For over a century now, having cut the music onto the record groove, we have been attempting to retrieve this stored information using a pickup cartridge…carried across the record by an “arm”.
More often than not, unsuccessful, there have been some truly “inventive” solutions!
Here’s our question: Have any of them have even got close to understanding what is actually needed and in so doing, to perfectly undo what was done?
Namely, to re-create: The Record Cutter…But in Reverse.
It sounds not all that difficult when all you do is think about it.
It is not quite so easy when you try to do it:
We are talking measuring distances smaller than the wavelength of light…Look at the reflection of any object against a piece of glass. We are talking information smaller than that!
In fact we are actually down to a single molecule of vinyl variation!…Moreover, we want the stylus to do it accurately, without adding any extra distortions.
It is not a lot to ask, is it!
We might never achieve it (and in itself that is the pure joy of analogue) but in creating AK 1, that was the challenge we set ourselves.
Merely by defining the problem and we realised that not two but Three Criteria had to be satisfied:
– There could be No Resonances – resonances cause movements of the cartridge – Unacceptable.
– There could be No Tracking error. Records were cut without this, why should we now introduce it?
Satisfy those two pre-conditions and initially it seemed that was all that was required.
Certainly, at best, that is where today’s state of the art has stopped.
It was during development, however, under exhaustive measurements and with listening tests against Master Tapes we knew something was still wrong:
There was one more unexpected factor that had to be solved:
– There could be No Feedback. More on that later.
Defining the problem was only the beginning.
It then became a design exercise…and then an engineering problem to create the final solution.
At each stage, selection of each and every single component, material and form, everything was questioned and scrutinised, with nothing being taken for granted.
Rigidity – The search for motion
To perfectly support a cartridge across the record an arm needs to be entirely passive; it must not behave as a fishing rod flopping about with a weight at the end. But here’s the problem: We are limited by the sheer amount of material we can use in the arm. This has resulted in horrendous designs that do flop about and ring like a bell; peaks of 20-30dB are commonplace even in expensive, “reference” arms! These peaks are all too easily heard. They mask information and must be avoided at all costs. Rigidity is paramount. Damping? That does not work: it loses and smears musical information. So, we have two requirements in conflict and that was the challenge.
Many years ago began Funk’s development program of an advanced technology called F.X. From that we released FX3. Against the norm of 20-30dB peaks, FX3’s main resonance was a meagre 6dB; this made it not only a class leader but also a giant killer. Immediately Funk has become pre-eminent in the field of arm rigidity.
Now, with AK 1, our goal has been the total elimination of even that 6dB peak.
AK 1’s new arm beam is the next generation ultra-rigid F.X. It comprises a laser Sintered Ceramic Cross Beam formed within a Ceramic shell. Delivering phenomenal low-frequency rigidity, it is now below audibility. Simply the cartridge does not know an arm is supporting it. It is a tremendous achievement and with it we have satisfied our first criteria: No resonances.
Tangential arms claim to have lower distortion…But do they?
In developing the “ultimate” arm, each and every distortion needs to be eliminated. Records are cut in a straight line. Radial arms carry the cartridge in an arc. This gives rise to small amounts of error. To remove this error, a tangential arm seems to be the way to go, or so one might think…
It can be shown that as compared to a radial arm, because of the way it operates, the tangential arm principle not only has higher distortion per se but higher distortion overall across the entire record!
By definition in a tangential arm, the groove-force pushing against the stylus is lateral – It pushes left and right. In other words to operate, the cantilever MUST first be pushed out of alignment and then drag the rear pivot assembly across with it.
But the cantilever is only a few millimetres in length.
When this goes out of alignment it immediately generates a higher level of tracking error than a radial arm! (Never mind that the coils are now also out of alignment!)
It gets worse.
Obviously the rear section of the arm, which simply by its existence has high mass compared to the tube and unlike a radial arm that is anchored at the rear, this part has to follow and the inertia of this component is high. It forces the cantilever, constantly, out of alignment, all the way across the whole record.
“But, air bearings have no friction. Surely that helps?”
Lack of friction of air bearings might sound a great idea but actually that also makes matters worse:
Look again at the inertia of the rear of the arm – Once in motion, What is there to stop it? If the answer is: “Nothing”, then it will overshoot!
