Tag: motor

Premier 751 Vibraphone (part 2) (Job No: 1279)

This Premier 751 Vibraphone is one of those instruments that seemed to have everything wrong with it; the frame was out of shape, major elements like the damper system were broken, and the motor was hanging off.  In 1279: Premier 751 vibe (pt 1) I discussed the structural work that I have done, starting from the ground up, and ending with the commencement of a new damper system.

wpid-wp-1444977859672.jpg

Most of the work in making a new damper system is in the set up, by which I mean how this intrinsically simple system is fitted to the instrument. This is discussed in greater detail in 1260: Premier 701 vibe (pt 2) and it can be seen that I take great care in ensuring that everything is set parallel so that when the damper is used, it rotates freely around its fulcrum points. In reality, because I do not compromise on the quality of materials, the felt I use is of exceptional quality and soft enough to compress around any localised discrepancies. Therefore ironically I have more leeway in the set up of the damper bar, but I cannot guarantee that the same felt will be used from now on, and if a job is worth doing, do it properly. Of primary importance is how the bar makes contact with the underside of the note bars, this is it’s function after all; it needs to be simultaneous across the entire range (left to right or up and down the vibe) as well as between the naturals and accidentals (front to back). So as well as getting everything mechanically efficient, it is this element that I want to get right. I have only ever seen an adjustable system on an Adams vibraphone, and it struck me as a very good idea, especially considering their history of inaccuracy when mass producing components; needless to say despite their system being adjustable, no one had set it up properly before I finally got hold of it, but that is a question of mass produced instruments being assembled by minimum wage factory workers.

The final part of the damper system is joining it to the pedal. In the photograph above I have dropped plumb lines down so that I can mark where, along the damper bar, I want the connections placed. This is an example as to why, when I built the workshop, I put a raised floor in. Besides the added comfort of standing all day on a wooden floor, as opposed to the great discomfort (and harm) from standing on concrete, installing a floor meant that I could get the whole area perfectly flat using a laser level. With a horizontal surface to work off, I know that every time I drop a plumb line down off an instrument, it will be perpendicular to the floor. In practice this means that the two rods that pull the damper are now both pulling at the same rate in the same direction – this is so difficult to achieve that most manufacturers opted to have one pull rod and a central pedal.

I suppose the big question is why do I bother? There are several perspectives to the answer. A vibraphone player generally has an indirect contact with the instrument, they use mallets or bows to generate the sound. To control the sustain and decay on (and in) the whole they rely on a mechanical system. It is my task to give them the very best tools to do their job, so I want the damper system to be expressive as possible and I want consistency across every note. When I say this is my job, it seems blindingly obvious why I go to great lengths to get things perfect. The counter is also true: if a vibraphone does not have this done by a maker or repairer, then they are not doing their job. Furthermore, it is in my nature to be extremely particular and exacting, which why I became an instrument maker, but despite the lack of financial reward the main rewards are in job satisfaction. Over time, to achieve the same level of job satisfaction and therefore reward, I have to aim higher and higher and only my very best work gives that satisfaction. Consequently I always do my best, still living to the Scout promise after all these years!

wpid-wp-1444982558012.jpg

Whilst I was working on this vibe, I use the opportunity to try out my moulding system for replacing the note pegs. There are more details on this kit in 1264: Premier Vibe Note Pegs. There was also a new motor system fitted (1101: Premier vibe motor conversion) and some new alternative spare parts that I have made. In the photograph below the motor speed control can be seen tucked away inside the top transom, and two new note cord hoop mouldings. The Two cord hoop mouldings I have made in bronze as opposed to plastic, so I will be very surprised if they ever break again. They are a little bit more expensive than the originals were, but the originals are obsolete and I have run out, but my replacements are far superior, but it is the unit cost which has prevented me from replacing all of them.

wpid-wp-1444982950273.jpg

wpid-wp-1444983593240.jpg

Premier 751 Vibraphone (part 1) (Job No: 1279)

wpid-wp-1439540643965.jpg

Here is a Premier 751 Vibraphone in a bit of a state, sent in to me to be made usable.  Whenever I get an instrument like any of the Premier 7 series vibes, I always ask how the instrument used.  This is because I have invariably seen the same model instrument many times before and have a good knowledge how they break.  For example, the resonators on the 751 (or 701) vibraphone are fixed in two points at the low end, but at the high end there is no mechanical fixing, they simply rest on a transom.  Using gravity is fine on most instruments for holding resonators in place because of their mass, but to then expect gravity to be a structural component of an instrument’s design and resist the much larger forces of motion and mechanics is simply ridiculous.  And yet I see it used all the time, by every manufacturer and even overlooked in most renovations, which is how I have come to the conclusion that either nobody knows what they are doing, or that they are making things to fail to generate future income.

So to get back to this vibraphone, what has resulted is that when viewed from above, the frame has become rhomboid and when viewed from the front it has become trapezoid.  If this frame distortion is ignored, the instrument will eventually just die, but with a simple sub frame the problems can be rectified.  The frames I make have a life time guarantee, that’s my lifetime, not the life time of a product (which is up to the moment it breaks), so essentially they are extremely strong, strong enough to be used to pull a frame back into alignment as opposed to just retaining it in a distorted shape.  Alignment of an instrument is very important for longevity, especially when there are moving components like on a vibraphone.

wpid-wp-1439540573975.jpg

Everyone has a method of working, I start at both ends; from the ground up and the top down.  What I am doing is working from the known points and verifying that those datum lines are correct.  By the ground up I mean the contact with the floor, and the top down is the players interaction.  In order to get fit a subframe to Premier vibes it is necessary to remove the two lower transoms, this makes it easier to also fit new casters.

