I've noticed in online bidding, the prices of 2A3 tubes, some are low & others are expensive. What makes the difference, brand name our is it just luck??

NOS 2A3s are sought by audiophiles. They are still being made in Russia, but even those are pricey. There are some differences among NOS 2A3s - for example, TungSol (and perhaps others) made them with two separate plates.

For antique radios, it doesn't make a difference. Go with tested, used tubes.

THere is a cult following among audiophiles for the benefits of triodes in lower powered amplifiers driving very efficient speakers for a most pleasing listening result.

2A3,type 45, (2.5 v heaters) and the even rarer type 50 or the famous type 10 (7.5 volt heaters on these pups!) are all in the same family.

I'd add that more afforable "modern" triodes, such as the 6CK4, and the boss end of some compactrons like the 6GF7 could emulate the performance, or hooking up a 6v6 in triode mode, but I'll probably be ridiculed harshley for mentioning it.

That;s OK< I have thichk skin

Now, the tubes vary from tired old run of the mill pulls from old radios and organs, to pristene NOS finds, single plate (uncommon,) dual plates, black plates, and so on. Engraved, springs, getters, ad nauseum hype the listings. As far as I know, Shuguang (China) still produces some of these and they are are very nice indeed.

One thing more, the relatively low output impedence (2500 ohms) for the 2A3 makes high quality output matching transformers particularly valuable as well.

I've noticed in online bidding, the prices of 2A3 tubes, some are low & others are expensive. What makes the difference, brand name our is it just luck??
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