Supersvar, tack så mycket.Här är ett bra svar från WUS. Top Grade var standard initialt men för att kunna motivera prisskillnad till 656 valde man Top Grade till 656 och nedgraderade till Elabore i 556, men man har senare återgått till Top Grade igen. Det inlägget är från 2010.
http://forums.watchuseek.com/f24/grade-2824-2-a-341675.html
"I have an update that should settle most of your questions. I visited the Sinn factory today and asked one of their Master Watchmakers which grade ETA movements were installed in the 556 and 656 models. He said initially both came with the Top grade, but they eventually began using the Elabore grade in the 556 with an option for the customer to upgrade. This change was designed to move the 656 up in the product line (and justify the price difference). He said recently they decided to go back to using the Top grade in all watches. I asked if there were any way a customer could tell which movement came in their watch and he said no, they all pretty much look alike with a few subtle changes that only a watchmaker would be able to identify. He also said the Top grade movement had no more decoration than the Elabore. If you have a question as to which movement you have, contact Sinn with your serial number."
Finns även bra svar på den frågan i tråden. Inlägg #4.
"One workhorse of the ETA mechanical line is the ETA 2824-2, The 2824 is an automatic winding, twenty-five (25) jewel movement, available in four executions or grades: Standard, Elaborated (improved), Top and Chronometer. The key components which differ at the line of demarcation between Elaborated and Top are the barrel spring, shock protection system, pallet stones, balance wheel & hairspring and the regulator mechanism. To illustrate the differences in accuracy garnered by the successive grades, consider the following specifications:
The Chronometer grade must meet strict standards prescribed by the COSC. Chronometer grade movements are serial numbered as that is a requirement of the certification authority. Moreover, it should be noted that the degree of decoration on the movement's parts, generally only an aesthetic improvement, increases as well with the grade."
- the Standard grade is adjusted in two positions with an average rate of +/-12 seconds/day, with a maximum daily variation of +/-30 seconds/day;
- the Elaborated grade is adjusted in three positions with an average rate of +/-7 seconds/day, with a maximum daily variation of +/-30 seconds/day;
- while the Top grade is adjusted in five positions with an average rate of +/-4 seconds/day, with a maximum daily variation of +/-10 seconds/day.