Mark iv Blue LED?

Ive seen pictures of mark iv's new and old and have noticed the newer looking ones have a blue LED the amp i just bought of craigs list ( A mark iv 1x12) looks like the newer version and has this blue LED does any one know if it would be a A or B?

There are more differences to tell the two versions apart besides the blue LED. That seems to be a good indication, but ever better - is the FX loop mono or stereo? Three jacks in a triangle is stereo and thus a 'B' model. Four jacks in a square shape is mono and thus an 'A' model. Don't get too caught up in the whole A or B thing. I've owned both and the differences are really nothing to write home about IMO.

Congrats on your new amp!

Thanks! It has the line loop so its a B was the blue LED a recent thing before they got discontinued?

Yeah, I think so...

They were available as early as 1991, one of my C+'s was serviced in 91 and had its amber light replaced with a blue one. Not sure when they cut over to blue permanently in the Mark IV, probably when the amber ones ran out.

My Mark IV is a 92 and it has the blue LED, too.

Interesting... !

do they still make the a and b version or just the b now?

1vic1 said:

do they still make the a and b version or just the b now?

Click to expand...

Neither they're out of production.
It's only the Widebody combo and Medium head that have the blue led.