WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
Yes, it's always fun to build a "rulebreaker" that sounds good but shouldn't. See my Class B thread that nobody cared to answer.
But there are often nagging idiosynchrosies one hears that are then revealed later on through thorough testing.