In connecting up the set, be sure to solder connections directly to the wire of the antenna coil, and the secondary of the regenaformer. This is the reason it is marked optional. It will be noticed that the rheostats are connected in an unusual way, which facilitates the use of the voltmeter, so that it reads the maximum voltage across the filament of all tubes. This voltage is controlled by rheostat No. 2. More will be said later, concerning the setting of these rheostats.
Many people believe that separate rheostats for the detector tube help bring in distant stations.
In the case of DV2, DV3, UV201A, UV99, WD12, and WD11, it seems to make no difference in volume whether the detector has a separate control or not. In fact, it is better to run the detector tube at rated voltage on the filament as cutting down this voltage tends to distort signals. This is why the detector and two audio tubes are connected to the same rheostat. The ideal arrangement of tubes would be a DV3, or UV199 in the first socket with UV201A tubes in the other three. The 25 ohm fixed resistance shown takes care of the small tubes filament voltage so that if rheostat No.