Well I've decided to do my first impressions of the vintage 5814A Sylvania's. And I think it's a very good sounding tube, great clarity with good balance, very nice mids & the bass extension is to my liking real good, plus nice & punchy but not as good as the wonderful sounding mullards.
I also noticed that they needed a little more volume then other tubes, and sound a little rolled off the top. Most of the time I give my amp a sufficient warm up time maybe 45 mins. or so I know that's not necessary but to my ears the amp sounds better the warmer it gets.
The reason I mention this is because these tubes didn't sound there best until about 2 hours of use, unlike all other tubes I own that seem to require less warm up time to reach their best, maybe it's just the pair I got or the fact that I've only spent a few hours with them.
So given the fact that these are half the cost of my favorites the mullards CV4003's they are a very good sounding tube, All in All they are worth a try i'm very pleased so far, I listen to mostly jazz, rock, and classical not sure that matters but some may wonder. I do like to give my new tubes about two weeks of use before I can really tell so I will add more later..