This is a suitable replacement for any 12AU7 tube type. Various brands available.
Holland Made Philips SQ E180F 6688 tubes. Triple Mica gold pin construction! 6688=E180F 10,000 hour 9 pin broadband pentode. Recommended for: Nobsound- here is a link to a video made by one of our customers after he received his matched pair for his Nobsound headphone amp: https://www.facebook.com/scott.lowell.5/videos/10208623852628597/ Supratek Chenin Cortese preamp Yamamoto 06-3 2010 $29.99 per tube