What are we going to do about Tele 12AU7 prices

plenty of good sounding quiet au7’s out there still, at fairly reasonable prices ...

how various makes of tubes sound -- au7 ax7 6dj8 6sn7 and so on -- depends on the circuit/application, the condition of the tube

typically real german tele’s and siemens have a more spotlit character, at the expense of bass fullness - tungsrams from hungary are similar in character, they are excellent subs for tele-lovers

uk mullards are the opposite, more warmth and rolled off treble

dutch amperex/mazda are somewhere in the middle, perhaps a touch closer to the german character

american made old stock can vary as well, rca’s and philips ecg are generally well balanced, with nice extended highs, sylvania more treble centric, ge’s more rolled off

these are generalizations, specifics can vary considerably

Manufacturers also must consider consistency across their desired product run. For knstance, Audio Note may desire to produce 1,000 units of the XYZ integrated over a 10 year period. Maybe it has 4 XYZ tubes inside so they must stockpile or have access to 4,000 XYZ tubes plus, say, another 5,000 to cover warranties and retubes. So, when speccing the tube they need to spec where they can access 9-10,000 of this type type. Bespoke manufacturers like Shindo or Kondo might do limited runs of 20 pieces which reduces considerably the tube stockpile required. I would venture to guess that Schiit has no plan to produce anything remotely approching a small batch of anything. If they could sell 100,000 Freyas they would. Therefore, they will always spec their gear with the widest production of tube types to ensure product consistency. No serious manufacturer is going to spec a large batch product with an extremely limited tube as in rarer NOS varietals.

this that @ghasley describes is key to understand, and for even really excellent tube gear from an established maker, this provides an opportunity for us as singular users to experiment to find potentially better sounding tubes in our units - not that the process of doing so is without substantial effort or cost...