Time for a new experiment: EL30. This is a tube I was not able to find more information about. It seems it was produced by Philips France and usually found with metal base branded RT or black base (maybe also metal?) like some Visseaux tube. But if you look about this tube, well, almost nowhere nothing. This raised a flag in my mind: I'll have to try it but first check it to see if it behaves normally on the tester. Lack of info is a risk.
So here we have a quad of these:
A detailed photo:
And then some measurements. Being bought quite cheap, I had no expectation and because I was not able to find any info about it also my willing to spend was limited. But I found a quad for 20 EUR and then my curiosity led me to buy these. Now, from the 4 pieces one is DOA (even if it heats, no light is seen on the heater and emission is 0 so I presume it's dead). Then measurements are quite ok for the rest, measured as I found on Radiomuseum (Va=250V, Vg2=250V, Vg1=-4.5V and Ik=18mA), so 86%, 89% and 104%. Decent values. From the 3 pieces which work, I have selected the ones being closer and made a pair. On the amp these are around -5.2V grid for 180V/4mA.
Now soundwise, well these sound an idea dull at 4mA and most probably they sound better at around 18mA as advertised but well, here's a funny thing. I have to put these at 18-20mA and 200V in the output for around -2.5V and my negative grid bias there does not go so "up", at minimum I have around -3.5V. LOL So I cannot test these in output, what a shame.
In short, I'm forced to try these only on input on top of some 6V6 -> 6J5 adapters (pinout is the same as 6V6). Regarding the specs, Radiomuseum speaks about 4.5W but on some sites I've seen totally different values. For example our "specially made for audiophiles" website Vint'Elec speaks about 25W
here but I doubt they are right. I think Radiomuseum has the right specs for these.
Now, I have to admit I do not like these on top of RT 4654, I tried them before with Philips 4689 and was no good pairing either. Sound an idea dull, lack sharpness and separation and make everything somehow unexciting. A tube nobody heard about which does not impress me. It was fun to try on output but well, I never thought I'll try a tube at -2.5V grid bias. So it's more in line with input tubes in my view at 4.5W. I doubt I'll listen to it too often but I will keep it around. One day it might shine.
That was EL30, moving forward.