The Fender Deluxe was without it’s tweed covering but was otherwise intact. The Gibson GA-6 was in near mint condition. They were both in the shop for minor age-related repairs: faulty switches or plugs that cause noise.
While the circuits of the two amps are very similar, there are some differences.
The two volume pots and the tone pot are less than 500k, unlike a tweed Deluxe that uses 1M pots for volume and tone controls. Tone control caps in the GA-6 are the same values as the Deluxe.
So… How does this all translate to tonal differences? There were dramatic contrasts in the sound of the two amps. I used my big red bullet mic – which is extraordinarily hot, putting out 1 volt of current when I hit a loud passage.
Many thanks to Bruce Collins at Mission Amps for graciously allowing me to thrash two very valuable vintage amplifiers. Bruce is also the drummer in my blues band, Roadhouse Joe.