Hi, trying to just lay the ground work for a geneology of the Sony slim Walkmans EX/FX/GX that ended with the WM-EX651, or round abouts there. I am trying to trace the design back to its roots, to the first true clean sheet design, ie. not based on anything. My very rough timeline appears to be... the very homogeneous WM-EX670-type slim lines based on... older EX models like WM-EX633, based on... even older EX models like WM-EX80, based on... WM-701c, based on... WM-103 through -609 (first solenoid based Walkmans?), based on... WM-100-type, based on... WM-10, which doesn't appear to have any similarity with WM-2 based or TPS-L2 based Walkmans at all. So is is this a good basis for a lineage? If not, why? (be nice!)
The WM-10 doesn't have any similarity with WM-2 or TPS-L2 indeed. The TPS-L2 is based on TCM-600, while later units (WM-3, D6, D6C) are based on TPS-L2 mechanism. The disc drive D6 and D6C have a different capstan drive, but it's essentialy the same mechanism. WM-100/200/500/600 series I agree are based on WM-10/20/30 series, although the differences are significant and the 2 series share little between them. In regard to the WM-700 series however it's hard to find any similiarities (apart from capstans/flywheels) with any of the previous series. EX80 is indeed essentially same mechanism as 701C, but it's also very different than any 3 digit EX. Would be curious what your rationale is in making this lineage of devices. What are the criteria on which you decide unit A is based on unit B ?
Thanks for giving me your thoughts. So when I say "based on", I am thinking from an engineering design perspective. I do work that is a little different now, but when I was designing clutches that had a fairly short development cycle, we would have clean sheet designs, "like-buts" which were very similar to an existing model "but" with one or a few changes, and lots in between. Sometimes sharing a lot of part numbers, and sometimes packaging dimensions were different, so no or few part numbers were shared, but mechisms and concepts were copied. So when I say that the slim line EX models are "based on" the 701c mechanism (or a derivative of it) I am thinking that the mechanisms are similar enough, with the solenoid allowing rotation of a selector wheel that moves gears via plates that pivot on rivets, that it seems that the engineers of the slim line EX models must have been using the 701c (or a derivative design of it) for reference. And now that brings me back around to my question... is that criteria a stretch to say that the WM-EX651 has lineage all the way down to the WM-10, or are there some jumps, like from the WM-100 type models to the 701c, where you would say "no, that is a clean sheet design"?
I'm thinking from the same perspective, so we are on the same page here. Here the question is what the threshold of "similar enough" is. In my opinion the fact that a basic principle (like camgear + solenoid) is used in a mechanism means little as the vast majority of slim autoreverse walkmans used a similar basic principle. For example I can't say that AIWA HS-PX477 is based on Panasonic RQ-S25 just because they use camgear + solenoid or because they use a disc-type 3-phase brushless motor. As for a clean sheet design, in the purest sense very few designs out there are truly "clean sheet", because apart from parts designed in-house, most designs also use off-the-shelf parts. For example: re-using a generic off-the-shelf IC like NJM2063 Dolby B decoder means little. That IC was used in WM-DDIII and also in WM-702 (which have nothing in common), but it was also used by other brands. But even proprietary ICs (for example CX20085 Dolby B decoder) were used in unrelated walkmans: WM-DDII and WM-10. So just based on this alone I can't conclude that one is based on the other. However if they would be re-using an entire design arhitecture (even if this arhitecture was based itself just on off-the-shelf ICs) with just small modifications, then it's obvious A is based on B. In regard to the question if there are jumps, I think there are. Specifically around the 600 to 700 series transiston and around 2 digit EX - 3 digit EX. EDIT: Seems the 3 digit EX series are very similar to EX52, EX53/57/59.
