Retro Cool Tonearms
Rek-O-Kut LP743 - ROK S160 tonearm in front and Velvet Touch [Gray Research clone] viscous damped unipivot tonearm at the back
Gray 108 owned by my friend Ding in NYC
Gray Research is an American audio manufacturer from the golden age of hi-fi that produced equipment aimed at both the professional and home audio enthusiast. Their most innovative product is the viscous damped model 108 [14 5/8" overall length] transcription tonearm which is the father of all unipivots and probably the most stable of all designs since it is supported by a ball and socket that floats on thick silicon oil. A lot of these found their way into the consoles of many radio stations DJs during the monaural era and need to be rewired for stereo application.
Technical drawing of the Gray viscous damping principle - note the thin film of silicone oil (damping fluid) where the ball floats above the cup (socket).
My monaural playback front end - ROK B12H, Velvet Touch and GE VR triple play mono cartridge
The Velvet Touch tonearm is a Japanese 9" [~300mm overall length] OEM clone of the 108 that sold for about half the price implementing the same engineering principle if not an outright copy. VTA is adjustable within 3/4"- 7/8" on my sample but no anti-skate or cueing facility and overhang is fixed. I have found this branded as Calrad SV12 or Realistic A-3 and speculate the OEM may have been either Neat or Grace. Sakuma uses the transcription length Grace version in his system. Based on the measurements I took from a Realistic MK VII turntable the spindle to pivot mounting distance is 222mm for the shorter model which is shared with most 9" Grace tonearm models.
This tonearm was originally wired for mono and can be rewired for stereo compatibibility.
When considering the purchase of a Gray tonearm or clone it is very important that it has the cartridge slide  since these are practically unobtainable. Originally the tonearms were sold with a set of cartridge weights  to balance and apply the proper tracking force for cartridges from that era. This is not too crucial since coins with dabs of blutack can be used as substitutes [see below]. The jewelled needle bearing is mounted at the center of the pivot socket  and then the cup is filled with about a 2-3mm film of 600,000 centistoke silicon oil where the ball  should float. I have no information on the original silicone viscosity or the amount used. In my experiments I found the silicon oil I found in RC hobby shops were all too thin and thanks to a kind Vinyl Asylum inmate who sent me samples of the thicker variety which are also available from Turntable Basics. I started with 300,000 cSt silicone oil - the grade used in cueing devices - but now believe that 600,000 cSt is close to the standard viscosity originally used since I achieved the 2 second delay after dropping the tonearm 2"-3" above the record with the pivot dome screw [top screw and lock nut - 5 below] properly adjusted.
See the ~ 2 second delay drop on YouTube
The pivot screw  is domed at the bottom which rests on a jewelled needle and should be adjusted [along with the lock nut] for .5mm-1mm clearance according to Sakuma. Adjustment will be purely trial and error. If the gap is too wide the tonearm will not drop or swings out just like when excessive anti-skate force is applied on a regular tonearm; when over tightened there will be no delay in the drop, effectively disabling the viscous damping system. Proper clearance is achieved when the tonearm falls from 1" above the LP with a 2 second delay.
This arm is massive by contemporary standards which limits cartridge choice to lower compliance cartridges. It is ideal for mono applications. See below for compatible cartridge recommendations.
If there is too much VTF, additional weight can be added behind the pivot [counterweight area].
A penny [2.5-3 grams] blutacked anywhere in front of the pivot can be used to obtain additional tracking force. Just remember that as the weight is moved closer to the stylus VTF is increased. I use a pocket digital scale to measure tracking force [and additional weights] mounted at record playing height beside the platter.
Another Japanese Gray clone the Argonne AR600. It is slightly longer than the Velvet Touch, the spindle to pivot mounting distance = 9 3/16", no VTA adjustment at the pillar but arm height can be altered slightly through the three arm base mounting screws. The whole tonearm is cast alloy instead of folded metal in the Velvet Touch.
Gray tonearms in a 50s-60s radio station DJ booth
The later model 212/216 looked leaner, has an articulated head (vertical pivot near the headshell mount) like a Dynavector DV505 and did away with the silicone damped ball and cup. Pivot to spindle mounting distance = 8 5/16" for the 9" [9" pivot to stylus aka effective or 12" overall length] or 10 37/64 for the 12" [12"effective or 16" overall].
These tonearms employ gimbal bearings and are also massive by contemporary standards. The S120/S160 are earlier stereo versions wherein tracking force is applied through the counterweight and the Micropoise S220/260 is a later development and can be considered as the forefather of dynamic balance designs - the counterweight is used to balance the tonearm and tracking force is applied by the disc on top of the pivot, it also has a primitive anti-skate feature which may not be of much use if VTF is over 2.2grams. Watch out for mono versions of the early static balance type since conversion to stereo may pose a problem due to the headshell [2 contact pins vs. 4] interface. I have no specs on effective mass but these are more massive than the SME 3012/3009 and various vintage Ortofon tonearm models.
