"I think their impedence curve does dip down to almost 3 ohms at one point."
That's probably a red flag with most any tube amp.
What is the amps rated output in 8, 4 and 2 ohms? If it does not double each time or come close, that could well account for the poor bass response.
That's probably a red flag with most any tube amp.
What is the amps rated output in 8, 4 and 2 ohms? If it does not double each time or come close, that could well account for the poor bass response.