[turretslug]

The Chapman S6BS here applies full AGC to the mixer (ECH81 heptode) on MW, then progressively pots it down as the bandswitch goes higher in frequency, presumably in the interest of frequency stability- whilst the whole point of the triode-hexode was to reduce frequency -pulling at HF in consumer sets, the change in effective inter-electrode capacitance with signal grid bias can still have an effect. (It's not shown on the circuit diagram, where the coil-pack and switching is shown as a block, but it's obvious on inspection). This set does have the luxury of 1x RF, 2x IF and AGC amplifier stages, though.