First of all it is important that you have quality loudspeakers with
a very good frequency response that goes deep down and extends well
in the upper regions of the audio band. At the same time it should give
a very neat yet open reproduction of the mid frequencies. A bad
loudspeaker system will make you easily compensate for poor bass response,
bad renounces and standing waves in the system and/or in the room. So
your loudspeaker system should be dependable and also well positioned.
When I told a friend that I had built a pick up arm that was working
well, he said to me: "So all these high end tone arms are either not
as good as reviews may say or they are far too expensive for what they
I momentarily use a loudspeaker system that I have built/assembled myself
using among other things an electronic crossover (Luxman 2003 which
works with 8 x 12AU7). This crossover facilitates the adjustment of
level and crossover frequency. My friend added: "And you are compensating
for the weak points of the speaker system and vice versa".
His reaction of course was understandable. But he was not right because
my speaker system works well with various CD players and standard turntables
BEST IN THE WORLD
The existence of the best pick up arm in the world (and all these other
high quality tone arms: Graham, Goldmund, a.o.) does not mean that you
should not enjoy the fun and the seriousness of the learning process
when building a tone arm or a turntable yourself.
I have built various turntables myself, the first one in 1980. I have
done the final mechanical fine-tuning of Denon CD players originally
costing $1500 and that put them very close to the category of Krell,
Levinson, Theta, a/o.
always had the desire to try my luck in tone arms. It never came to
materializing several ideas because I was too busy writing and doing
other important things. Life is all about priorities. But after talking
to a veteran in audio who had spent his life at building his own arms
and cartridges, I decided to try my luck.
This man had built a tone arm of balsa wood with a length of 40 cm (about
17.7 inches). So I started off with a tone arm of balsa wood with an
effective length of 32 cm (12.5 inches) because I did not have more
space for a longer arm at the time. As you know balsa wood is very light
and you do not reach easily the limits of arm mass in relation to the
compliance of the cartridge. So I combined the wood with strips of thin
aluminum to improve the sonic properties of the balsa and to heighten
the effective mass of the arm in order to be able to mount a Denon DL
103 cartridge. That arm performed rather well and provided a fabulous
and lifelike transient response.
Although visitors liked the sound of it, I myself thought that some
coloring was evident. I was more suitable for a lightweight moving magnet
cartridge à la Shure. The
balsa arm has a uni pivot with no play at all. If you pull the arm towards
you in the vertical plane you can feel that there is no play. That is
one explanation for that incredible transient. So a very important goal
when building the second arm was to achieve an excellent transient.
Hobbyists always have parts from ancient times. They keep vintage stuff
because it can be useful some day (mostly never). I had an old Lenco
(Goldring) turntable with tone arm. The platter was meant to serve in
a record cleaning machine which I intended to build myself. The intention
vanished when I bought a real professional Keith Monks machine. Maybe
the Lenco arm could have parts that I could use. I discovered that the
vertical bearing had enormous play and this would kill any transient
drastically. As you know the tiniest amount of play is disastrous.
horizontal bearing was not a perfect construction either. It consisted
of two triangular shaped "knifes" that rested in tiny rubber blocks
on top of the vertical bearing. These rubber blocks had at top side
a v shaped cut in which the two horizontal knifes rested. The knifes
I could use of course. But the rubber v shaped beds were too soft so
I had to construct beds that were firm and not sloppy as the ill Lenco
construction showed (mostly as a result of ill treatment over the years
by the user I guess).
only did I have to make the bed. I also had to find a vertical bearing
that could be used. It
appeared that it was impossible to extract the knives from the original
arm tube and mount these in a new tube. That is why I decided to use
a small part of the existing arm tube and made a construction.
I had a few 'old' tone arms from Thorens turntables (TD 160 and TD 166).
I found that I could use a vertical bearing of one of them if I took
out the existing arm part and if I put it upside down. I mounted it
on an acrylic base plate.
Mounting it upside down means that there must be enough room underneath
the mounting plate (the base plate). My home made turntable has sufficient
space for that part that originally was the top. The other end of this
vertical bearing ends with a shaft with a small diameter. It needed
more mass and also reinforcement. A craftsman turned the needed part:
a cylinder of 30 mm in diameter and 21 mm high and drilled a hole of
5.85 mm in the center. The cylinder is bolted with two screws on the
thin vertical axis.
There are two ways of applying the vertical pressure (downforce) of
a cartridge in an arm. With a statically balanced tone arm the down
force is achieved by means of weight. By precisely sliding the counterweight
towards the pivot the desired amount of down force is attained. This
method has a drawback. Not every record is completely flat. The slightest
warp causes an up and down movement of the cartridge and this movement
can be translated into swinging. If the tone arm is well constructed
measures are taken in order to minimize these effects. For instance:
by making a construction where the counterweight is at the same horizontal
level as the needle tip. The dynamically balanced tone arm does not
suffer from this anomaly because the vertical down force is applied
by means of a spring. The down force does not vary as much as is the
case with a statically balanced arm because the cartridge is held down
by the spring at all times.
on the arm to view a larger image.
So on top of the cylinder I mounted a strip which is bent at two points
(s shape) marked in the drawing of spare parts as "strip for the attachment
of the spring". At the lower end which is close to the arm base there
is a hole so a spring can be attached.