Another constantly recurring problem with most percussion instruments is the material used to make the frame out of.  Aluminium is used because it is “light weight”, but it only saves weight if the component is designed properly to overcome its low strength, mostly manufacturers just use more of it to add strength which is expensive and heavier than steel.  Premier have deviated from the norm and actually used an extrusion; all the little grooves massively increasing the components bending resistance.  Where the casters are bolted on, Premier have even used the plastic end cap as an internal support to the tube to resist the tube crushing and wear on bolt holes.  In fact on most of the Premier vibraphones I see, it is the steel note rails and not the aluminium that is visibly bent.

However, the problem I encounter when modifying an aluminium frame is holding the fixings in place.  To simply drill a hole and put a steel bolt through is never going to last; the aluminium extrusion will compress introducing a gap, therefore movement, and therefore wear on the holes thus rendering the whole exercise a complete waste of time, effort and the customers money.  This means that I have to make a whole range of subsidiary components to support the bolts which will affix the proposed frame modification, which takes careful thought, time and always some compromises to keep the ultimate cost down.

wpid-wp-1439966437451.jpg

The final subframe looks very simple, but it is doing many jobs:  It holds the four casters parallel to the ground, fixes the width of the instrument, pushes the back two casters outwards to remove the frame twist, pulls the frame back square so that the note bed is horizontal, and holds it there during use of the damper pedal, and finally it increases the structural strength of the whole vibraphone so that it can withstand being wheeled around the buildings where it lives and is played.  Like all my solutions, I use the minimum number of wing nuts to reduce the players time when setting up or packing down; three nuts and the legs can be folded away.  The only downside is that one has another component to carry, but only because I retained the original pedal bar to save money.

wpid-wp-1439967306938.jpg

With the frame problems now rectified I turn my attention to the next area, and look at the damper bar.  It is immediately apparent that there is a problem – one of the leaf springs has broken.  They always break, the constant bending work hardens the steel making it increasingly brittle until it snaps.  The thread in the plastic ball is stripped, and the ball is cracked.  The felt is more like carpet than felt, and the bar itself is bent.  Each of these problems can be repaired, but then you would still be left with an ineffectual damper system which has components that are prone to failure, and that is not what my customers want back as a completely refurbished instrument.  Additionally my aim is always to return instruments that will give years if not decades of use.

Having made a new damper system recently on another vibraphone (1260: 701 vibe damper (pt 2)), it was a good opportunity to repeat the process.  I am constantly reviewing how I do things and looking for improvements, or developing methods to make the process quicker and cheaper without compromising quality.  This was no exception, I tweaked a few aspects of the design and the construction but essentially it is the same as before.  By increasing the width of the bar I have increased the surface area of the note in contact with the felt which results in much better damping.  On an operational level, because the bar is hinged, and because I have designed it, there is minimal horizontal travel as the bar travels through its arc.  The original design, because of the leaf springs, shifts left to right as the bar is pulled down and up; this lateral movement not only drags the notes around, but from a musical perspective it creates woolliness in the damping.

The original Premier damper system, is an ugly, inelligent and inefficient design solution that I would never have been happy with, but that is essentially my gripe with most instruments and all of the brand manufactures; they put into production badly designed products which are then made cheaply and badly, and endorsed by high profile musicians.  Even worse, a high profile musician “designs” and markets a new instrument.  Whilst musicians know when they are playing on a nice instrument, they generally have very little idea as to what makes the instrument good besides the obvious.  I have spent decades learning about materials, mechanical engineering, acoustics, etc, and I have more questions than ever.  It’s like the drummer that wants to be a front man – the musician that wants to make instruments.  Why don’t they start with something easier to understand and simpler to make like a violin or a guitar for their private enjoyment?

This repair continues in 1279: Premier 751 (pt 2)

Premier Vibe Motor Conversion (Job No: 1101)

wpid-img_20140619_125711.jpg

This is a replacement motor unit made for a Premier 751 vibraphone.  The on/off switch, and potentiometer are on fly leads so that they can be fit either side of the leg hinge, on the underside of the high end transom.  The grey box contains the speed control PCB, capacitor, and various connectors, with an IEC socket fitted so that the power cable can be removed.

The motor carriage is made to fit 750 & 751 vibes, but will probably fit older models.  Like everything I make, it has been designed to overcome problems that I have had to repair many times.  This carriage is not only strong enough to actually hold the motor, but will actually stiffen the note rails and their joining piece.

Locating the pot and on/off switch to the end frame avoids the normal difficulties experienced when bowing the notes, and the leg hinge will offer protection to the components during transportation.

The grey box is the brains.  The IEC socket was a moment of realisation during conversation with the customer.  By using a standardised socket as opposed to permanently wired, prevents straining or damaging the cable which occurs when winding it around the instrument, and makes replacement simple.  In fact finding a replacement cable on a gig is now simplicity; just borrow the cable one powering the kettle, or pc, or guitar amp, etc, etc.  Additionally, there is now no need for anyone other than myself to open that grey box!  Finally, there are two small holes on the side, the small one is the power led on the PCB, the larger one is access for the trimming pot which can be used to increase the maximum speed, so can be ignored.

To fit it, six holes need to be drilled, four for the motor carriage and one each for the pot and power switch. Then its just a matter of routing the cable.

Vibraphone Motor (Job No: 892)

Annoyingly the motor and speed control unit I had in stock just didn’t work. I had to design a removable motor unit for a vibe, and the motor assembly was at its core. To make matters worse the speed controller has been dropped by the manufacturer, so I now have an entirely new system to fit into an existing design. The final added layer of complexity is that I have to modify the new controller in order to achieve the same usability.

Having been shopping, I now have everything I need:
20130703-094949-AM.jpg