I think the Heerlen, Holland tubes are generally thought of as being the midrange champs and the D getters as being a little more laid back or richer. The small O getters are a little more lively.
Of course when you try these in your system you may wonder how in the hell people came up with those descriptions as they sound nothing like that in your system.
Of course when you try these in your system you may wonder how in the hell people came up with those descriptions as they sound nothing like that in your system.