Picked up a Mark IIa today, couple of questions...

[user 19917]

To me it looks like a CTS speaker,they used to have those square magnets, I had a couple of them in a Fender Twin reverb ,back in 1975.

 

[igfraso]

The 67 code means Eminence.

 

[arispouncey]

It only makes a pop if you are playing at the time you are switching channels. If you are not making any sound at that time, it won't make any pop.

I don't think there is any mod in Mesa to fix this for the Mark II-A and II-B.

see mine doesnt do that unless i have the gain set really low. at high gain it doesnt pop at all. i bought it used so the previous owner might have gotten LDR's or something but at low gain settings it does pop.