Gray Research HF500 Turntable + 108C Tonearm

My buddy John Piro has a knack for finding obscure vintage hifi pieces and has built up quite a collection. A couple of summers ago, he offered his spare blonde plinthed HF500. 

I had just acquired my first and only genuine Gray Research 108C viscous damped tonearm and couldn't pass up the opportunity to pair them up. 

Capstan Drive

The Gray Research HF500 turntable employs a unique drive system. Strictly speaking, it is not an idler drive. A round section rubber belt is partially embedded around the outer rim of the platter, which is driven directly by the motor shaft. Capstan drive is probably a more appropriate technical term.

45 + 78 rpm capstans

To change speeds, the corresponding 45 or 78 rpm capstan (or bushing as termed in the manual) is placed over the native 33 rpm motor shaft.

D&R turntable drive system
Courtesy of jamesvanarsdale.com

 AFAIK, the only turntable from this era which also drove the outer periphery of the platter is the equally rare D&R turntable, but as depicted above, it uses a rubber idler wheel. 

Seiko-Epson drive system
Courtesy of audio-heritage.jp

The Gray Research capstan drive may have been the inspiration for Mr. Takeshi Teragaki's three turntable designs for Seiko-Epson - ∑2000, ∑5000 and ∑5000II.

Servicing Tips

Download a pdf file of the Gray Research HF500 Manual for more detailed information.

This iron platter/bearing combination weighs close to 20 lbs. The 1" spindle tapers to 13/16" which turns on a 1/2" thrust sphere at the bottom of the sintered bearing well. 

After experimenting with a couple of belt sizes, a 3/16" (cross section diameter) x 36" polyurethane round belt x from McMaster Carr, catalog #3044K705 gave the steadiest stroboscope readings at all speeds.

Disassembly

Remove the four screws as indicated by the red arrows. 

The plinth lifts from the bottom frame. 

The top plate is a massive 1/4" thick metal resting on rubber pads at each corner. Prior to installation of new rubber pads, motor vibration could be felt at the tonearm finger lift.

 With new rubber pads installed (+ new motor mounts, see below), vibration was practically nil. The material I used looks very similar to replacement rubber soles used by shoemakers. 

Removing the motor 

To release the motor from the mounting bracket, straighten and pull out the cotter pins.

Left = worn out motor mounts
Right = fresh motor mounts

Another source of vibration were perished motor mounts. Brand new replacements are available from Surplus Sales of Nebraska -  Rubber Shock Mount, Part No. RPS - 426-0001.

 

New rubber mounts installed

Before reassembly, I cleaned the motor and re-lubricated the bearings with blue 3-IN-ONE electric motor oil.

The sound is very energetic!

I've been enjoying my entire mono LP collection! 

View it in action! 😊

Billingham Hadley Pro Small + Leica II Half Case

None of these camera accessories will enhance anyone's picture taking abilities, but talking about camera gear is a pleasant respite from audio.😉

My Olive Billingham Hadley Original has been a loyal companion since the mid-90s. Due to its larger size, it encourages me to bring more gear than necessary. Recently, I got this navy canvas/chocolate leather Hadley Pro Small for moments when I want to travel light. 

A Leica M3 + 35mm and 50mm lens, Fuji X-E3 + lens, a 5 roll film case + other accessories and gadgets easily fit in the small Hadley Pro.

Billingham has tastefully updated a classic!

Leica II half-case

Ever since I restored my Leica II, it's been cradled in a Fed/Zorki half case. Not the most elegant, but it served me well for over 15 years.

Half cases for early Barnack bodies (Leica 0, I + II) sans strap lugs aren't common. I was happy to find a nice one at the Martinduke Shop on Etsy.  

It took about a month for the package to arrive but it was well worth the wait!

All set for a photo expedition!

9-10" tonearms: Denon DA305, Fidelity Research FR24 MkII, FR54, FR64fx and Grace G540L

Tonearms are like violin bows...

When I posted the above picture + caption in my 2020 preview, I was drawing an analogy in which the turntable is a violin, the tonearm is the violin bow, and the phono cartridge is the violinist. Due to unforeseen circumstances that year, I was only able to cover 11-12" transcription length tonearms contained within the Garrard 401 + Alfred Bokrand AB309 essay. Even if I'm committed to transcription length tonearms for ultimate LP reproduction, below are capsule reviews of 9-10" tonearms I also like and use. 

Denon DA305

Spindle > pivot = 230mm

Although not the last word in terms of detail retrieval, the DA305 has the ability to recreate the atmosphere of a fine concert hall. Aside from bringing out the best from the Denon DL103, it also partners well with low compliance magnetic cartridges like the Shure M3D. Musically, very honest!

Fidelity Research FR24 MkII
Spindle > pivot = 230mm

The FR24 displayed excellent synergy with medium to high compliance magnetic cartridges. It was the perfect mate to the Nagaoka MP10 and is equally at home with the high compliance Shure SC39ED. The sound was not as exciting when paired with lower compliance cartridges. A beautiful design with a bejewelled feel!

Fidelity Research FR54
Spindle > pivot = 230mm

Tonally, the FR54 sits in between the DA305 above and the FR64fx below. I love this tonearm because it sounds detailed yet musical - a combination of virtues that's not easy to achieve. It is best paired with low to medium compliance magnetic and moving coil cartridges. Although at the limit of its range, it can handle an Ortofon SPU and does quite a fine job on playback! 

