Hello all! At the advice of many of you helpful people here I recently became the owner of a Mesa Mark IV. Amazing amp and all I could ever want! I WILL make a NAD I swear!!

However, before I can do that I will need to obtain new tubes I believe. The amp recently started making a sound that is like a combination of white noise and hum. Gets louder with more gain and as the amp goes louder. Definitely the amp, unaffected by cable change, guitar change, guitar volume etc. I think this is the sound of a tube going?

I tried the method of pulling one tube at a time out, and it went away when I took out the V1 and V2 tubes, however the amp also didn't make any noise from anything else (i.e. guitar) when I did that. I didn't try the power tubes yet, but could it also be those? What can I do to safely find out myself? (short on funds, ideally wouldn't want to take it in but will if it sounds like I have to)

If I need new tubes, i read I need to buy tubes biased to the universal mesa standard or whatever so I need recommendations of a good vendor and how to go about doing this. The tube sites I went on didn't seem to have an option for this.

If you can help thank you very much!! I need to get this solved asap, big gig next weekend. (note: I bought a single 12ax7 groovetube [was the only option at local store] and put it in V1 when I thought it was V1, but it didn't make a difference)
Find a set of JJ tubes for your model of amp. If you tell the vendor it is for a fixed bias Mesa they should have a set that will match well.

These guys are pretty good.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY