Why are people paying these stupid tube prices?

The Shunguang plant in China is not up and running yet. As a state-owned enterprise the government seized the property after a fire at the facility. I don't know at what stage the new factory is in, but we won't see their tubes soon.

And with New Sensor, the Russian government stopped tubes from being exported, causing a supply chain interruption. Now that the factory is running at full capacity, their brands are available again. But the scuttlebutt is the US and Canada have added a 35% tariff to Russian imports.

In the US, WE has produced some tubes other than 300b's and are beta-testing them in a select group of audiophile's systems. There are very good reviews of their 6SN7. 

Tube Depot has KT150's for 144.95.  They are Tung Sol, so not sure if they are good enough for your amp.

Back in the day, we used 6550's, which were pretty good tubes, and KT88's as well.  Tube Depot as those as well.

Cheers!

TubeDepot isn’t presently selling the TS KT150 - look at the specific page

I may be wrong but I don't think Psvane or Linlai make KT150s

Been loving SS since 1965! I’m still enamored by those SS devices. Tube heads are boobheads. 
 

Tubes: A fool’s errand!