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.

Minimalist Twin-Armed Thorens TD124

Ever since I left this twin-tonearm compatible TD124 plinth in the attic, I've been trying to find the simplest way to use two tonearms on this turntable.

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.

Finemet FM-MCT1 MC Step Up Transformers

Looking back to my late 90s home brewer article for Sound Practices issue 17, I noticed that a good number of components in my hifi system then are still serving two and a half decades later. The Tamura TKS83 moving coil step up transformer is one of them.

After building a hifi system for my cousin during lockdown, the Hashimoto HM7s made me realize that while the Tamura TKS83s can equal the HM7s in terms of bandwidth, the TKS83s can sound mechanical. It also became apparent that there are areas in which the classic Altec 4722s and 15095As can be improved upon.

When I finally heard a pair of Peerless 4629s, I was very impressed by their uncanny ability to reproduce very lifelike 3-dimensional vocals. However, I was quite disappointed when I played anything greater than a string or jazz quartet because the sound started getting mushy and dynamically compressed. 

Overall, my ears still prefer the smaller and more affordable brother, the Altec 4722!

During the most recent Kutztown radio meet, John Piro handed me this finely crafted wooden box to audition. As mentioned in my Kutztown coverage, a good friend from Manila, Tony, aka Mr. November HiFi Show, scheduled his visit so we can hunt for tubes, parts + LPs. 

Upon our return from the expedition, a sumptuous dinner prepared by Tish + a bottle of Ripasso awaited us. We capped the evening by hooking this wooden box to my hifi. Our jaws dropped each time we played an LP!

Housed inside the box is a pair of Finemet FM-MCT1s! 

In the ensuing days, I did further evaluation and indeed, these Finemet MC transformers are doing something extra special. My only reservation was, in spite of the potted construction, the FM-MCT1s are more susceptible to hum induction compared to the Altecs and Tamuras. Even if John lined the wooden box heavily with copper shielding, I still had to keep them away from power transformers, AC motors, etc.

Inspired by the sonic niceties I heard, I was undeterred so I contacted Mr. Kimura of General Transformer Sales Co. Ltd. After a few emails aided by Google translate, I finalized my order. 

Gtrans.co.jp is headquartered in the same location as the former Noguchi store we visited in 2015, which is in the basement of Tokyo Radio Department Store in Akihabara.

Kimura-san specified a 3-4 week window for delivery. So I downloaded the spec sheet, studied the schematic and ordered a cast aluminum project box from Amazon.

Within 18 days, the transformers were at my doorstep.👏

Finemet FM-MCT1

These are very well made and quite hefty! They're heavier than the TKS83s which, if memory serves me right, are about the same weight as the HM7s.

 

I chose a different layout for the 145mm x 121mm x 40 mm MC step up transformer chassis for neater routing of RCA cables.

Under the hood

 

The input and output RCA jacks are on the backside mounted on top of the chassis. Only the ground lug was mounted on the side.

I installed the 3-position gain/impedance load selector in front of the chassis.

No matter which cartridge I used - Denon DL103, -R, -C1, Fidelity Research FR1 MkII, Ortofon SPU #1s, -G, -GM, Supex SD900, etc. - male and female vocals + instruments are portrayed with 3-D presence and realism in a deep and wide sound space. The musicians are in my man cave!

Boosted by the Finemets, even the most analytical and dry-sounding MC cartridges in my stash, like the Goldbug Clement II and Sony XL44 came to life with more warmth. If that's a coloration, it's certainly most welcome!

  

These Finemet MC transformers seem like they were configured to resolve every note in the complex musical score and massive instrumentation of late romantic symphonies along with the wide range dynamics from pianississimo to quadruple fortes inscribed therein by the composer. They also excel in reproducing the ambience, airiness and spaciousness of the concert hall's acoustics embedded in well recorded LPs.

I finally found a pair of MC transformers which combine the organic midrange and harmonious richness of classic vintage iron + the wide bandwidth, detail retrieval, and dynamic range of modern magnetics!

Ever since I became an audio DIYer, I pride myself in not being impulsive about upgrading components in my hifi. This is a rare exception!😉

CODA

As luck would have it, last week we had a family get together because a cousin based in Tokyo was visiting and brought some goodies!

Stereo Sound
Tube Kingdom Volume 104

If I got it right, in this survey of commercially available MC step up transformers, the Finemet FM-MCT1 was the only DIY unit.

Despite the wacky nature of the Google translate app, the gist comes across as quite positive!

Enjoy browsing the magazine to Bobbi Humphrey's tune spinning on a Garrard 401 + AB309 tonearm with a Supex SD900 boosted by the Finemet FM-MCT1s!✌

Click here for the shielded version update!

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! 🎶

Cork Turntable Mat

 

 Rubber hardens as it ages and this is exactly what happened to the rubber mats originally supplied with my Garrard 301, 401, Thorens TD124 and other turntables. I'm aware that modern reproductions are available, but I wanted something more affordable and practical. So I surfed and found a 3-pack cork mat with an LP label indentation for $12 on Amazon.

Does this mat make the sound better?🤔 Hmm...frequent visitors to this blog know better that after several decades in this hobby, I've grown averse to typical audiophile hair-splitting.😉

However, I'm happy to report that a few LPs from my collection which are slightly dished or warped now lie flat. That's good and I like the sound.

Try it and hear for yourself!😊

Happy Spinning!🎻🎷🎶

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!