Since you mention it.JackOfAll wrote:Swapping the 6N6P for an ECC99 is a more subtle change than swapping out the ECC88. My recommendation would be to "roll" that first before thinking about ECC99's.
I've been using Tesla E88CC tubes in place of 6n6p-ev for a week or so.
A bit more detail, a bit more realistic sounding. A bit harsher, but i'm adjusting to that.
Didn't like them in my cheap headphone amp, and actually preferred the original Chinese equivalent 6n11 i think.
However in the preamp they're not bad at all.