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RCA EL84 Date Code Confusion

rotobadger

rotobadger

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Just bought some vintage RCA EL84 (don’t have them yet). I’m going to swap out the JJs that are in my Gillespie Magnavox 8601.

The tubes are listed as from 1963 and use the the following format “xx-xx”. In this case 63-22.

But I looked up date codes and found that RCA used two letter codes for that era as well.

Does anyone know if there is a difference in quality or sound between the two code format variations?

Got them for a reasonable price and am looking forward to trying these on my SE amp.
 
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Just a quick bump as I haven’t gotten any replies. It’s not a huge issue but I’m curious. Seems there’s very little info on these tubes.

Thanks!
 
1963, week 22. The military insisted on "open" date codes and other customers may have as well. RCA had all sorts of stamps (equipment makers and other tube brands) and would probably label them any way you wanted for a quantity order.
 
Tom Bavis said:
1963, week 22. The military insisted on "open" date codes and other customers may have as well. RCA had all sorts of stamps (equipment makers and other tube brands) and would probably label them any way you wanted for a quantity order.
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Thanks for the reply! So, other than the labeling difference, the tubes were identical to their “commercial” versions?
 
I wouldn't assume that they're military or other US government purchase just from the date code. If a certain customer wanted a quantity labeled that way, RCA may have labeled a whole production lot (less work than doing them separately).

There were tight specs for tubes used in military equipment, but the government also bought lots of spares for commercial equipment which were normal production.
 
Tom Bavis said:
I wouldn't assume that they're military or other US government purchase just from the date code. If a certain customer wanted a quantity labeled that way, RCA may have labeled a whole production lot (less work than doing them separately).

There were tight specs for tubes used in military equipment, but the government also bought lots of spares for commercial equipment which were normal production.
Click to expand...
That makes sense. Thanks much!
 
Just an update: Got the 1963 RCA tubes in my Gillespie 8601 and biased. They are light years better than the new JJ EL84s!

Very happy with these tubes!
 
Tom Bavis said:
If a certain customer wanted a quantity labeled that way, RCA may have labeled a whole production lot (less work than doing them separately).
Click to expand...

Yes in those days, auto radio, lab, and communication equipment manufacturer's often required the YEAR-WEEK designation be stamped on the tubes. Even if the specific in-house company had already stamped their own codes.
 
rotobadger said:
Just an update: Got the 1963 RCA tubes in my Gillespie 8601 and biased. They are light years better than the new JJ EL84s!

Very happy with these tubes!
Click to expand...

Very few newly made output tubes can match a truly NOS from the classic US and European manufacturers. The key is finding a high-testing, quiet NOS tube. :)

Good luck with those RCAs. Should last a long time, provided that the unit has a good PSU and the tubes are biased correctly.
 
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