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

Viva Tubes has them. The prices are up but,  the price of everything is up now.. 

Viva Tubes has them. The prices are up but,  the price of everything is up now.. 

They've been out of KT120 and Gold Lion KT88 for a while now. And their supplies may be dwindling on remaining Russian KT88, EH KT90, and KT150. Mullard KT88 are still available for now (up to matched octets), and are excellent. Better get those while you can, if you're in need. I bought a couple octets for my VAC amps.

I just sold two pairs of GL KT88 matched quads on USAM - both quads sold within one day of listing.  I no longer have any amps that run them.  I apparently didn't ask for enough!  So yes, clearly the demand is real and the supply is low.  

@mulveling Have you heard the Mullard KT88 that Viva Tubes is selling, and if so do you feel they are as good as the Gold Lions?

@weebeesdad

Yes, I have the Viva Mullard KT88 in my 200iQ’s right now. I’ve previously (this year) had both Gold Lion KT88 (stock from VAC) and Tung-Sol KT120 in these same amps. I haven’t directly compared the two, and I’m not going to say they sound exactly the same, but the KT88’s sound much more alike than different. I really like both! They are of equivalent quality. The KT120 sound more different, but also excellent -- they’re a bit meatier through parts of the midrange and bass. Incidentally, the KT150 were awful in these amps -- the bass was powerful and fun but overpowered the music. 

Anyways, I’m a fan of all 3 of these tubes! In my main system I have a pair of VAC Master 300 amps, with the stock KT88 Gold Lions. There are SIXTEEN of them, so I’m not gonna change them until I have to 😅