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Old 5th Nov 2012, 7:15 pm   #38
GP49000
Hexode
 
Join Date: Mar 2012
Location: Sonoma County, California, USA.
Posts: 405
Default Re: Garrard record player deck identification.

The Autoslim line was a great achievement for Garrard. It was inexpensive to produce, having many fewer parts than its predecessors the RC100/200 series. Key to this was its "single plate" operating mechanism. Whereas the RC100/200, and the RC80/88/Type A line had many levers operating from multiple cams and tracks on a rotating assembly driven by a pinion on the platter, the Autoslim had a simple cam wheel with only one track. Everything was driven from this one track, via a single plate on the underside. Nobody else could use this system; Garrard patented it.

The Autoslim line also was the first Garrard series able to play a stack of same-sized records of randomly mixed sizes. Competing against BSR's inexpensive models in the popular price range and as an OEM supplier for phonograph and radiogram manufacturers, Garrard had to match that capability at the same time minimizing its production costs.

The ability of the Autoslim chassis to meet the needs of medium-priced hi-fi systems helped Garrard expand its reach into those markets with a highly profitable product. Performance capabilities improved, too, particularly in tonearm tracking. At the time of the first Autoslim and AT6 models, it was hardly necessary for a home hi-fi record player to track at under three grams. But lower tracking weights soon became more important. Two aspects of the Autoslim design limited its tracking capabilities: the "friction link" by which the mechanism cycled the arm contributed an amount of drag to the arm's motion, and the automatic trip mechanism added its own friction. The trip mechanism was quickly improved with low-friction Delrin® inserts in which the auto trip slider, pushed by the tonearm, would operate. These were incorporated not just in the higher-end Autoslim models such as the AT60 and SP25, but also in all other models, as the change was made to the basic chassis stamping. The "friction link" was gradually improved to the point where, with a change in profile to reduce contact with moving tonearm parts, and a Delrin® pad to support it more freely, it hardly limited the tonearm's tracking at all. However, the Autoslim-chassis models never met the claims of Garrard's USA representatives, who claimed in catalogs that the 60 Mk II and SL65 tonearm systems could track and trip flawlessly at 1/2 gram; though the last models such as the SP25 Mk V could get close if optimally serviced and set up.

Through most of its life the Autoslim was idler-driven; but beginning in the late 1970s, the 125SB, 35SB and SP25 Mk V and VI belt-drive models were introduced. The Autoslim design was finally superceded by a mechanism that was even cheaper to build, the "Unimech" which will be discussed later.

Even prior to the acquisition of Garrard by its Brazilian importer Gradiente, assembly of some Garrard models and production of some parts had been moved to Brazil. Brazilian-built models were produced under both Garrard and Gradiente brand names.

Autoslim mechanism patent drawing
RC121D underside mechanism
Type A underside mechanism
AT6 underside mechanism. Note its relative simplicity.
Gradiente-Garrard 50SB, almost identical to SP25 Mk V.
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Last edited by GP49000; 5th Nov 2012 at 7:29 pm.
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