4699 el6 tube Philips power tubes quad metal base 1950's pre el34 amplifier rare

4 tubes 4699 Philips tested with tube tester funke w19s  

Test results = 35mA for all 4 tubes  (reference good at 19mA)

code tube 1 = FK5 56J engraved on metal base 35mA

code tube 2 = FK5 57E engraved on metal base 35mA

code tube 3 = FK5 58J engraved on metal base 35mA

code tube 4 = FK5 56E engraved on metal base 35mA

all 4 tubes full disc silver getter 

full getter 

all metal base 

old production 1950's 

box 153