If power is not a issue, the 2a3(2-3 watts) will be far more superior than the 300B(8 watts). The 300B are very good in mid and high only, the low is not very good(less control). The 2a3 will beat the 300B in mid, high and low(with more punch and control). I currently using 2a3 tubes(my triode amp can use both kinds of tube) and I have no desire to buy a pair of 300B.
