Tubes-store.com

I bought many 6C33C from them in 2 separate purchases.  First purchase 2 out of 10 tubes were defective, but they were quick to send replacement.  Second purchase I asked them to test before shipment and all arrived fine.

Shipping (to Taiwan) was expensive though, but overall cost is still significantly lower than buying from US retailers.

Nope, but should not be a problem if you always pay with PayPal for their goods (you are fully protected with PayPal buyers protection). International shipping is not a problem. Try it!