What is the diff between a studio 22 and a studio 22+ ???

[gomeshome]

I'm trying to learn what the physical and tonal difference is between a Studio 22 and a Studio 22+. Someone said it was the addition of a graphic EQ, but I see that the graphic EQ an option on the 22+, and have seen an ebay listing of a studio 22 WITH a graphic EQ. What is the real story?

Thanks!

 

[killerburst]

The PLUS has a lead master control and plastic rocker switches. 8 knobs on the front. The pre-PLUS has 7 knobs and metal toggle switches. EQ was an option on either.