Tubes for my Mac's 275....NOS or just used?

Used are used and NOS is Old stock but un used....There are plenty of good NOS tubes around..You just need to know the House sound of each type you need..Each one sounds just a bit different so you should buy from an expert tube supplier...Don't buy Ebay junk,you may be sorry if you do.......

NOS is supposed to mean New Old Stock, new meaning zero hours (brand new).

There are tubes that fit this description but not as many as advertised. Many sold as NOS are in fact used tubes. That being said, used tubes that test new are typically low hours, test equipment pulls or test spares. Many of my tubes are used and bought at great prices.

If you want NOS and willing to pay top dollar, Andy Bauman at Vintage can supply them, just be prepared for a long wait. He is meticulous.

As for Ebay, a good many of my hundreds of tubes came from Ebay and generally I've been treated well. Unfortunately you have to know tubes before you can shop Ebay successfully as there are about 20 levels of quality there every day.

Agree w/Thorman -- if you do not have a tube tester -- stay away from those who sell vintage plates and dolls in addition to tubes (just using an example & have nothing against vintage plates nor dolls).