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.

Back to the Future: AR XA + NAD 3020

Whenever I find them at reasonable prices, I re-acquire audio components I owned and enjoyed in the 80s. I started my quest with the Grace G707 tonearm, a TDA1541-equipped Magnavox CDB 473 CD player and the dynakit stereo 35 PP EL84 power amp. I also tried to rekindle my affection for the BBC LS3/5A monitor and my MC SUT collection now includes a pair of Sony HA-T10s. Meanwhile, I've been hunting for an AR XA turntable and a first generation NAD 3020 to complete my journey back in time.

A Visit to VAS Audio - SPU-G, Miyabi & Ikeda

 

During a recent visit to Steve and Ray at VAS Audio, my attention was caught by an amplifier I built in the early 2000s. This is one of the very few I released into the wild.

AliEx amorphous, Hashimoto HL20K6 + Sony TamRadio line output transformers

L>R: 6AH4 + AliEx, 12B4A + Sony/Tamradio and 6AH4 + Hashimoto HL20K6

The last time I saw my buddy J-Rob was pre-COVID, but we keep in touch via email and text messages. During one of those hello/how you doin' moments, the chat progressed to line preamp transformers and how the $100/pr. amorphous jobs from AliExpress perform. 

I used to own a pair of Tango/Hirata NP216N nickel line OPTs, which were featured in my Sound Practices issue 17 homebrewer article. In hindsight, I don't think I gave them a fair chance so this was a good opportunity to revisit the topology.

Lycan3R WP12024 Horn

A couple of months after I blogged about the 3D printed prototype of the WP12024 horn, Trieu sent a pair of these beautifully finished cast aluminum production versions. Included in the package was a set of parts for a horn stand patterned after the Western Electric original I've only seen in Stereo Sound Tube Kingdom.

Two RCA derived octal phono preamps

Keen-eyed readers and visitors to my YouTube channel may have noticed the two octal phono preamps I've been using in my recent uploads. I built them for the following reasons:

1. Although the Loctal EAR 834P had no problems driving the Intact Audio nickel autoformers, the 5k Ohm output Z of the Shure M65 phono preamp sounded very anemic.
2. In the spirit of not leaving stones unturned and my curiosity for other sonic flavors notwithstanding, I looked back to passive RIAA EQ phono circuits I've been wanting to build, which have low enough output impedance to drive an Autoformer Volume Control.

Shielded Finemet FM-MCT1 MC Step Up Transformers

 

It's been almost a year since my favorable review of this Finemet MC step up transformer. Overall, it has given me great musical pleasure! However, when tasked to amplify MC phono cartridges with lower output than a typical Denon DL103, in particular the Ortofon SPU and Fidelity Research FR1 MkII, hum could be intrusive in softer passages of classical music, especially when not carefully sited away from motors and power supply transformers.

As I had suspected in my initial review, the FM-MCT1 wasn't as well shielded as the Hashimoto HM7, Tamura TKS83, Altec 4722 and other vintage MC SUTs in my collection.😔 Now, I had no recourse but to compromise my aesthetic preference for an open chassis in favor of an enclosure to provide additional shielding.

Silbatone Box Adventures

from Western Electric Oscillator July 1947

Whether it's an open baffle as conceived by G.A. Briggs or an enclosed box like the Western Electric utility boxes above, I've always been an advocate for a wide baffle design. The wide frontal area serves as an acoustic reflector that helps propagate sound toward the listener instead of escaping to the sides and back. Somehow the wide baffle, whether open or closed, always makes reproduced music sound more alive to my ears!

A notable exception is the narrow front baffle Silbatone box designed by Dr. Stefano Bae for the Western Electric/Altec 755A. Since I uploaded the cabinet project under the auspices of Joe Roberts, it has garnered a following amongst DIYers who've reported successful results mounting other 8' drivers like the Altec 755C, 755E and the Lafayette SK98/Pioneer PIM8L. 

I finally got a chance to mount and listen to my 755Cs and PIM8Ls + other 8" wide band drivers. Hopefully, this article will encourage readers to DIY this mini-monitor sized box because it really offers a lot of musical pleasure per cubic inch!

To recap, let's start with the...

SETUP 2024

Single Ended Triode Users of the Philippines 2024

At the dawn of the 21st century, I uploaded hifi systems owned by audio buddies who had been inspired by the Sound Practices ethos. These were the guys who originally coined SETUP. After a couple of decades, the number of Filipinos who indulge in this hobby has increased exponentially.

Here's what I saw and heard during my recent visit.😊

Harana Audio Workshop

Altec 311-60 horns + 288 drivers with Fostex super tweets on top of a pair of Harana V-Vent bass bins with partial horn loading

Finemet FM-ATVR1 + Intact Audio Nickel 28-step Autoformer Volume 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.

OJAS 529B Horn

During my visit to the OJAS listening room late last year, Devon asked me to evaluate a pair of horns OJAS developed in collaboration with Lycan R&R. The OJAS 529B is a 500 Hz horn rescaled from the large format Altec 329A for use with 1" format Altec/GPA compression drivers.

  This horn was designed with a throat inspired by the Western Electric 32 horn to avoid the harshness and distortion I (as well as others 😉) associate with the Altec 811 and 511 horns, 

For more details about this horn's evolution and construction, please click here.

SE171A Amp Remastered

My dad would've turned 97 today. To celebrate his birthday, the video clip above features a recording of his favorite violinist, Nathan Milstein, playing Presto from Bach's Sonata No. 1 in G minor for unaccompanied violin. While he was doing post-graduate studies at The Juilliard School in the mid 50s, he was fortunate to have attended concerts of the great violin virtuosos of that era - Jascha Heifetz, David Oistrakh, Nathan Milstein, etc.

He would later recount that Nathan Milstein's performance of the Glazunov violin concerto was the most unforgettable! Even if he never got a chance to add this violin concerto to his repertoire, he conducted the Manila Chamber Orchestra with me playing the Glazunov violin concerto in 1987. The music of the slide clip above is the middle movement from our performance.

Before I bore everyone reminiscing about my dad and our life as musicians, let's get on with the subject at hand. The amp featured in this upload uses a directly heated triode power tube that was introduced around the time my dad was born.

Line Transformers for Digital Audio

Altec 15356 + UTC A20

While browsing at Books Kinokuniya in NYC in the 90's, this Noguchi ad from the November 1994 MJ Audio Technology issue inspired me to experiment with line transformers as digital sound enhancers. Since I was living on a post-grad assistantship budget back then, importing this pair from Japan was out of the question.

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.

JE Labs Man Cave 2024

This is the side of the man cave where I spend a lot of time listening and evaluating new projects.

In the coming months, I will be talking about phono preamps, autoformer volume control, revisit the transformer coupled line stage topology, SE amps, etc. I will also continue my classic Japanese idler-driven turntable series, feature a couple of SE-DHT amp-friendly drivers + more.

Most of the audio components listed below are hyperlinked if you mouse over the text. Those that are not will be linked once the article is uploaded.

I like to taste new sonic flavors that are within the DIY realm😊

JEL man cave tour