Stock tubes bias 63 Vibroverb reisue

[elpico]

So to use your argument, installing 6l6gc tubes in the vibroverb R1 is effectively changing tube design compared to what the amp was designed for.

You may have no interest in the 1963 vibroverb, but the actual name of the model you *are* interested in is "63 Vibroverb Reissue". It's a copy of the 1963 Vibroverb, which was designed with 6L6GC.

There are many tube types similar enough to 6L6 to be plugged into circuits designed for 6L6. There are no changes to the circuit that make it "redesigned" for Sovtek tubes, they just used an available tube that works fine in 6L6 circuits. The biggest differences in the reissue were the modern PCB construction style and the decision to skip the tube rectifier, both changes for cost reasons.