Tube recommendations

Never used ECC83 or ECC88, these are different type of tubes than ECC81, they are NOT interchargable and this is all you need to know. 

Dear @infection : """  As I'm new to tubes which tubes would you recommend to be a significant upgrade? """

Why so fast did you decided to change the original tubes?, this is as when you bougth a cartridge and one month latter you want to up-grade it or change it. Something must be wrong down there phono stage.

R.

No rush...I just thought I'd inquire for future reference.

I suggest you call Andy at Vintage Tube Services. He can help you with tube selection

While I'm guilty of tube rolling and have favorites, without knowing the pre you have and the type of sound you prefer any advice I (or any of us) could give would be a shot in the dark.  So what pre do you have?  And what change in sound are you looking for?  If you call Andy at VTS, he can certainly help you, but you'll need to answer those questions for him  as well.