My current setup is a Topping DX7 dac/amp with hifiman he-400i using a balanced xlr cable. How can I get tubes into this equation at a reasonable price? I don't want tubes all the time, just on occasion.
I have a little bear p7 but it gives a buzz and I don't know how to fix it. *edit: I got the little bear to work with an aux cord, no need for a tube source now