Mk4A or MK4B? That is the question.

[kungfujews]

Hello everyone - Just a querie - I'm the proud owner of a second hand Mk 4 short body combo (200W EV speaker) just bought last week. However I don't know whether it's a MK4 a or a MK4b...Can anybody out there tell me the difference? By the way - it's the best tone I've ever had - and I still don't know how to use it properly! Cheers. :?

 

[Mongo1]

The quickest and most obvious differentiation would be in the effects loop.
MKIVa has two separate loops (switched and normal). Jacks arranged in a square
MKIVb has one loop (single send and two returns). Jacks arranged in a triangle.

There are many other subtle differences, but that one should identify it.

 

[kungfujews]

Thanks for the tip Mongo 1 - the loop is indeed arranged in a triangle with the single send and two returns, so it looks like I've got the MK4b. Thanks again - it's nice to know!