Audio-Technica - AT-CAP4 Multi-Function Cartridge Alignment Protractor + Stroboscope Disc

A full-size 12-inch setup disc with four alignment geometries on one face and a 33/45/78 stroboscope on the other.

Most protractors give you one geometry and expect you to agree with it. The AT-CAP4 prints four — Baerwald, Löfgren B, Stevenson and UNI-DIN — so you can choose the one that suits your arm and your listening. Audio-Technica's own guidance: Baerwald for broad distortion minimization across all genres, Löfgren B to favor the middle of the record surface, Stevenson for classical and jazz where the critical material runs close to the label, and UNI-DIN for modern rock and pop with mid-to-inner-groove content.

Between them the four geometries cover tonearm effective lengths from 200 to 250 mm, and there is a separate overhang scale for stylus-to-spindle distances from 10 to 20 mm. The disc is a full 300 mm with a 7.3 mm spindle hole, so it sits on the platter exactly like a record.

The reverse face is a stroboscope for 33-1/3, 45 and 78 RPM, printed with both 50 Hz and 60 Hz rows — in the US you read the 60 Hz row. One thing to know before ordering: this is a mains-lit strobe, so it needs an incandescent bulb or a dedicated strobe lamp. Modern LED and CFL room lighting generally will not give a usable reading, and no light is included.

Features

• Two-sided setup disc: cartridge alignment on one face, speed stroboscope on the other
• Four alignment geometries in one tool — Baerwald, Löfgren B, Stevenson and UNI-DIN
• Covers tonearm effective lengths from 200 to 250 mm
• Overhang scale for stylus-to-spindle distances of 10 to 20 mm
• Strobe side covers 33-1/3, 45 and 78 RPM at both 50 Hz and 60 Hz
• Full 300 mm disc with a 7.3 mm spindle hole sits flat like a record
• Light at 165 g and 2 mm thick — stores flat in a sleeve

Specifications

• Type: Two-sided cartridge alignment protractor and stroboscope disc
• Alignment Geometries: Baerwald (Löfgren A) and Löfgren B for 222-250 mm effective length; Stevenson for 200-230 mm; UNI-DIN for 220-240 mm
• Overhang Range: 10-20 mm between stylus tip and spindle
• Stroboscope Speeds: 33-1/3, 45 and 78 RPM
• Mains Frequency: Both 50 Hz and 60 Hz rows printed — use the 60 Hz row in the US
• Diameter: 300 mm (12″)
• Thickness: 2.0 mm (0.079″)
• Spindle Hole: 7.3 mm (0.29″)
• Weight: 165 g (5.8 oz)
• Important: The stroboscope side requires an incandescent lamp or a dedicated strobe light, which is not included. LED and fluorescent lighting will generally not produce a readable pattern