the home of the turntable

Library / Psionic

Psionic LOCI

Parallelogram Motion Tonearm

review this tonearm add a review

psionic loci tonearm
Psionic LOCI


The Psionic Corporation is pleased to announce the development of a new tonearm: the LOCI. This reasonably priced tonearm owes its extraordinary performance to several features.

Since it is difficult to cut the vertical component of a record groove's oscillation straight up and down, it is cut at an angle called the vertical tracking angle (VTA). Many tonearms can be adjusted to change the VTA because small errors in VTA cause significant deterioration of sonic accuracy. Different record labels, alas, use different VTA settings, so the LOCI adjustment for VTA is calibrated: it can be reset to a specific VTA for each record. Only the LOCI catalogs the correct VTA settings for over 100 different record labels.

Low bass reproduction requires that a tonearm have high mass in the horizontal direction of motion. Tracking all the big and little warps on a record requires that a tonearm have low mass in the vertical direction of motion. The articulated vertical motion of the LOCI allows the light front portion of the tonearm to move to accommodate vertical motion but enables the entire tonearm to move to accommodate horizontal motion.

Previous attempts at articulated vertical motion in tonearms have suffered from speed changes as the cartridge moves up and down small warps. This annoying phenomenon is called warp-wow and does not occur when the LOCI tonearm is used because the cartridge motion is vertical when warped records are played. The parallelogram linkage also maintains a constant VTA as a record is played so the sound does not vary in quality as the record turns.

The laws of physics tell us that any single support mechanism, such as the arm tube, will have some frequencies at which it will resonate and colour the sound. The LOCI has two arm tubes of differing characteristics, so that the colourations of one tube will be cancelled out by the other. Two arm tubes also provide a more rigid support for the cartridge mounting posts.

Each LOCI tonearm is machined by hand to tolerances of 10 microns (.0005 inches). Materials are chosen on the basis of listening tests as well as handbook data and machining experience. The RW-MS1 cable used in the LOCI has the lowest sonic colouration of any interconnect cable available to date.

The LOCI can be installed on standard armless turntables available today. It is designed to elicit maximum performance from any quality cartridge and turntable on the market.


brochure  English - soundbug1

instruction/owners manual  English - soundbug1

vta settings  English - soundbug1

Please login or register a free account in the forum to download files

If you have additional documentation please consider donating a copy to our free archive.

NOTE To view PDF files the latest version of the official acrobat reader is required.

Psionic LOCI owners manual, service manuals and schematics are for reference only and the Vinyl Engine bears no responsibility for errors or other inaccuracies. The PDF files are provided under strict licence. Reproduction without prior permission or for financial gain is strictly prohibited. This website is not affiliated with or sponsored by Psionic.