Short tips which will help you easirer to set up turntables, tonearms and cartridges.
Please also look our KAA 2016 elswhere for theoretical and practical information!
A.Cartridges & tonearm set up mystiques revealed:
Importance of overhang is absolutely none. This is a distance how much is diamond tip over the centre of the record from direction of the horizontal bearing of the tonearm. It is only a starting point of setting up tonearm & cartridge tangential geometry for pivoted tonearms. Optimal overhang does not mean that cartridge is properly set up in tonearm. Do not be mislead with precise figures below 0.50 mm. You can not see or adjust that precision anyway.
But if you use two zero point protractor, when both points are optimised that also automatically means that all parameters ( optimal tangential geometry with minimal tracking error distortion) is optimal, regardless if you start with not correct tonearm distance position or how tilted is cartridge body in the headshell. You simply align cantilever and diamond tip on two zero point protractor. How to simply achieve that- visit our web site Kuzma Ltd for details. This will insure you minimal mistake in tracking.
If you use more sophisticated protractors with single null( zero) point alignment on the tonearm distance from pivot to spindle- be aware that a small mistake in distance set up will create bigger error and you will not be aware of it and you can only test it with two zero point protractors with correct geometry ( Baerwald, Lofgren...). Some single point protractors are not rigid enough- flimsy ( 1-2 mm movements between construction parts ) and thus can create very big error. Which can be easy 1-2 deg off in inner null.
2. Bias: soon
3. VTA ( SRA):
When you set up VTA with microscope and you set up diamond tip at 92 deg do not be so precise. It is a starting point and then listen at least 1-2 deg up or down. When you measure angle on static diamond tip be aware that rotating record will pull along diamond tip with cantilever- this angle is in the region of 0.5 deg for low compliance MC cartridges. So aim for 92.50 deg.
Changing VTA( SRA) by changing tracking force (VTF): Low compliance MC cartridges has stiff cantilever suspension called compliance( CU: 5- 20 ). MM cartridges has softer suspension ( CU 30-50). When cartridge touch the record due traacking force cantilever will be pushed up and SRA will change. This deflection is in the range of 0.5 mm which means that SRA changes for about 5 deg when VTF goes from 0 gr to 2 gr. So when you change tracking force you change SRA( VTA) thus effecting position of diamond profile in the record grooves and coils positions in magnetic field. In practise means this: changing tracking force in low CU MC cartridge for 0.1 gr effects SRA ( VTA) for 0.25 deg. This is the same if you would raise or lower tonearm's VTA in 230 mm ( 9 inch) long tonearm for 1 mm. So use this for very small VTA changes when you experiment.