Need amp suggestions for Hedlund Horns....

I pulled the full range single driver and it is an AER MK1 which from what I read is (can be) a great speaker with the right enclosure/baffle (for $2500/pair it better be). Again these AERs are in a Hedlund Horn (feel free to search Google pics) so no crossover.

As far as efficiency, not sure how to measure this or where to find as the AER website has no specs- any help would be appreciated. If I had to guess it would be in the 102db range.

So what is a good 300b design? What makes a "stiff" power supply? What’s a good output transformer? What specs should I look for? None of the suggested 300b manufacturers mentioned share their circuit design nor parts list. Is it better to have one built to match specs for the AER speaker?

Hello Ramoneo14,
If your speakers sensitivity is in the vicinity of 102 db thats very impressive. With a 300b SET amplifier you’d hardly ever get outside of the 1 watt range of power usage. In reality you’d be using only small fractions of 1 watt. Your amplifier is coasting at this power level and the distortion is nearly unmeasurably low as well. Most 300b SETs have 6 to 10 watts of power thus the headroom factor is considerable.

Bradf posted a list of of companies that offer high quality amplifiers with established reputations, also the Allnic and Border Patrol amplifiers mentioned earlier. A few more quality brands are Thoress, Ocellia,Wavelength, Sophia Electric, Audion , Concert Fidelity, there are more. Certainly there are differences between various brands brands and their models.

However what this list has in common is very good quality design, part quality (P. Supplies and output transformer) solid track records. Definitely lots of choices and it takes some time to sort thorough them and gain some degree of familiarity. The 300b SET amplifier niche is very alive and plentiful.
Charles,

From what I could find online looks like your driver is over 100db efficiency and 16 ohms impedance so you should be able to drive it with virtually any good single ended amp even down to 1 watt or so. A stiff power supply means the power supply is robust and typically way over spec for the amp in question.

Since my speakers are VERY efficient, is the 300b still the "best" tube to use?  Is there anything "better" at 1 watt or so?  I want that warm bloom that I heard once, music just coming alive like I've never heard it.  300b vs 45 vs others?

16 ohms speaker impedance is ideal (generally speaking this means easier load for the amplifier to drive). I agree with Jond,  on paper this speaker "should " be an excellent match with the vast majority of SET amplifiers.