Tag: vibe

B&H vibe tuning (Job No: 1070)

A set of vibe notes in for tuning.

On the graph, the X axis are the notes – this vibe goes from C to F.  The Y axis are the cents above and below the zero line which is at A=440 Hertz.  The fundamental pitch is the blue line which is generally flat (to be expected as the instrument is marked A=439Hz).  However the red line is the 2nd Harmonic, and as can be seen it goes from massively sharp in the lower octaves of the instrument, to massively flat in the higher notes.

To bring the notes into tune both of these lines should read zero.

 

Ross Vibraphone (Job No: 1064)

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This vibe is in to fix a motor problem, however there are more problems; broken note rail, and a dreadful repair that someone has done to the frame which means that the diagonal braces don’t even reach the connection socket

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Plus welding commonly known as “bird shit” which aptly describes its appearance and strength. What is more, whoever did it left sharp bits of spatter, and a sooty mess.
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The electrical side:
The first problem is in the plug, the fuse is loose in its holder, the sort of problem that starts fires. Secondly, despite the speed control being housed in a metal box, there is no earth cable. I’m not an electrician, but I thought that this was illegal, common sense dictates that an earth connection would be a good idea, and the motor manufacturer does use an earth wire in their controllers.
Finally, the wiring in the mains connector to the circuit board is not soldered, so those wires could have come out at any point to make the casing live.
Whoever repaired this instrument before shouldn’t be trading!

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The Frame Repair
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I started by cutting away the bad repair to leave the two legs ready for a fixing bracket to be made.

At the same time I have to make a new square bush that prevents the leg from wobbling.
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Then the completed legs were assembled, the frame jury rigged into position, so that the new bottom bar can be cut at the correct length.
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Over the years I have done this countless times. My design has evolved, but the basics remain; the frame is the structural element, built to withstand the rigours of use. The keyboard bed just sits on top. The reason is simple – its more expensive to repair the keyboard bed.

Once the bottom bar is fitted, and the rest of the frame components made, everything is assembled ready for welding.

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Finally I need to make a new rod to connect the damper to the pedal, to replace the sorry example that was on the instrument.

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Job Completed
Here is the finished article; new base frame, new motor and controller, new damping mechanism.
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