On top of this bent strip I mounted a u profile with v-shaped cut outs
that forms the support for the arm tube. The top of the cylinder has
two holes at the same distance and with the same diameter as the holes
in the aluminum strip and the u profile. The width of this u profile
is 16.4 mm and is a standard size. It can be bought in the iron ware
shop. The horizontal bearing will only function well if the knifes rest
in a this shaped bed which was precisely cut out. The v must have a
wider angle than the angle of the knifes. The bottom of the V has to
be very sharp so that sliding of
the knifes is impossible. The cutting of the V is a difficult affair
and needs special tools and quite some practice before the right V shape
household scissors I cut from aluminum sheet a strip of about 8 centimeters
long and 2 centimeters wide. Halfway I bent the strip around the short
tube far enough behind the knife bearing so it does not interfere with
movement. The strip has to get fully around the tube and should than
have a flat section where 2 holes should be drilled. After that the
strip should be bent again, but now around the arm tube ending in a
flat section again with 2 holes for tiny screws so that the arm tube
as well as the short tube with the knives can be tightened and secured.
Make with a file a flat side on the 8 mm tube
at one end. The cartridge will be mounted on a small piece of Plexiglas.
Plexiglas has a distinct sound that differs from that of aluminum or
carbon (if you have the ears), but unlike aluminum and carbon it has
a far better rigidity and rigidity is one of the most important features
of a good pick up arm, especially of the headshell.
Drill three holes in this small base plate as is seen in the drawing.
This piece of acrylic is to be mounted on the arm tube with one screw
which is located a bit off center (refer to drawing). This screw makes
it possible to adjust the horizontal angle of the cartridge when changing
the effective length of the arm tube and finding out which length (effective
mass) is the best.
The way this mounting plate is connected to the arm tube has an audible
effect. In general it is advised to tighten screws very well in order
not to create a bending mode which results in a noticeable frequency
that will repeat itself throughout the audio band and can be heard in
coloration of the sound, a sloppy bass and ill defined highs.
When much later when the arm is tried out and you had all opportunity
to determine the effective mass of the arm which gives the best sound,
you have to glue the arm tube and Plexiglas mounting plate together
with 2 component polyurethane glue (in some
countries available under the name Bison Nite) or any other quality
glue (but even all purpose household glue probably will do the job). However
do not put the glue in between the Plexiglas and the flat side of the
arm tube, but just on the sides of the tube in order not to obstruct
the flow of energy (sound) from the cartridge into and in the arm tube.
The optimum arm mass will make the bass tight
and will result in an even and extended frequency characteristic and
will bring perspective in the sound image. Too much mass will make the
sound heavy and restrained. If the arm is too light, a distortion free
tracking of heavy passages will be impaired. Remember that the arm/cartridge
resonance must be 8 to 12 Hz. which is well below the audio band which
starts at 20 Hz. The turntable's resonance should be in the vicinity
of 2 to 4 Hz. so it cannot interfere with the cartridge/arm resonance.
OF ARM AND CARTRIDGE
For wiring the cartridge you can use all sorts of wire as long as it
is light and of small diameter. Better use some wire from an old arm
or buy a special wire which is available from certain specialized dealers.
The kind of wire you choose however plays an important role as regards
to sound quality as you know. Especially the longer wire that you use
inside the arm tube. Sound quality of an arm may sometimes be attributed
to the construction and the materials, but in many cases it is also
the wire that puts an arm in a higher category of quality.
The inner arm wire can vary. The 12" arm of the Sony TTS-3000 (a turntable
from 1969) has a very thin wire. Early Thorens arms have very supple
wire as the later Thorens arms have more sturdy wire. Nowadays many
designers use special wire from Cardas (USA), Van Den Hul (Holland),
For the inner arm tube I used silver plated copper wire with a green
Teflon insulation. That kind of wire is quite sturdy and can only be
used in the arm itself and not at the spots were more supple wire is
required: at the beginning of the arm for connecting the cartridge and
the end of it (pivot) where a transition without torsion is necessary.
At that end I soldered 4 very supple and rather long wires from another
(old) tone arm so that the arm can move freely. These wires should be
connected to 2 cinch connectors (female) that you can mount on a support
which is to be bolted on the general base (not on the sub chassis) close
enough to the pivot of the arm. To this support with the cinch connectors
a phono cable of your choice can be connected which leads the signal
to the (pre-)amplifier.
You can use an ordinary phono cable or special van den Hul phono cable
that leads the signal to an external preamp as in my case and from there
you can use a more heavier interconnect of a quality brand. Adjusting
the arm and fine tuning its mechanical capabilities is as exciting as
choosing the interconnect cables that delivers the best harmonics, dynamics
and a wide frequency band. There are numerous vintage records that will
let you hear the best sound of strings, brass and percussion for instance.
OF THE ARM
Although I started of by damping the arm tube with some long snips of
balsa wood which made the music sound controlled, I found that the damping
is very critical and can inhibit the speed of the musical signal especially
when moving coil cartridges are in use. The idea of damping is not bad
altogether but if you use some damping the amount of balsa that you
would apply also could depend on the nature of the cartridge but foremost
on the sonic properties of the aluminum arm tube. I did not try a paddle
in a bath of a damping liquid with a certain viscosity as in the SME
Arm resonances are probably already suppressed to some extend if you
use a more sturdy inner wire. In any case: the wire should not lay too
loose so it can not pick up vibrations and amplify resonances. The way
to go about it is by putting thin strips of balsa in the rear of the
tube (1 or 2 long strips of say 15 cm, but very, very thin). These will
damp the arm tube and the wire over a certain length. The effect of
the balsa is easily discernible by ear (and by measurement, if you are
an expert in that field). Since your loudspeaker system has told you
before what the qualities are in conjunction with a turntable (or several
turntables), the loudspeakers will tell you exactly what the sonic qualities
of this new arm are and how you can optimize them. Too much balsa is
disastrous for any transient response and openness of the sound pattern.
No balsa will tell you immediately if the low frequencies are uncontrolled
and the high frequencies are unclean.