Ammonite Acoustics Improved Mounting Collar for Jelco Tonearms, Black
Ammonite Acoustics custom improved mounting collars for Jelco tonearms have been re-designed and are now even better and easier to use. Key improvements over the Mk1 collar include:
The central pillar hole now has a sharp side-cutout. This means that the arm pillar is now held gently, but firmly, against two vertical’knife edges’, so there is no longer any possibility of the arm pillar leaning to one side. If your armboard and platter are aligned to the same level plane, this new collar will guarantee that the Jelco arm pillar will be truly vertical to that plane.
The grub screw is still a large 6mm stainless steel item, but it is now longer and fitted with an integral nylon end stub.
The overall diameter of the collar is now the same as the standard Jelco collar. This means full compatibility with any armboard cut for a standard Jelco arm.
Why do I need a different collar for my Jelco tonearm?
Have you ever tried to set the azimuth of a Jelco tonearm correctly? Just when you think you’ve got it sorted, it’s off again! That’s because the standard collar, while beautifully machined, provides very poor vertical support of the arm pillar; and the tiny set screw typically pushes the top part of the arm to one side, almost guaranteeing that the arm will not be properly set up. The azimuth actually varies as the arm traverses the record, which matters a great deal with modern cartridges and stylus profiles. The custom collar gets around that problem by ensuring that the arm pillar will always be secured properly vertical, so setup becomes easy and repeatable. That means better musical reproduction.
Is the collar compatible with other tonearms?
The collar is fully compatible with standard Jelco collar mounting templates, and all Jelco manufactured derivatives with 18mm diameter pillars, including Audioquest, LAD, Ortofon, Roksan. Some Sumiko variants have a smaller 16mm pillar, so are not compatible.
The Improved collar is 5mm taller than the standard collar, and longer underneath for much better support of the arm pillar.
It is fitted with a large stainless steel M6 grub screw, with integral nylon stub to protect the soft metal of the arm pillar.
Supplied with a hex key for grub screw adjustment, and stainless steel fixings consisting of 25mm long M4 bolts with nuts and washers and hex key for arm height adjustment. If you purchase this arm mount with an AnalogueWorks turntable, we will provide appropriate bolts for fitting.
The custom collar is 5mm taller above the armboard than the Jelco original. Look carefully at your tonearm as it’s currently fitted to the turntable – if there is less than 5mm clearance between the top of the standard Jelco collar and the base of the arm rest plate as currently fitted to your record deck, it may not be possible to set the arm low enough with the custom collar, to achieve correct VTA, without recourse to a thicker platter mat or headshell spacers. It is possible to use thin metal shims between the cartridge and headshell to tilt the rear of the cartridge down a touch, thereby achieving the correct VTA without using different mats or spacers. Please ask us if you are unsure about this. In practice, the potential problem only applies to turntables with very low-profile platters, eg the Technics SL-1200; however suitable and compatible armboards are available for the SL-1200 from online sellers which allow the whole arm to be sunk low enough to ensure that correct VTA is achievable without any difficulty.
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