Tube rolling can be fun and make you a little crazy at times. Both input and output tubes make a difference. For me the output tubes have a greater effect. But they are usually more expensive.
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What's especially interesting here is that the EL84s don't pass any signal, they are current sources for the 12BZ7s.
Ruby has rebranded several different EL34s. If yours are the Chinese/Sino they are surprisingly good, likewise the Tesla E34L with the rounded, domed, tops are just great.
Ruby also rebranded the Sovtek EL34G and that tube is not so good considering todays offerings. But the good news is that you have lots of choices in new EL34s and 6CA7s as well as the Russian 6P3S-E, which is a 6L6 type.