I managed to change the tubes without removing the chassis from the box. I mentioned removing the chassis from the box to do a once over of the amplifier; wipe down smoke soot, dust and tighten the transformers hardware (that thing was rattling around, I still am amazed at how big it is). I measured my RCA EL 34's at 4.25" from the plastic key hole tip to top of the tube.
I have a couple of 6AV5GA tubes in boxes and those seemed to be at the 3.75" you were referring to. I think there's plenty of room to put some bigger tubes in there if needed too. When I pick up a set of 6550's that'll be the defining factor.
Thank you for the elaboration on the tube sizes.
Tonight a buddy of mine who plays bass will use this PLUSH 4KG at rehearsal. After practice we will be able to determine if it is up to par to play out with for bass. The bassist is used to playing solid state gear, so I hope that little bit of tube lag doesn't turn him off. He plays a GK 800RB and is used to the fast response of it.
I have a couple of 6AV5GA tubes in boxes and those seemed to be at the 3.75" you were referring to. I think there's plenty of room to put some bigger tubes in there if needed too. When I pick up a set of 6550's that'll be the defining factor.
Thank you for the elaboration on the tube sizes.
Tonight a buddy of mine who plays bass will use this PLUSH 4KG at rehearsal. After practice we will be able to determine if it is up to par to play out with for bass. The bassist is used to playing solid state gear, so I hope that little bit of tube lag doesn't turn him off. He plays a GK 800RB and is used to the fast response of it.