Fidelity Research FR64fx
Spindle > pivot = 230mm

This is the most massive tonearm in this group and the only dynamic balance design. Top flight low compliance moving coils like the SPU are its natural partners - definitely not designed for high compliance cartridges. It allows the proper cartridge to trace every micron of detail from the LP groove. However, there are moments when this virtue gets in the way of musicality, since it can also sound analytical and dry. It's the antithesis of the Denon DA305. Could this be the reason why its FR64S sibling is more sought after? 

Grace G540L
Spindle > pivot = 222mm

In the mid 90s, the G540L proved to my ears that the concept of a removable headshell being detrimental to good sound was a myth. So I unloaded my Rega RB250, RB300 and Sumiko FT-3 and started collecting tonearms that accepted IEC headshells.😊

Happy listening! 🎵

Old Flame - Rogers LS3/5A

As I mentioned in my reply to a reader's query in Snell Type J III, Part 1, I'm the temporary caretaker of a pair of 15 ohm Rogers LS3/5As while my buddy Jose's basement is getting sorted. 

ca. '93

Long time readers know that I was a BBC LS3/5A user. A pair of 15 ohm Rogers replaced my Magnepan SMGas in '86. As a partner in a company that distributed Spendor speakers in the Philippines in the early 90s, I also owned a pair of 11 ohm bi-wireable Spendors. 

ca. '94

In the preceding two pictures, my pair of DIY PP2A3 monoblocks struggled to drive the Spendors in my tiny apartment. Despite that, the BBC near field monitor opened my ears to the virtues of directly heated triodes. Alas, they were superseded by Altec 755s because I needed more efficient speakers to pursue flea-powered single ended directly heated triode (SE DHT) amps.

The Bextrene cone KEF B110  5" woofer + the complex crossover/EQ network = 82 dB/1W/1M, very inefficient! But kudos to BBC engineers, IME, the speaker is still a relatively easy load for low-powered tube amplifiers because of its high(ish) impedance across the audio band. 

Just as I remembered, the LS3/5As are very capable of portraying the midrange magic of an SE300B or even an SE2A3 at near field distances. However, to get some boogie factor out of them, they need the power output of at least a Dyna ST35. But as good as the ST35 amp is, a catch-22 situation ensues because it sounds veiled compared to the aforementioned SE DHT amps.

Snell Type J III + Rogers LS3/5A

I was viewing the past through rose-tinted glasses when I posted (#3) in HiFi Haven - mea culpa! There's a greater similarity in tonal character between the Rogers LS3/5A and Snell Type J III. The Altec sound is another entity altogether!

Given my post SE amp/High Efficiency transducer expectations, the Altec 755As in Dr. Bae/Silbatone cabinets are tonally more lifelike across the audio band, offers better resolution, has more low frequency extension, greater micro and macro dynamics and plays at higher SPLs in a package that's not significantly larger. 

Listening to the LS3/5As was like seeing a former flame. The familiarity is there but the chemistry and fireworks are gone. (◞‸◟)ﾉ

Thorens TD124 Tips

 

Cheap and EZ

Neat P58H/Shield MO19

This experiment was inspired by the spring-mounted motor on my Neat P58H.

Realistic MKVIII

Even if the rubber grommets on the MKVIII are still supple and intact, I replaced them with 302 stainless steel compression (1/2" x 0.600") conical springs, Grainger part no. 1NDB4 and heard a significant reduction in noise.

Left = Neat P58H original
Right = 1NDB4

Heck if it works with the Japanese idlers, it should also work with the TD124. So I ordered smaller conical springs from zorotools on eBay for the TD124 and TD124II.

1NCY2 = 5/16" H x 0.48"

Be careful removing/installing the circlips. They can fly across the room, along with expletives.😁

1NCW4 = 1/2" H x 0.48"  

Some may argue that the "springy" motor mount can introduce pitch instability and also, as originally designed, the belt provided ample isolation from motor vibration. The springs are cheap, so let your ears decide.😉

Magnetic vs. Non-magnetic Platter

 TD124 standard platter = heavy "magnetic" iron

I used to believe there was negligible sonic difference between the heavy iron platter from the MKI vs. the MKII's non-magnetic platter.

Lighter non-magnetic platter
issued with the TD124II 

However, in the intervening years, I've come to realize that the heavy iron platter bestows gravitas to the TD124 design! 

TD124II + heavy iron platter

When I found an older iron platter at a reasonable price, I grabbed it and installed it to my Mark II!

IMHO/IME, as long as one keeps the original aluminum outer subplatter + clutch mechanism intact, the magnetic platter + phono cartridge interface isn't a problem. Ortofon and Thorens were aware of this back in the day and their recommended procedure of setting the VTF as pictured above is still relevant now. I've been using the SPU, DL103 + other phono cartridges on the iron platter for over two decades with no issues.

Let's not go to the light (or no plinth) vs. heavy plinth.😄

Reference

 For maintenance and restoration information, visit The Analog Dept. Thorens TD124 webpage! 👍👏

morrison micro 2A3, reimagined + Kasuga Wireless KA6625ST output transformer

Joe Roberts' piece, "I Never Met a 2A3 Amp That I Didn't Like," from Sound Practices Issue 15, is very persuasive. I built jc morrison’s micro 2A3 amp soon after I received the issue via snail mail fresh from the printers in the mid '90s. After rereading the article in ‘07, I got inspired to make a Radiotron SE2A3 variant.