Unsure of what preamp tubes go in what sockets in C+?

[markchatwin]

On a happy note I just got my C+ from FEDEX and the gentlemen who sold it to me smartly took the tubes out for safe shipping. The preamp tubes were wrapped in bubble wrap and there were no instructions as to what went where. There were 4 tubes and one metal housing shaped like a slide for playing "slide" guitar (ie - a cylindrical silver metal tube presumably a sleeve for one of the tubes). As for the preamp tubes two of them were exactly the same with writing on them (I think 12AXR7), one had like a rubber like sleeve around it and said something like AXR7, and the final one had no writing on it at all, and of course then there was the metal silver tube. All the tubes were the same size but the differences were the one with the rubber sleeve and the one without writing on it.

Inside the amp there seemed to be 4 sockets behind the power tube sockets running left to right. Does anyone know what tubes go where? Thanks...

 

[markchatwin]

I just went to Mesa website and I got the name wrong, it is 12ax7. From left to right as your looking from the back side in Mesa calls the sockets "Front Row" V4, V3, V2, V1. These are the preamp tubes I assume. There is a V5 but it is located in the "Back Row" with the Power Tubes. All the tube sockets, V1thruV5, say 12ax7. Does this mean even though my tubes look different they are all 12ax7 and I can put them anywhere? A friend of mine said that one of them is a phase inverter tube and is likely different...

 

[madryan]

The tube closest to the input jack is V1. The one furthest is your PI and might be a 12AT7, at least that's what I always run there. V1 and V2 are the ones that are going to make the most difference in your sound so I'd throw a 12AT7 if you can get one in the PI spot, some solid 12AX7's in the rest and then hot swap tubes through V1 and V2 till you find the ones you like best.

Hope that helps.

 

[dodger916]

Hey Mark: I'll call you tomorrow.

You can put any of those tubes in any slot. As Madryan said, some people use a 12AT7 in PI (I do). It's a lower gain version of the 12AX7, so it tames the amp a bit. You can run the 12AT7 in any other slot as well. It's also recommended that the PI tube (V5) have balanced triodes.

When I make it up to Syracuse, I'll bring some VOS tubes to play around with. There is a difference.

Frank

ps: Congrats on the BOTH babies!!