Driver Tubes 6922

I agree with jss...   in my Mid Monos a 6922 that may not be really quiet in a Preamp will work fine in the driver pos.   

I use JJ in there now and I think its the input tube that make the most difference in these.   

I have some early 60's RCA 12ax7 at the input and these amps have never sounded better.     When I bought them at about a year old the former owner also really liked RCA because there were early RCA 12ax7 in there.   

I bought a tube tester last year and it was an eye opener.   Most tubes I got from trusted dealers were as advertised but I had a number of tubes that were duds. 

Mismatched triodes, weak,  also had a bad 5r4gy (shorted) that would have damaged my new 300b amp.    That tester paid for itself that day.  

My reasoning to buy it was because I was starting to play with antique tubes like 300b and 274b / 5r4gy  types .    That amp also uses e180f  which is only available as NOS or used.    Fortunately that tube and it's variants are easy to find NOS but I want peace of mind before using ANY tube.    That said, even brand new tubes get tested before going in any of my gear 

Unfortunately I have also received tubesI thought were used ....  not from Brent but another well respected dealer.   

The truth is that a lot of "NOS" tubes are "pulls" , tubes that were lightly used but still test stronger than new.  In the 50's and 60's tons of test equipment and medical instruments had tubes.   When these instruments were decommissioned those tubes were pulled and went into someone's stash.   

I repair medical equipment and still occasionally come across really old power supplies that are tube rectified and filtered.  It was common practice to pull tubes out on a lot of stuff before trashing it 

You could have and probably did receive NOS from Brent but another problem is that after 50 or 60 years the silkscreen flaked off.   Sometimes just touching the print will wear / wipe it away.   

The only way to know you are getting a good tube is to test it.   I ultimately ended up buying a tube tester.   I have a buddy who does clean outs and occasionally he will drop off some tubes.    The last tubes he gave me that I believed to be NOS was a pair of early 60's RCA 6v6.   The boxes were rough but the tubes tested strong , better than min.    Were they used briefly and put back in a box ?   No one will ever know...   

Personally for the 6922 I would just buy a pair of Gold Lion or JJ that is matched and tested for noise.   Its only a few bucks more but you know you are getting new, strong tubes.  

I'm sure Brent will take care of you.   I have had a few tubes from him and they were always as described.  

Those testers are 60 plus years old so I'm not expecting true accuracy.   I want to test for shorts first and foremost.    That's what will damage your gear.  

Tomcy6, you are dead on.  No one tracked the tubes that were in those caddies.   Repairmen had tons of tubes on hand.   It was common practice for a tech to replace all tubes ,  that way much less chance of a return call.   What happened to the tubes that were pulled?  They went back in someones caddy and the bad tube was tossed.  

My tester is within 50 microhmos of a 6L6 and 12ax7 that were tested on an Amplitrex so that's good enough for me.  

I didn't buy it just for that.  I test all parameters .   I was lucky and found d 9ne that looks like it was in a museum.  It was serviced a few years ago by the previous owner.   

I'm sure Andy is a good guy and reputable,  but if I bought tubes from him I would test them as well.   As mentioned earlier my tester is fairly accurate enough to verify I'm not getting screwed