Mullard EL-34's from the 1950's

[jeverhart]

While cleaning out the attic, we came across a box belonging to my late Father-in-law. He was a TV, radio repairman in the 1950's and 60's. We came across 2 boxes labeled "Mullard" and EL-34. They both have metal bases. I tested for continuity on posts 2 and 7 and both were good. The serial numbers on one is "SY1" and "56J". The other is "SYO" and "57A". Are these tubes valuable?

 

[mtemur]

While cleaning out the attic, we came across a box belonging to my late Father-in-law. He was a TV, radio repairman in the 1950's and 60's. We came across 2 boxes labeled "Mullard" and EL-34. They both have metal bases. I tested for continuity on posts 2 and 7 and both were good. The serial numbers on one is "SY1" and "56J". The other is "SYO" and "57A". Are these tubes valuable?

They are Philips metal base EL34 tubes made in Holland. Those are the most valuable EL34 tubes which is hard to get in NOS. I have a quad of them but I prefer Mullard XF1 or XF2 Blackburns.