• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

EL34 identification

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
What are these EL34 tubes bought in the early 1970s? Some state United & others Amperex. Plates are with two grid access rectangle hole spacing that match up to only the older RFT. No codes exist on the glass. States 'Made in USA' (thats not likely).

Amperex, Telefunken, Japan, all Russian & all Chinese I could find doing a Google search have different rectangle hole spacing. These tubes have a top & side ring type getter. The top of glass is fairly flat & smooth.
 

Attachments

  • tn_100_3456.jpg
    tn_100_3456.jpg
    61.9 KB · Views: 241
Amperex....
I would "guess" that those are German EL34 tubes based on internal geometry.... The outfit that bought them and relabeled them must have left the "MADE IN USA" on the screening process... Might have been too much of a pain to remove it and possibly they could have been under the gun to get thier products out quickly to satisfy a contract/bid.... UNITED ELECTRON sounds like a relabel.... EL34 Tubes that don't measure up for AUDIO applications work great for pass elements in voltage regulators....

Chris
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.