- The design idea is based on the experience of using wood in musical instruments.
- Wood is there for damping, stiffness is provided through wood treatment.
- Together they realise what is called “constraint layer damping”.
Video link: introduction
“Hearing is believing.”
You are invited to test this tonearm!
Introduction / 2
- Energy transfer along the SAMBUCO tonearm to the base is essential for a stable sound-image. A strong unipivot bearing with minimal friction, and an eddy current damping.
- The result is a stiff, medium weight tonearm with a vivid sound without bell resonances.
- An honest word: The tonearm pipe looks like wood, because it is wood, not metal or carbon! It will win a song contest, but maybe not a technomaniac beauty contest!
If you like the idea and if you want to test it,
Yours, Sambuco, Vienna, Austria
let us know:
Table of Contents
The Tonearm Pipe
This is the core of the matter!
The SAMBUCO tonearm pipe is turned from a rather soft wood: “Sambucus nigra” or “Elderwood”.
It grows as a natural pipe and has a lot of pores, which widen as the wood dry ages. Wood grows in annual rings, according to the annual seasons their structure is either softer or harder (f.ex. slower growth in winter).
The tonearm pipe and it‘s function is best explained by the damping principle of constraint layers („CLD“). This is the permanent and solid combination of different materials in one functional item. Each layer has different stiffness and damping properties. Wood is a natural CLD concept.
Tonearm pipe / 2
On the SAMBUCO you will notice that at all screws, joints, and contact areas different materials meet. Consider the speed of sound in soft or hard materials.
metal ↔ wood ↔ plastics ↔ metal
The result is tighter contact and better energy transfer without rattling, reflections, or resonances.
Compare musical instruments: wood gives a nice response when you knock on it. Brass gives a rather nervous response.
The result of measurements should show an even response, without discrete peaks. Their combination creates a structure that has no “peaky” resonance.
Tonearm pipe / 3
The “knocking test”:
Very hard materials (f.ex. ceramic) tend to have discrete high frequency resonances („kling“). Soft materials often sound dull („blob“) You want to hear „tuck“! Short and loud. Loud means good energy transmission, short means good damping.
The “fuzziness” of wood , and its numerous treatments enable the SAMBUCO neutrality in supporting your cartridge.
You are not getting this from any homogeneous material.
Tonearm pipe / 4
The SAMBUCO tonearm Mk2:
We have further improved the energy transfer from the cartridge body to the tonearm: A second M4 screw ensures full contact integration of the cartridge, and the interface to the tonearm pipe.
The SAMBUCO design principle:
Have a minimal moving mass (i.e. needle+cantilever+coils), that is opposed by a single inert “anchor mass”.
The hole tonearm and the mounting base form a non reflective energy sink.
Think of “inertia” as a physical concept, and it’s application in a seismograph.
The SAMBUCO Bearing
The tonearm bearing is a unipivot concept.
All energy has to pass through the single bearing point .
A point contact shows minimal friction.
High magnetic pressure (1.5 kg) at the contact point and an eddy current damping effect will keep the bearing contact “silent”. No chatter!
How does the eddy current damper work?
There is no resistance to slow (normal) movements (< 1 Hz) of the tonearm.
But high speed vibration (like tonearm resonances) will create higher eddy currents in the copper bearing base.
The eddy current damper becomes more effective whenever it is needed (i.e. at higher frequencies).
The chart is symbolic to visualize the concept.
The SAMBUCO offers flexibility for ALL alignments!
- The distance of the record spindle to the tonearm bearing point determines the necessary offset angle. „Alignment“
- For different tonearm lengths alignments you have to drill different mounting holes
into your record player‘s tonearm base. This is easy because the SAMBUCO only needs a 6 mm diameter) hole to fix it.
Alignment options
| Alignment type for tonearm effective length | Spindle – Bearing point distance | Offset angle (degree) |
|---|---|---|
| „Loefgren“ 240 mm | 224 mm | 22.8° |
| „Loefgren“ 300 mm | 287 mm | 18.07° |
| „underhang“ the longer, the better. | n.A. => position along a tangent | 0° |
Video link Tonearm Installation
3) Adjust the offset angle. (Remember the „interface“ can be rotated and fixed with the front M4 screw.) The needle is vertically under the M4 screw! Then fix the second M4 screw for good contact.
There is an explanatory videos for the tonearm installation:
Templates
The SAMBUCO comes accompanied by two templates:
The long template helps-
- To drill the tonearm base at the correct distance to the spindle.
Video link Tonearm Installation
- To adjust the correct offset of the cartridge.
The rectangular template will help to balance the tonearm in order to have the cartridge parallel to the record surface („Azimuth“)
Static and dynamic balance of a unipivot
Imagine the SAMBUCO as a tightrope artist.
- The geometry and mass balance of the SAMBUCO tonearm creates similar momentum forces around the bearing point.
- There are no momentum differences at the needle tip of the cartridge.
- The bearing point is almost on the same plane as the record, so the tonearm shall be immune to warp wow effects.
The SAMBUCO counterweight is designed to add inertia in the horizontal plane.
Usually tonearms offer little left-right inertia to oppose torsional diamond work in the groove. The balancing stick is positioned 90 degrees against the cartridge cantilever axis (= the record groove axis). It allows for fine tuning of the horizontal tracking angle (HTA and Azimuth), a critical set up topic for Uni-pivots.
There is a little spirit level above the tonearm bearing.
Anti Skating
Many elements influence the skating force:
- Offset angle and effective tonearm length
- Needle Friction
- Radius of the needle position
Anti skating force has to be strongest in the outer grooves; then it decreases towards the middle grooves; Finally (inner grooves) it needs to increase again.
The SAMBUCO antiskating solution
Video link anti-skating final
Two dimensional and friction-less.
There are two independently adjustable magnets that apply the anti- skating force to the tonearm. The tonearm itself carries a third small magnet that is pulled outwards (outer grooves), and later pushed outwards (inner grooves). All at the bearing level!
By adjusting the distance and the angle of these magnets to each other, you can fine-tune the anti-skating force. Start your effort with a groove-less (blank) record.
Anti skating
Video link anti-skating final
Due to the skating drag towards the record centre, there is always enough needle pressure for the left channel modulation (green line).
The applied anti skating force increases the needle pressure for the right channel modulation (blue line). ^Ref.
Eventually a balanced optimum, and the best sound is reached. I start this exercise with a blank record. Fine tuning has to be done by ear.
There is a video that explains the necessary steps:
Cartridge Selection
We have tested a number of cartridges with different compliances:
- on the softer side: Shure V15/III with JICO SAS stylus, AT95SH (new series).
- on the harder side: DENON 103R, Kiseki Purpleheart (picture).
Excellent results. Why?
Due to the low resonance design of the wooden tonearm pipe, and the good energy transfer there are no reflections back to the cartridge.A “drop of grease” will support the smooth energy transfer.
(The DENON 103 is said to benefit notably: No distortion or exaggeration of sibilants.)
Tonearm Cable
Four gold plated plugs at the cartridge end, and two non magnetic RCA cinch plugs at the RIAA preamp input are connected by a 34 AWG high frequency copper litz. A symmetrical wiring concept. The fifths wire is for shielding and grounding.
We try to minimize soldering points.
By twisting and gluing these wires together we try to make them mechanically and electrically stable. Only a few centimetres are untreated to keep the cable flexible where it leaves the tonearm.
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Good energy transfer along the SAMBUCO tonearm to it’s base is essential for a stable sound-image. A strong, magnetically enforced unipivot bearing with minimal friction, and an eddy current damping supplements it’s sonic performance.
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Installation Instruction in English