hi,
i guess i know what you mean and it´s like this:
the jv5 runs an epson IH47V head ( oem-licensed only ) ... so does the jv33 ..
but:
on jv33 there is an option in the electronics missing to block other heads to be installed - so there are compatible ones existing !
on the jv5 it´s working - and refusing any head then the original IH47V
i installed several heads to JV33 / VJ and also JV5 so i know about..
best regards from germany,
yours jan