BAL470

BAL 470 is not the designation of these tubes.
They were manufactured or selected for the former Luftwaffe (Air Force of the Armed Services). BAL stands for "Bauaufsicht Luft" or "Supervised Construction - Air" and/or "Accepted work for Air Force". The number designates the reference to a particular inspection station which usually examined a large number of different tubes.
More information about these examination stamps is given in this link. If we know more about this particular examination number you will find a forum article below.

We try to show here all different tubes with this BAL-number. Each picture legend should give information about the actual tube type plus all other markings on that particular tube. We would like to show only one picture for each tube designation if all other markings are the same (incl. date).

Colección personal de