12au7 or 12ax7


I recently purchased my first tube amp a Primaluna Prolouge 5, the previous owner said the tubes were at the end of their life. I replaced the factory KT-88's with Tung-Sol KT-120' with which I am very pleased. My questions is which would give me the biggest sonic benefit replacing the 12au7 or the 12ax7? Both will be replaced in time which do you think I should do first?
lardawg

Showing 2 responses by rodman99999

What, "preamp"?  The Prologue 5 is a  push-pull power amp.  It's nine pin dual triodes are phase-splitter and gain(driver) stage valves.
Give Kevin a call, at Upscale.  No one will be able to offer better advice, regarding which will yield the most, and what tubes will best provide your favorite aural flavor.  (https://www.upscaleaudio.com/pages/contact-us)