I have an Atwater Kent 30, made in 1926 which is two years before a power supply for 120 VAC was offered on any set.
This AK set is a single-knob TRF and will not get much daytime reception without a 120 foot outdoor antenna. But, that was almost the best you could get then. Not a house rocker at all, volume and sensitivity were both limited by the B battery's 90 volts, type 01 output tube and horn speaker.
The 1928-29 early power supply sets from Philco used a triode tube for every stage but upped B+ by using a transformer to increase DC to 150-250 volts. Model 87 from Philco used type 26 triodes in the RF section but featured increased audio power thanks to type 45, a popular push-pull output tube - specifically for audio.
It was not until the type 24 tubes were used, which included a screen grid, that AM performance took a huge leap forward. By October 1929, Philco model 95 was advertised as "screen grid plus" yet still sold less expensive triode models for a while. Philco can be credited with much of this early development but Zenith was going to catch up by the end of the 30s, when built-in antennas were developed (not sure who to credit there) also known as the "wave magnet".
If anyone has the need for an amazing old radio like these at a give-away price, then I strongly suggest a trip to Kutztown, PA next month or September 16-17. There are so freakin' many radios there, some get left behind if not given away. The resources to repair them are almost endless, now with the internet. Take the plunge!!!
http://www.tuberadioland.com/philco95_main.html
BTW - The 26 tube was used in the neutrodyne model 87, which is vague reference to old technology.