The few scattered observations by Marx that gave credence to this idiocy are probably the most disastrous words in his collected works, for the position that technology is in any but utterly trivial ways any kind of "determinant of social relations" is about as profoundly un-marxist as it is possible to be.
Ellen Wood devotes about a third of her *Democracy against Capitalism* to a polemic against technological determinism, a view that she quite properly sees as simply denying history (including class struggle).
What I mean by trivial is that some level of technology is an obvious precondition for almost set of social relations one might name. It would be hard for example to imagine monopoly capitalism in a world limited to paleolithic technology. Big Deal. The use of technology is always determined by social relations, never the other way around. The apparent independence of technology under capitalism is a major element in capitalist ideology, probably related to what Marx called commodity fetishism.
Marxists (or perhaps one should say "Marxists") who adhere to some form of technological determinism usually are at heart believers in the 19th century doctrine of inevitable Progress (with a capital P). Perhaps that had its effect on Marx at the moment when he penned those silly remarks on the hand mill and the water wheel.