In Oakland? Most of the homes in the region were built in the 1920s-1930s, though some were newer developments that were only about 10-30 years old.
Wooden construction is very common in America because wood is very common and hence cheap. In this particular region there's another reason for its use: it's right on top of a fault line, and wood-frame residential construction performs very well in an earthquake, while brick or unreinforced masonry tends to crumble.
Not that easy, AGC works both ways, if you disable it you need to provide a manual control to not blow your speaker or your ears or both. AGC controls the screen voltage of some tubes with a big factor of amplification. A typical remote cutoff pentode like a 6sk7 can change some 30-40 dB for stage. 70-80 dB AGC action is not rare.
> manual control to not blow your speaker or your ears or both.
Distinct from the volume knob?
It could be that rather than completely disabling AGC, it switches to milder compression.
Another idea is that while tuning, we can delay the volume recovery of AGC. In other words, the same fast compression attack, but very slow release, so that as the user tunes across the center of the band, they can still feel the volume swell.
A simple voltage divider could be introduced when AGC is turned off to attenuate the overall volume, so that the loudest blast is not that loud.
AGC is not compression, is a negative feedback loop that reduces gain to maintain a relatively stable output level. If you try to tune on a faint station near strong ones, the stronger carrier pumps the gain down, making tuning difficult. if you cut AGC the gain goes full up. You can cut AGC and reduce gain, but then you'll lack amplification to hear the weak stations.
If manual AGC and volume should be different controls depends on gain distribution across stages in the receiver. In superheterodyne AM receivers, most designs will need both to get best performance.
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