What 12AX7s should I swap out for fun on my Mark V?

[Jimi D]

Hi guys,

I've had my MV head since christmas (a gift from my lovely wife!) and I'm still grinning ear to ear every time I plug into it... I've been thinking of swapping out a couple preamp tubes just to hear what difference they may make, and I'm wondering which ones are likely to have the biggest impact on my tone... I was looking at the tube chart in the manual and I know that V1 is the first one I want to play with, but after that, I'm not sure if I want to try swapping out V2, V3 or V5... Any thoughts? Also, I'm looking at where V1 is situated and I'm wondering how anyone can get their hand in there - do I have to pull the chassis just to swap tubes? Has anyone tried pulling the 'verb tank and going in through the hole cut for the tank in the bottom of the cabinet?

thanks in advance for any suggestions/advice

 

[LPJunky]

I put a blanket on the counter and put my head upside down. I swapped V1 and a couple of others (can't remember). I also changed to El34s. Apart from the fact that the tubes are sunk in, all went well. I'm always a bit nervous since you don't see the pins at all so I make sure to notice the orientation of the missing pin for preamp tube. You don't want to force it in and bend anything since the tube socket is lower by about half an inch from the metal sheet surface. Are all mesa built like that? My other 2 amps have socket mounted flush so its easier to see that everything is going in as it should. For the power tubes no issues since yoy have that plastic dent to guide the tube in the socket.

Congrats...