the spring mounted motor + 8 mm ball bearing/nylon countersunk washer thrust pad help lower the noise floor.

Realistic Mark 7 stepped pulley specs

Dynax P-9

These pics were sent by a blog reader. 

It is essentially the Realistic Mark 7 above with a different inscription on the badge.

MUSIC VIDEOS 😉

I have a close affinity for the Mark-7 + A3 since this was the very first Japanese idler-driven turntable I acquired.

Turntable: Realistic Mark 7 + A3 viscous damped tonearm

Phono Cartridge: Shure M7D

Phono Preamp: DIY 6J7 + passive RIAA EQ + 6SL7 + 6SN7 cathode follower

Line Stage: JE Labs Loctal

Amp: Radiotron SE2A3 with Finemet FM-6WS OPTs

Speakers: Altec 406Zs in Coronado cabinets + Azzolina Audio KS12024 horns + Altec 806A

drivers

Turntable: Realistic Mark 7

Tonearm: Tokyo Sound ST900

Phono Cartridge: Ortofon SPU #1s

MC Step Up: Tamura TKS83

Phono Preamp: DIY 6SL7 split/passive RIAA EQ + 6SN7 cathode follower

Line Stage: JE Labs Loctal
Amp: JE Labs Simple 45 w/ Tamura F475 OPTs

Speakers: Altec 406Zs in Coronado cabinets + Azzolina Audio KS12024 horns + Altec 806A drivers

Turntable: Realistic Mark 7 + A3 viscous damped tonearm

Phono Cartridge: Shure M7D

Phono Preamp: DIY 6SL7 split/passive RIAA EQ + 6SN7 cathode follower

Line Stage: JE Labs Loctal

Amp: JE Labs SE171A with Tango H5S OPTs

Speakers: Altec 406Zs in Coronado cabinets + Azzolina Audio KS12024 horns + Altec 806A drivers

Enjoy! 🎶

Japanese Idler-Driven Turntable Part 3: Lafayette PK245

 

Page 12 of the 1958 Lafayette Radio Catalog

This is a Lafayette branded turntable manufactured by Teac of Japan in the late 50s. The drive system is an innovative implementation of the basic Rek O Kut L34/37 Rondine Jr. design.

PK245 + Musicmaster Model 12 + GE VRII

I got this unit with pulverized motor mounts.

Since the original motor mounts are no longer available, I had to improvise by using rubber grommets... 

...and 1/2" x 0.72" 302 stainless steel springs 😊 from Grainger. IIRC, it was part number 1NDJ1.🤔

!!!UPDATE!!!

After further listening tests, I determined that the rubber shock mounts used in the Gray Research turntable were better suited to this design. They can be sourced from Surplus Sales of Nebraska, part number RPS 426-0001.

PK245 + Musicmaster Model 12 + GE VRII 

 The main bearing isn't as substantial compared to the Rek O Kut.

However, the captive bearing is highly polished and the threaded bottom cap houses a hardened gun metal blue thrust pad.

I used SAE 30 non-detergent oil for the main bearing and "Blue" 3-In-One for motor lubrication.

The aluminum platter is a little over 3 Lbs.

This hysteresis motor is similar to the unit fitted to the NEAT P58H. Please click here for full details on servicing that motor and etc. 

The pictures below highlight features unique to the PK245.

Top shell motor bearing reassembly sequence

The bottom shell motor bearing reassembly is exactly like the top shell except for the motor shaft terminating with a 3mm ball bearing on a thrust pad as shown above.

Motor wiring schematic

PK245 + Musicmaster Model 12 + Denon DL102

Gary at The Voice of Music refurbished the idler wheels above.

Idler wheel components

Reassembly sequence

Top = 78 rpm idler wheel + arm

Bottom = 16/33/45 rpm idler wheel + arm

Idler wheel reassembly sequence

60 Hz pulley dimensions + click here for more details regarding motor pulley alignment.

PK245 + Grace G540L + Ortofon SPU#1s

Happy tinkering and listening!

Japanese Idler-Driven Turntable Part 2: NEAT P58H/Shield MO-19

In the early 2000s, the swinging tonearm mount of the Shield MO-19 caught my attention because it looked like the perfect partner for my Velvet Touch viscous damped tonearm. It turned out that this Japanese 4-speed idler-driven turntable is actually a rebadged NEAT P58H. 

Its performance exceeded my expectations! So instead of relegating it exclusively for mono hifi playback duties, I also enjoy using it fitted with high quality tonearms like the Audio-Technica AT1501-II, Denon DA305, Grace G540L, Fidelity Research FR54 and others for stereo LPs.

I got this NEAT P58H + Tokyo Sound ST900 tonearm when Tish and I returned to the States in 2016. It wasn't as well kept as the MO-19 and required a bit more fettling. 