Adjust the bearings for minimum play and friction.
Micropoise manual at Vinyl Engine.
Bogen (Lenco) L70 arm
Early Bogen/Lenco turntables with heavy platters were fitted with this tonearm. Known in continental Europe as the Lenco L70 and in the USA as the Bogen B60, 61 and 62 models. It is fairly massive and used high quality bearings that can support the DL103, DL102 mono as well as vintage Shure, Stanton and Pickering. There is no counterweight instead it uses springs to apply tracking force. Spindle to pivot mounting distance = 230mm, it is practically a 10" arm. Click here for comprehensive technical and servicing information provided by Colin's Strictly Idler website. More information can also be found at the Lenco Lovers Forum.
Click on picture to open vintage BBC link
This is a true transcription quality arm that was sold separately in Europe and was used by the BBC mounted on a Thorens TD124. A handful of Lenco enthusiasts are already aware of its musical potential fitted with lower compliance cartridges sporting conical styli. I have seen vintage pictures of this arm partnered with Thorens TD124 or Garrard 301 in professional European installations.
If you decide to fit a modern tonearm on your L70 or B60 series, send it to me I will pay shipping!
Cartridges I use for for experimenting with vintage high mass tonearms
L - R: Shure SC35C, Shure M7D, M3D and Grado GTE+1 with DJ100 stylus (medium compliance)
The Shure M3D was the first stereo cartridge offered by Shure in the late 50s followed by the cheaper M7D. They were offered either with a low compliance spherical .7 mil stylus assembly [N3D] that will track between 3-6 grams or a medium compliance [N21D] tracking at 2.5 grams MAX! The only difference I hear between the two models is slightly better stereo separation with the M3D. To my ears these classics are the MM equivalent of the SPU. Original and replacement stylus assemblies are still widely available with the original giving wider frequency response, slightly better tracking and more refinement. The M3D/7D lineage survives in the Shure SC35C very popular in DJ applications. It does not posses the midrange warmth of its older brothers but I would highly recommend it to people who want to try out a high mass tonearm since they can be found for about $30 if you shop wisely. The spherical stylus tracks between 3-5 grams.
L - R: Denon DL102, Stanton 500.V3, Classic Stanton 500 mkII (discontinued) and GE RPX
High mass tone arms partnered with the proper cartridge are great for monaural playback. Before discovering the mono triple play GE variable reluctance I used a Stanton 500 body with a 78 rpm stylus. It blossoms with the stereo LP .7 stylus fitted to a massive arm. The 500 MKII has been discontinued but the $30 500.V3 version is virtually the same cartridge also highly recommended!
I have yet to hear LP damage or groove wear caused by using the DL103 [2.5 grams] and the SPU [4 grams] for almost 10 years. Besides if high VTF significantly wear out the grooves, we will not be enjoying LPs from the 50s and 60s. A misaligned elliptical stylus tracking at 1.5 grams can cause more damage in my opinion. For years elliptical and various other complex stylus profiles have been touted to retrieve more information from the groove. Looks good on paper and charts but I'll take a musical sounding spherical stylus equipped cartridge any time over something that is just retrieving more gunk.
To hear the fullest potential of these tonearms they need to be used with cartridges which have low compliance. There is no provision for overhang adjustment which is not too much of a problem with a spherical stylus as long as proper spindle to pivot distance is observed in mounting. I listed my favorite MM cartridges above that work well with these tonearms but have also tried the Denon DL103 to both ROK and Velvet Touch tonearms to compare with the SME 3012/DL103 combo. Both held their own with similar amount of detail retrieved just presented differently.
The general consensus amongst high-end aficionados is that the tonal balance of vintage tonearms and cartridges tend to highlight the midrange and compress dynamics. Maybe that is true within the context of a modern audiophile system but in my SET/High-Efficiency system this is a lot less magnified. If you are in pursuit of musical satisfaction it is time to develop an open mind in order to investigate other ways of achieving that goal.
In the USA a lot of people are still skeptical of the musical abilities of these antiques and the few who recognize their virtues maintain their silence. On eBay, the top bidders for Gray and ROK tonearms as well as vintage Shure M3D/M7D cartridges have been Asians and Europeans. For years they have known the virtues of WE/Altec, EMT, TD124, Garrard 301/401, SME 3012/3009, classic Ortofon, Denon DL103 and other vintage classics which are only catching the attention of mainstream audio hobbyists in the USA recently.
Listening to playback devices made more than half a century ago made me realize that technology has not advanced significantly and most claimed improvements through the years have been mostly sideways.
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