One pair 6SN7 are for the gain stage, the 2nd pair are the phase inverters.
Example; RCA L, R gain stage.
Raytheon L, R phase inversion (drivers for output tubes)
Example; RCA L, R gain stage.
Raytheon L, R phase inversion (drivers for output tubes)
VAC 70/70 mk3 tube rolling question
Typically; being certain to not use the exact same tube for the first two stages (same channel) of your power amp, will provide a better presentation. The most referred to 6SN7 comparison (http://www.dehavillandhifi.com/6sn7_vt.htm) mentions the practice of mixing things up, about three paragraphs from the bottom. More opinions on 6SN7s, here: https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/ No doubt, someone will mention the Melz tubes. You might want to refer to this thread, regarding their noise, reliability, etc:
https://forum.audiogon.com/discussions/shootout-of-nos-6sn7-tubes?highlight=6sn7%2Bshootout I guess they can be a nice tube, if you get lucky! |
Use matched set of Rca, matched set Raytheon. The input circuitry of the Renaissance Seventy/Seventy is derivative of the unique Williamson circuit, which provides pure, direct coupled, inherently balanced input amplification and phase splitting. Type 6SN7/5692 octal twin triodes do the honors. https://skyfiaudio.com/products/vac-valve-amplification-company-renaissance-seventy-seventy-70-70-du... |