cgnman59 Feb 17, 2018 They are 6JN6 sweep tubes originally used in televisions. The amp was designed by Pete Millett. If you google him you'll find he is a well respected engineer and designer of headphone amps like the Apex Pinnacle.
They are 6JN6 sweep tubes originally used in televisions. The amp was designed by Pete Millett. If you google him you'll find he is a well respected engineer and designer of headphone amps like the Apex Pinnacle.