@wolf_garcia
By the way, there are MANY sources for great 6SN7GTBs including Viva Tubes, and my preferred are GE NOS...plentiful and great sounding.
Just two years ago I bought multiple matched quads of really good NOS Sylvania Black Long Plate plate 3-hole 6SN7GTB tubes for $200-225 a quad. Sure, there are sources, including Viva below, 3x the price now days. Sure, GEs are available for notably less cost.
------------------------------------------------
Tests NOS Matched Quad (4x) Sylvania 6SN7GT Black 3 Rivet T Bad Boy Plate Tubes
Sylvania
$617.35