The fabulous fluids

Granddaddy, the Reference #63
No pitch control (wet or dry) visible, unless it’s the knob on the right hand side of the strobewheel, which M.J. claimed was a clutch. Arm appears to be a 10” with the cylindrical arm lift and 2 sliding and 1 rotating counterweight.

As far as I’ve seen, the arms come as 9”- 229mm, 10”-254mm and 12”-305mm in general, though I’ve come across a couple of variations and heard talk of a 13”-330mm, but never laid eyes on that one. Furthermore we have to keep in mind the Saturn arm is basically a Fluid as well. We’ll get to that later. The two parts of the arm that are normally positioned in the house (helmcap) just deep enough to allow free swing, can be taken out another 7 mm on each side if desired. Lower the cradle on the vertical arm shaft so you can reach the 2 screws underneath the helmcap.
Screws under helmcap position the two ends of the arm.

Dry pitch- No Hydraulic Reference ? And behold : 1 large sliding counterweight, 1 small sliding and 1 rotating. The small sliding one vanishes afterwards probably with the change in design towards the fluid pitch control (the Hydraulic with donut).
Notice the smaller size of the fluid lift, and the way it is tapering inwards compared with the larger and cylindrical type used on the Granddaddy, later to reappear.

The screw on top of the house (helm cap cover) to drive the pivot a little bit deeper in has not been implemented yet. Large sliding counterweight is eccentric, not only for horizontal balance but also for lateral (unipivot), and combined with small rotating weight for fine tuning. And usually with communal ground, i.e. three wires running through.

As the AC cord changes to a grounded one (Michell >74?) grounding issues appear, resulting in separate grounds for both channels and motor and chassis grounding.
In general the construction remains unchanged for a longer period of time, but then all of a sudden the large eccentric sliding counterweight is replaced with a screw turning cylinder positioned underneath the arm stub in the back, on the smaller arms, the 9” on Electronic Michell >77. It looks weird
The center of gravity lies lower, it can still be used eccentric, but the fine tune weight has disappeared and it now really has become the end stub. It seems a bit out of proportion like this, and therefore lacking elegance. We’re trying to find out whether this modification has been instigated by Michell, who were by then exploring and exploiting the Hydraulic design with the Focus as cheaper version of the HR , for which they also created a Fluid based arm.
Another uni-pivot, sliding cylinder has extra side weights for lateral adjustment, the helmcaptop is now screwed on, pivot screw visible on the top. The lift uses a different system and so does the anti-skating as to prevent it from being a downright copy, but the heart of the matter is still visible. What amazed me was seeing this arm on with asking price about 540 euro’s and that was without cart, I’ve never seen a Fluid raise that much, but perhaps Michell produced less of these so they’re very rare. As a matter of fact, Michell developed a lot of different turntables based upon the Hydraulic’s design,(Electronic,Prisma) but used arms made by others, first Shure SME’s, later the Rega’s. Here shown also a Saturn arm. It has all the makings of the regular Fluid, but the helmcap is flatter, Arm is bent in one, instead of two places, and appears to be using just the one large sliding weight. But cradle, lift and anti-skating look just the same.
saturn arm
Other uni-pivot oil dampened contemporaries were Mayfair, Grace and Hadcock, just to name a couple.
Fluid Arm pivot and inner cup in helmcap (house)
Perhaps a Saturn owner can help me out, does the arm also use the viscose liquid in the helmcap ? And if not, could it still be called Fluid due to the Hydraulic lift ? In the Saturn’s manual I found no mention of fluid in the helmcap, perhaps it’s a dry inverse pivot.

A couple of facts and measures on the Fluid Arms.

Overall Length Effective Lenght Distance pivot to spindle Angle error Compliance
9" 12" = 304mm 228mm 8 5/16" = 211mm < 2% 20 - 48
10" 13¼" = 349mm 254mm 9 5/16" = 236mm <1,6% 13-30
12" 16" = 406mm 304mm 12" = 284mm 8-15