Reed 3Q tonearm working principle

Laser-adjusted tonearm operation is based on a level principle and helps to determine when tonearm mounting surface is parallel to the headshell (cartridge mounting) surface.

When using laser-adjusted tonearm, it is possible to adjust VTA and azimuth very quickly, comfortably and precisely after changing LP with different thickness or switching cartridges.
Laser beam a is adjusted so, that when it points to the point A on the scale c of the headshell b (Fig. 1, Fig. 2), the tonearm armwand is parallel to the tonearm mounting surface and a platter, i.e. VTA is adjusted to zero position.

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Fig. 1. VTA adjustment using laser (scheme)
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Fig. 2. VTA adjustment using laser (photo)

If laser beam points above the point A (Fig. 3), tonearm must be lowered until the beam appears at the point A. If laser beam points below the point A (Fig. 4), tonearm must be raised until the beam appears at the point A.

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Fig. 3. VTA adjustment using laser -
tonearm too high (scheme)
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Fig. 4. VTA adjustment using laser -
tonearm too low (scheme)

Headshell (cartridge mounting) plane is parallel to tonearm mounting/platter plane if, after turning the tonearm, laser beam a points to the point B, (Fig. 5, Fig. 6). That means azimuth is adjusted to zero position.
If laser beam does not appear in point B, azimuth must be adjusted accordingly.

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Fig. 5. Azimuth adjustment using laser (scheme)
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Fig. 6. Azimuth adjustment using laser (photo)