@mijostyn Some sites show 1980 some 1981

General

• Manufacturer: Luxman
• Model: PD-300
• Type: Turntable without tonearm, with built-in manual vacuum platter suction
• Years of manufacture: 1981 - 1985
• Made in: Japan
• Color: Silver, Wood
• Remote control: -
• Power consumption: 15 W
• Dimensions (WxHxD): 490 x 200 x 390 mm
• Weight: 18 kg
• New price approx: 163,000 yen (Japan, 1981), about 2,500 DM without tonearm and without system, with Elac ESG-796 H 30 (according to Stereoplay 11/81 + 1/83 top class group 1) 3,150 DM market price.

Vinyl Engine says

Luxman PD 300

Belt Drive Turntable (1982-1984)

An AI search engine gives this answer

You’re right; there seems to be some confusion around the release date of the Luxman PD-300. While many sources cite 1975, others indicate it was introduced in 1980. It’s not uncommon for vintage audio equipment to have discrepancies in dating. If you have a specific source in mind, I’d be happy to help clarify further!

So far even the latest search date slightly predates the SOTA Star Sapphire which is 1984.

Steven W. Watkinson, Various | Sep 5, 2008 | First Published: Feb 5, 1984 The SOTA Sapphire was the first, and the most successful in terms of sales, of the new generation of high-end American turntables.

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release date of sota star sapphire

Copilot

The SOTA Star Sapphire turntable was introduced in 19841. It was an advancement over the original Sapphire model, featuring vacuum clamping to further reduce vibrations and improve sound quality.

Except in the case of my Star Sapphire III, the vacuum clamp introduced a faint dull haze over the music. Sounded better with vacuum off.

@lewm Ah yes! That was an observation that others had about the early tables. I do remember one reviewer mentioning this also, and he found the best setting for him was 1/3 of the dial on vacuum pressure. 

The new tables do not allow you to adjust pressure, there is a factory algorithm followed. There is an initial pressure applied to clamp the record and seal it, and then it is reduced to a maintenance level. On my Cosmos you have to remove the air hose to get the table to play without vacuum and I did that early on. I never noticed a degradation due to the clamping of the record, if anything I achieved improved resolution and fine detail in playback. I am satisfied with how the system works. 

In terms of who did vacuum clamping first, what about Micro Seiki, and what about the Audio Technica vacuum mat? Where do they fit in historically? There’s also the Victor TT801. Most likely that latter TT predates SOTA, but I don’t know for sure.

Incidentally, I think the vacuum strength on my Series III was already internally regulated. I don’t recall being able to adjust it.

If all aluminum I think there was a Supermat that was used to damp it.

@neonknight The Gen 1 Sapphire did not use the 'Supermat' as I told you earlier. Here is more information:

The Supermat was designed by Warren Gehl of Audio Research (although years prior to his employment there). Sumiko owned SOTA at the time they acquired rights to his platter pad, which was dubbed the 'Supermat'.

Its first appearance on a SOTA product was on the Cosmos. After serial number 100 they changed the formula.

The Gen 1 Sapphire predates this period so did not use the Supermat.