Can anyone generalize that the 45's are more authoritative, with more solid tighter bass than the 300B or 2A3?
or is it brand dependent?
In a power amp position or in a DAC?
I'm going to infer that since you posted on this forum, you are asking about such tubes as used in the LIO DHT PRE.
I would not
generalize by saying that 45's have a tighter bass than the 300B or 2A3. It really depends
on the make/model of the tube. And if they are used tubes, their age will come into play as well (and how they
were treated, the circuit they were used in, etc).
Also - the circuit topology that the tube is used in will most certainly come into play, as well as the parts of that circuit.
Even the load of the following stage will have some influence over the overall sound (e.g. driving a power amp with a 10k input impedance vs. one with a 100k input impedance). Everything
matters - even the type of matter matters, and in general, maybe it is best to leave the generalizations to the generals?
(sorry - that was really bad but I couldn't resist!)