Tubes for VTL S200

Thank you! 

I bought them from Sweetwater but haven’t gotten them yet. I like the S200 very much but feel that with other tubes it can sound even better.

Also looking for black plates. Should all 4 be same model and brand? Or two and two?

NP.

Have not purchased tubes from Sweetwater so no idea on what type of testing they may or may not do. 

As for input tubes you may want to look for either UOS or NOS Raytheon, RCA or sylvania black plate 12AT7s or 12BH7s (on the current model of S200). Depending on which version of S200 you have the first tube will likely be a 12AT7 but the 2nd tube can vary. 

The tubes don't have to be the same brand. 

When buying older tubes just be sure to clean the pins. Any pin oxidation can lead to noise. 

If you are still using the factory installed input tubes, they were usually JJ. They are ok but not the greatest. 

Thank you.

Yes I am still using those factory tubes. The second is 12BH7.

you are welcome. You may want to consider looking on the bay for Raytheon 12AT7WA or GE 6201s, or Sylvania 6201s (6201 is the mil spec version or industrial version of the 12AT7). For the 12BH7s, lots of vintage options from GE, RCA etc. The First input tube (12AT7) can have a significant impact on the sonics of the amp. 

JMO, but think almost any vintage input tube is going to offer better sound than current JJ stock.