(One only has to see an air-bearing hockey puck game: The puck has very low mass yet it flies freely all around the table. In other words air bearings have no damping.)
The only force controlling the arm is the reaction from stylus and the groove wall. First right and then left. The whole system wiggles across the record. It is NOT a smooth motion and is not good.
Now to pivoted arms: An analysis of the vectors of the forces acting on a conventional radial arm shows it does NOT experience this in the first place. This provides a good, stable starting point.
In AK 1, we have taken this to the limit. Unconventionally the headshell rotates: Governed by the arm’s position on the record, it keeps tracking error both constant and at Zero.
The beauty is that this “Zero” is mathematically defined.
To achieve all this? AK 1’s solution avoids multiple beams. (These would all require multiple pivots, each adding both friction as well as resonant components.)
AK 1 uses just one pair of Laboratory grade, ultra miniature bearings.
Limiting the number of races ensures minimal friction levels, whilst removing extra arm beams means there are no extraneous resonances to deal with.
Delivery of zero tracking is now achieved by anchoring the head to the rear of the arm. The head is precisely guided to follow a mathematically calculated trajectory via a “thread”.
Well, at least that one is easy; pop down to a store and a fishing line will sort that problem out?
Not at all. The requirements for the thread itself are just as precise. Temperature effects on the long relative distance from rear to front of the arm risks the thread shrinking and increasing tension, thereby loading the bearings, thereby increasing friction. Even advanced polymers were rejected.
AK 1 employs a filament of tungsten / rhenium. This material combines very high tensile strength with very low coefficient of expansion – low stretch. As it will not stretch, a low tension can be used and this means: the bearings are not loaded and we don’t have two twangy guitar strings!
(Rhenium? It’s one of the rarest elements on earth).
Criteria Number 2: Zero Tracking error. Satisfied.
We had now developed an arm with no resonance and no tracking error. As it stood, this arm was good, in fact very good. AK 1 could already lay claim to the title of a “best arm”.
At this point in time, most companies would have stopped.
To us, however, there was still a “But”.
A Record cutter is:
“A rigid construction; No tracking error & Not affected by the outside world.”
We had not arrived at that Holy Grail: “As perfect reproduction as we could conceive “ or
“The Record Cutter…in Reverse”, for something was still not “right”.
Something was missing, or rather, something was being “added”.
Finally…Feedback…and how to eliminate it:
Our ultra-rigid, zero tracking error arm was still falling prey to and exhibiting unexpected and unwanted colouration.
We could hear “more” than we ought. But these were not from within the design, per se.
This “more” turned out to be from external energies entering the arm, adding to and modulating with the cartridge’s output.
This is where AK 1’s coup de gras comes in.
AK 1 goes that vital one step further: It decouples the cartridge from the outside world via a controlled “bubble of isolation”.
For AK 1 we developed a new novel, complex but quite precisely filtered mounting system.
It is this that finally, accurately and uniquely mimics the action of the cutting stylus.
The cartridge now experiences both freedom of scanning movement together with structural rigidity all the way up to 20kHz.
For a passive device this is not easy and no other design has ever attempted it in this way and it is by elimination of all extraneous possible distortions that the cartridge precisely emulates the motion of the cutting head. It is now free to work and give you the music.
AK 1 is: “The Record Cutter…in Reverse”. It has pat pending for the new technologies it brings to bear to record replay and we offer it as a total solution for you to experience and enjoy.
Each AK 1 is intended to be optimised for any cartridge thereby ensure a critically damped response. Each is meticulously assembled to order to match to any chosen cartridge, a process that alone takes about 6 ½ hours.
– Miniature lab standard, temperature-optimised ball races for minimal friction.
– Low Hysteresis Titanium cabling for zero tracking error across the record
– Mass Optimisation for each cartridge
– Next generation Sintered Ceramic F.X Arm beam construction delivers vanishingly low levels of flexing and soholds the cartridge stationary above the record.
– Decoupled Cartridge Mounting isolates the generator from external influences.
– Radial Arm geometry minimises lateral stylus forces to improve over tangential tracking arms.
– Direct Damping prevents sub-sonic instability.