I'm looking at a pair of 6V6's, and there is a date code shown on them. I was wandering if anyone could date them. Also was curious of the quality of GM tubes. I never knew automotive manufactures made there own line of tubes.. Unless they were re-branded..

I don't remember seeing a alpha type date code on any OEM GM tubes I have, are those replacement stock??? Dunno exactly when, probably early/mid 50's tubes began to have Delco brand...

As far as who made them, GM never made the first tube were all purchased from the major mfgr's, likely has a code on it, 188-GE, 274-RCA, 312-Syl, etc... NU(247) supplied many tubes as well...

Tom

Idk if they are replacements or not.. They are on the bay. Ive been eyeballin' them for a while now. That is what the seller is calling the date code. I kinda figured they were 1950's, but figured i'd see if anyone here would know better then me. I was planning on having them as a set of spares or possibly my primary set bc they match. Then i'll put away my non matching ones for spares. The seller wants 25.00 OBO plus a little shipping for the pair,which i think is an excellent price.

A0 could be a KenRad code from 1950, if they were still using their older system by that time. Jim Cross would have a good handle on this.

I have a GM coke bottle 6V6 with code E8 and I assume it may be prewar, but I thought it was an RCA. At least I compared construction details and it looks identical to an RCA internally. Saving it for a Champ clone project.

Whether they are KenRad or RCA, they would still be good quality tubes. I'm probably going to make an offer on then in the next few days.

These were made by RCA.

"AO" = May 1958.

Volume 1, #2 of the Tube Collectors Association Magazine, "Tube Collector", has an exhaustive listing of date code of tubes made by RCA. I keep my copy at my desk. Back issues are sold by complete year only at www.tubecollectors.org

Jim Cross

Thanks Jim.