Will using a different tube (or tubes) for the Reverb make a difference in the way the reverb sounds in a Twin Reverb. If so, will it also affect the general tone? Additionally, if different tubes create different reverb characteristics, are there any predictable changes. I think I've read you use something like an AT or AU or something instead of an AX (or whatever it is) to make the reverb onset different. For example, right now my reverb is basically off until I get to right before 2 on the dial, and after about 2.5 I'm firmly in surf territory. It would be nice to have a "wider spread" - so say what happens from 2 to 2.5 now goes from say 1 to 5 or so instead. I don't have a problem with the tone or the depth of the reverb per se but I've heard Deluxe Reverbs with a "swimmier" (surfier - more like the 63 stand alone tanks) verb - would any tube swaps help? Also, I was using verb on the amp, and boosting the volume into the amp (which on a TR just gets louder). When I had this louder volume going into the amp (from an output knob on a pedal board let's say) it seemed to "smack" the reverb in way that I found unpleasant. So again I'm wondering if any tube swaps could help, pardon the pun, rectify that. Finally, I might ultimately consider swapping out the reverb tank if that could make a difference. But I guess what I want to know is if stock tanks are generally hit and miss - you may get an awesome sounding on, or you may not - or if they all do pretty much sound the same (within a reasonable range). I'm sure there are manufacturers out there who make replacement tanks. But I guess if the tube plays a bigger role in the overall - response - that's the word I'm looking for - the response of the verb, that would be the obvious place to start.