The turntable is built on a heavy duty cast chassis with a 1.5 kg cast aluminum platter. Aside from a few discussions in audio forums, the only literature I've found about this particular model is the 1960 NEAT catalog available for download at vinylengine.com.

Everything I've done to my NEAT P58H and Shield MO-19 is documented below. 

Idler wheel + idler arm

The rubber on this NEAT P58H idler wheel was in good condition except for a pinch, which couldn't be removed by minor grinding. So I sent it to Terry E. Witt for new rubber.

Terry of Terry's Rubber Rollers did a great job rejuvenating the P58H idler wheel (above left) + another wheel for my ROK L34 Rondine Jr. 

Idler wheel installation sequence

The idler wheel should spin freely and quietly after a drop or two of blue 3-In-One SAE 20 motor oil. 

Idler arm reassembly sequence

The idler wheel arm action should be snappy. If it isn't, back off the nut a bit and/or add a bit of light oil to the sliding surfaces.

A good balance between speed accuracy, torque, and low noise can be achieved by adjusting the idler wheel contact pressure to the inner rim of the platter.

Unplug the turntable from the AC source and manually spin the platter CW or CCW. The platter should gently stop when the speed control knob is turned to any of the speed settings as the idler wheel engages the inner rim of the platter. If the platter stops abruptly or doesn't stop at all, go back to the preceding procedure and adjust the idler wheel position on the idler arm accordingly.

60 Hz pulley dimensions +

red arrow indicates the pulley's set screw for height adjustment

While the turntable is disconnected from the AC source and the speed selector set at 33 rpm, I set a 1-1.5mm clearance so that the idler wheel doesn't touch the shoulder of the 45 rpm step.

Speed Selector Mechanism

With the speed selector at the 78 rpm setting, make sure there's no clearance between the tip of the set screw and the piston which raises and lowers the idler wheel arm mechanism.

Before we move on, how about a track from Style Council?

Motor

The turntable is powered by a fairly substantial 4-pole hysteresis synchronous motor. 

It's not as hefty as American-made Ashlands and Bodines, but bigger than the TD124's E50 and comparable to those fitted to the Garrard 301, 401, and the ROK B12GH's Papst Aussenläufer. 

 Through the years I've gotten requests for a schematic because some of these turntables were hastily pulled out of installations by flippers for quick bucks on eBay. 

Spring suspended motor = less vibration

Top view of the motor + sub-chassis

The deteriorated bottom rubber mounts (red arrows) can be replaced with rubber grommets. 

To remove the motor, unsolder the motor wires from their respective connections. Use my hand drawn schematic above as a guide. Then, remove the four nuts marked with blue arrows.

Before pulling out the motor entirely, I marked its orientation (black arrows) in the sub-chassis for easier reassembly.

To disassemble the motor, remove the four nuts marked by the yellow arrows.

Motor parts ID

The top and bottom shells house the sintered bearing well and are almost identical in construction except for an exit hole on top for the motor spindle. I marked the partially visible sintered bearings (or bushings) with blue arrows. To access the bearings for cleaning, remove the spring clips marked with green arrows. 

As shown in the picture above, the bottom shell has a thrust pad. I clean sintered bearings by soaking them in solvent, either lighter fluid (Naphtha) or isopropyl (91% or greater) alcohol (IPA) overnight. For lubrication, I use blue 3-In-One SAE 20 motor oil. 

The parts inside the bearing well are numbered in sequence for reassembly.

To access the motor bearing, remove the bottom cover, which is held by three small screws + lock washers. Be careful not to lose the tiny 3mm ball bearing. Clean all the components with either Naphtha or IPA. The numbers indicate the sequence for reassembly.

The motor should now be whisper quiet in operation.

Let's take a break and hear a tune from Sinatra at the Sands LP.

Main Bearing

Just like the Shield MO-19, I also found old grease at the end of the threaded bottom cap of the main bearing of the P58H. The lack of an oil seal in the threaded bottom cap further confirms that this is a grease bearing design.

These are the main bearing components after cleaning (soaked in solvent overnight). They're ready for fresh grease and reassembly. I used Phil Wood grease left over from my Raleigh 20 restomod folding bike project. 

The Garrard 301 grease bearing makes the NEAT P58H bearing look diminutive.

CODA

Although innovative in its own right, the various pictures show that the mechanical design and manufacturing quality of the NEAT P58H/Shield MO-19 isn't quite as sophisticated as the illustrious Garrard 301, 401, or Thorens TD124. I never envisioned it to equal those revered models in terms of performance. However, IMHO and experience, a reconditioned NEAT P58H is a worthy alternative to a restored Lenco or Rek O Kut.

A nice ballad from Dexter Gordon's album Go brings us to a close.

HAPPY LISTENING!

Back to Part 1