Loricraft Garrard 301 to Dobbins Sp10 Mk3 - What can I expect ?

You might want to audition a Kenwood L07D, before you conclude you don’t like DD. Like other turntable drive systems, not all DD turntables exhibit the same SQ coloration, or lack thereof. Because you’re really saying here that you prefer a certain coloration of the 301. Not that there is anything wrong with that.

Hi lewm, I like the 301, Lenco L75, EMT 930, Rega, Nottingham Analogue, Dr.Feickert, Bergmann (latest model), Avid, Well setup LP12 and many more record players. All of them sound different but none of them exhibit the kind of electronically controlled flow I hear from Technics or even the EMT DDs. Whether Kenwood would cure it, I dont know. I will wait for a time when I get to hear it.

Having said that, I would agree that Garrard is not tonally studio neutral. My 301 is highly updated with some good tweaks. Yet it is not dead neutral. Lenco is better in that aspect. 

There are families of DD turntables, just as there are families of belt-drive and idler-drive types.  You auditioned only one "brand": Technics.  First of all, I find it hard to believe that you didn't hear substantial differences between the 1200G and the other two and between the Mk3-based Dobbins turntable and the Mk2 with no plinth.  The 1200G uses a coreless motor, which makes it fundamentally different from its forebears.  The Mk3 in any iteration should blow away the Mk2, let alone a Mk2 with no plinth.  I easily heard big differences between Mk2 and Mk3 in similar slate plinths, in my system. However, it's possible that all 3 take the Technics approach to servo control, which is very tight.  I don't like to think so, but perhaps you are "hearing" that tight control of platter speed that results.  There are other DD's with coreless motors and "looser" servo feedback mechanisms, like the Kenwood and maybe the Victor TT101 (which would have to be re-plinthed or the plinth modified) that you might find more like your 301, but better.  And there's also the Luxman PD444 and the Yamaha GT2000X.  So, you have DD's with iron core motors vs coreless motors, DD's with heavy vs light platters, and DD's with varying tightness of the servo control mechanism.  Each of these design choices makes a difference to SQ.  Not to mention the effects of plinth, tonearm, cartridge.  Generalizations are hazardous, because they make you stop thinking.

One important difference I missed out is, from 1200G to Sp10 Mk2 there was a marked increase in slam factor. 

Interesting. I run 2 different AudioGrail 401s. One is in a slate plinth with new 3rd party platter and idler. The other with original platter and new idler in a birch ply plinth with walnut top. Both sound great. Extremly musical and every record sounds great. The slate version is faster and to my ears, more neutral and transparent. The benefit of speed is critical in preserving the clarity in a way that mere detail does not. I heard the new SP tables in New York and prefer my Garrards. Obviously, there were many other factors but what was missing was a musical rightness that you have expressed.