While your source may be excellent your amplifier is ill-suited to lots of things given it's high output impedance. Maybe the Utopia's are one of them? The quality of the tube you have in there isn't going to help with that, either.
And one person posting an opinion that isn't the direct mirror of yours is hardly the equivalent of anti-vaxer behavior. I don't know what axe you're trying to grind here but it's a huge bummer.