Best EL34 reissue?

Yugo 6CA7 made in former Yugoslavia, but not sure which part: Serbia? Kroatia? MonteNegro?

I can't find it on Ebay or Amazon though...

Get some once you find. They used to be more frequent then now. They sound similar to fat bottle NOS Mullards if not better.

FWIW I have had nice results with both EH fat bottle 6ca7s and JJ 6ca7s in my pushpull 17 watt stereo amp. EH a touch warmer and the JJ's a bit more transparent but both nice tubes and super affordable.

A great alternative to consider is the reissue Genelex Gold Lion KT-77. With most amps it is a drop-in replacement for EL34s with the characteristics that people love about EL34s. Do a search on audioasylum.com for some informed opinions.

I've used mostly vintage EL34s over the last ten years in a couple of amps, original Teslas, RFT/Siemens and others, and the Gold Lion KT-77s are right up there with the best of them, with the big advantage of being able to source them tested and matched from great dealers like Jim McShane and knowing they're new production.

Of course, which tube you prefer depends on the rest of your system and whether you like your music sparkly, mellow or somewhere in between. Also depends on what you consider affordable, around $200 for a quad seems to be the entry point for really good sound in an EL34.