With the Series I, if you're looking for the _Ultimate_ in transparency and dynamics, IMHO go for an original NOS pair of Telefunken ECC803S or ECC802S (lower gain, less audible tube "rush" if you're a nearfield listener, but less dynamic than the 803).
They won't come cheap though, a good pair of 803S will set you back about a grand and a half. The 802S about half that.
If you're not keen on spending that much, a good NOS Tesla ECC803S pair will come close, though not nearly as transparent IMHO.
They won't come cheap though, a good pair of 803S will set you back about a grand and a half. The 802S about half that.
If you're not keen on spending that much, a good NOS Tesla ECC803S pair will come close, though not nearly as transparent IMHO.