Can’t buy output tubes anywhere except from manufacturers at high prices.

I asked TELEFUNKEN Elektroakustik and they told me the tubes were made in partnership with JJ Factory of Slovakia.

I thought it was always common knowledge the "Telefunken Black Label" tubes were just JJ’s. Always look at the shape of the glass dome (especially on EL34, for example) -- only JJ’s have that goofy, awkward rounded dome shape.

We at eastendhifi I have KR Audio tubes in stock. We carry the KT88’s, the 300B tubes, as well as a 300 BXLS from KR Audio.  Yes, they are certainly not inexpensive, but they will sound better than anything out there, other than maybe Western electric, and they will last longer than the JJ tubes. you can check out what we have available at eastendhifi.com.

Having just entered the fray again with amplifiers that use very fragile tubes I have noted that the best prices are available only at the origin of the tubes. A Winged C 6AS7 here is $45.00 but from Russia is $15.00. Shipping for 40 tubes was 20 dollars! Check out TubeTerra. The same holds true for 6NS7s but the very best NOS tubes are only available from Russia for a whopping $8.00 per tube. I had to do a lot of research to find these tubes. You do not have to be gouged by American vendors. Get your tubes where they get them from.