Mullard EL34 that sounds best

Oh it's fine, we are just talking tubes.

Tube Depot has a stock of SEDs EL34, I bought my quad from them. One was defective, only held for 700 hours.

Then there is a seller from the UK on ebay who sells, as he says, original Svetlana winged 'C' s EL34. They look a little different. I'll try one of those later too.

I have always read that caution should be used when buying vintage used or theoretically NOS from Ebay.  My own personal experience was buying some RCA black glass VT231s from some guy in France, and two of them quit working not too terribly long after I took delivery, and I took the rest of them out and put them in storage after that. 

Yeah, but he has an excellent and substantial feedback, and each tube is under $100, so I'll give it a chance. One tube to begin with.

Just can't spend that much on new Mullards from Tube Depot, though they have some other Mullards for $300 each new.

Besides, they only have a few tubes in stock, so it is not a long term solution at all.

Have you thought about trying Rays tubes?  I have not but if you believe the reviewers they sound very good.  Around $850 per quad for their reserve quality and $300 for the select quality and they’re warranted for 12 mo.

Never heard of them. "Sound very good" is not good enough for me. Either I will stay with SED Winged, that are alright, or will want vintage Mullards.