Newbee,
In general I wouldn't say that this is an imagination but closer to truth but not to all tubes and tube components. In general I can state that higher bias current almost identically to transistors bring tubes to more stable and distortionless responce with proper tonal balance as well.
After all in our case we're discussing a device with output transformer that introduces one more variable of load complexity of primary circuit matching of which to the output tubes defines the largest effect compared to the setup of the bias current in tubes.
In general I wouldn't say that this is an imagination but closer to truth but not to all tubes and tube components. In general I can state that higher bias current almost identically to transistors bring tubes to more stable and distortionless responce with proper tonal balance as well.
After all in our case we're discussing a device with output transformer that introduces one more variable of load complexity of primary circuit matching of which to the output tubes defines the largest effect compared to the setup of the bias current in tubes.