Type 45 Tubes for stereo amplifiers

There are a couple of choices at Antique Electronic Supply: https://www.tubesandmore.com/search/node/45%20triode?categories%5B0%5D=Vacuum%20Tubes

I'm using 45's in my Supratek preamp. Sophia Electric has new 45's. I've settled on vintage National Unions as my favorite sounding. Off ebay. Dirt cheap compared to those linked. You'll get varying sound quality. As the previous responder said, you may have to buy 4 or 6 to get the perfect pair. But still cheaper than those new ones linked. 

I’m burning in a pair of EML 2A3 mesh tubes now for a monoblock pair I’m working on. Using them in a 20 year old Tektron TK2 2A3/50.

I’ve also got a pair of EML 300B tubes I’ve used for over a year.

Both sound awesome, the 2A3’s so far a little more “refined” but I’ve only got about 10 hours on them.

Can’t praise them highly enough. I think, for the price point, they’re one of the best deals going. And a 5 year warranty.

Someone mentioned SOPHIA tubes. I have a pair of 300b 2.5v Sophias mfd in 1972 that are still going strong. Great value for the money.

I have a Dennis Had Inspire "Fire Bottle" amp and LP3.1 preamp, and the "Fire Bottle uses 45's.  I love my Emission Labs 45's.

http://www.emissionlabs.com/datasheets/EML45.html

RCA  coke bottle style 34's sound very good and are reasonably priced.

I have used them in  my 45 amp..

Perfect Balance CLOSELY MATCHED PAIR RCA / ARISTOTLE 45 145/245/345 ST TUBE TV7 | eBay