May I ask if one of the more knowledgeable members knows if there is a difference between the 'internals' of the AT VM540ML and the VM740ML, or is is the difference just in the material of the external 'body'?
I originally purchased a '740' direct from AT, and then later after reading about the RigB 'bodies', I purchased a RigB bodied '540' from Simon which I found was much easier to mount because of the 'threaded' RigB body.
I find 'facebook' rather 'klunky' to use, but Simon responded quickly to my initial enquiry and forwarded a '540' with a black anodised body.
Later I ordered and received a 'red' anodised RigB body for my '740', but although the fitting instructions were straightforward, I decided to return it to Simon along with the cartridge to have the new 'body' fitted.
I mounted the '540' onto a Tabriz, but currently I'm using the '740' mounted onto an A.O. 'UniArm' / PTP6 Lenco using a Graham Slee 'Accession' MM phono stage.
I cannot really comment on any perceived diferences in sound between the two, given that I've spent more time 'fiddling' than listening - I decided that I first needed to source additional 'armboards', an MM phono stage, and finally both arms needed new tags fitting.
Regards
Mike K.