Buy 12ax7 tube

Go to Brent Jesse Tubes and read... Tubes are heavily researched for character and tested. He stands behind his inventory.

I use Telefunken smooth plate on my McIntosh C2300 MC phono stage and Gold Lion gold plated pins, cryogenic treated for my line stage.

Check out Doug's Tubes and Upscale Audio.

+1 to Loweider57, he is spot on with all advise . At your price point Tungsram and EI are your best bet . Telefunken is the best overall . Once you go Telefunken, you’ll never go back . I have a pre that takes 2 12AU7’s . I have about $ 2500. invested in 12AU7’s alone  . From RCA to G73-R Telefunkens. The smooth plate regular grade Telefunkens are the best bang for the buck . When looking,  Tungsrams might be relabeled as RCA or Raytheon. If you want Telefunken sound but a little brighter , try the Nickel plates . Happy Hunting , Mike. 

@lowrider57 can you suggest me a good power strip? I see they say connect your amp directly to the wall socket ac,how can it possible when i should use a power strip?
Sorry for my noob questions

And another question
If i can change my speakers with a good audio physic or dynaudio speaker or buy good power strip+power cable+new tubes+usb cable

Which one is better choose?
I just can select 1 option!