General arm Data
12 inch tonearm:
Null points at 66, 120,9mm, according to Baerwald.
Mounting distance 304,75mm
Preparing the plinth or arm base
In most cases the plinth will be made out of wood. For any other material the procedure is similar. Differences might occur in the choice of the right tool, slate for example cannot be drilled with the suggested wood drill of course.
First, the centre point of the tonearm, needs to be determined. This is where the hole for the arm will be drilled. Instead of the paper showing the correct mounting distance (12 inch or 30,48cm) I recommend to use a piece of wood, with a hole for the platter and a small hole for a drill as marking tool. It is useful to draw a circular line to find possible locations for the arm. Check the placement of the arm for enough clearance to all sides and good looks.
Make sure the drill used as a marker is exactly vertical. It is easy to verify with a ruler.
For illustration purposes I have drawn a line with a felt pen to show possible placements of the arm along this curve. Don't draw lines on the plinth that you cannot remove.
Put the arm on several locations, along the curve to find the desired position. Take care of clearance and the looks, hence proportions of where to place the arm.
If the decision for the final placement of the arm is made, it is time to drill the hole.
I recommend a Forstner drill with 20 or 22mm diameter. This way the hole will be larger than the pillar of the arm, which has 19mm diameter. This allows to fine tune the position and makes sure the arm vertical tube is not touching the plinth in any other place than the mounting base.
The drill needs to be as vertically placed as possible. I strongly recommend to unmount the record deck and go to the workshop with the plinth alone. This picture is just for illustration, the drill is not vertical...
Mounting the tonearm base
Once the hole is drilled it is a good idea to place the arm into the hole and see if it has clearance in the plinth.
For the test placements of the arm, it is a good idea to hold the arm like this:
This way it is possible to slide the arm up and down, yet have the arm tube under control.
Before marking the holes make sure the distance is correct. It can be measured with the paper tool or a ruler or the custom made wood piece. It is also important to ensure that the locking nut is looking backwards or tho the outer side if you like. This way it is easier to adjust the VTA later.
Once the screwholes are marked us a small drill to make index holes.
When thightening the screws use both hands to avoid 'stabbing' of the base if the screwdriver slips away.
The screws need to be tightened evenly, otherwise the arm base would not be sitting exact.
Try to slip the arm up and down to ensure the arm is not touching the plinth.
This gives a nice view of adjusting the VTA, too. Here you see why placing the screw backwards is a good idea in order to adjust VTA.
Now it is time to hook up the headshell. I was asked several times about the missing finger lift. The regular headshell does have a finger lift, in this case I have removed it, in order to fit the exceptionallly wide cartridge body and for better optics, I admit.
With a spare record try to estimate the correct VTA. Please don't put the needle on the record without a counteweight! See the last picture in the paragraph above for the height, VTA, adustment. Please use the same type of holding the arm.
I use a protractor based on Baerwald/Lofgren curves. The long line shows to the center of the arm, when adjusting the cartridge paralel in point 1 the overhang and the alignment is correct.
The second point is to control and fine adjust the placement. Because the points are on a straight line the protractor has to be turned to rest the needle on point two.
Note, that I made the rough adjustment with the plastic cartridge protector. For fine adjusting I wait until I have adjusted the correct tracking force, then I adjust the geometry again with the bare needle.
When adjusting the tracking force it is again important to stabilize the arm. Stabilize= put the thumb on the arm tube. Please.
The locking screw can look to either side, I recommend it to look slightly down. This way it is pretty much hidden, yet easy accessible. The tracking force is adjusted by pushing the wieght back and forth.
To check the tracking force an external scale is necessary.
The VTA and tracking force procedure might be repeated for optimal results.
Now it is ready to play.