I bought a 1999 DRRI, all stock. Tubes looked old, the first playing test was so-so. Ordered a new set of tubes, JJ & Tong Sols mixed and I have a G12H30 heritage that at one time I had in a BDRI. I'm going to install that in the DRRI. I've read on this forum and others that some like the G12H30 and some don't. Well, it's paid for so it's going in. I found a nice paper that is on the net detailing a full over all of a DRRI with some of the known mods. I'm not going to do any of those until I get the speaker/tubes worked out. I am going to have to pull the chassis to be able to remove the speaker. The speaker won't slide off of the top stud, it hits the transformer. I've read about the different spacings for the new type speaker compared to the RI speaker. To remove the chassis is it just the 4 big screws in the top of the amp that hold it in?