Yes there are.
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No the stock ones are 6DJ8 and not 6SN7.
Improving the high end on SA100 (stock, based on my experience with the SA220) means u need to replace the coupling caps AND swap out the 6DJ8 with a something that has sparkle like the Telsa (new JJ or NOS)
Now if your SA100 has been "altavista'ed" thats another story.