| As far as I can see, I think that C1, next to the 6A8 tube (in the schematic) in the antenna circuit, is one of the two gangs of your tuning condenser, and C1, connected to the oscillator circuit under the 6A8 tube (in the schematic), are the two gangs of your tuning condenser. They are both connected to the chassis, which means that the frame of your tuning condenser is connected to the chassis. Tuning condensers, whether connected directly to the chassis or not, are commonly isolated on rubber bushings. This dampens out vibration that might otherwise cause frequency modulation feedback. This happens when the speaker plays a really loud passage and then vibrates the condenser plates. This changes the frequency that is tuned in, and causes a fluctuation in the radio circuits, which then passes on to the speaker again, and it howls like a microphone placed too close to the speaker. This problem isn't common, but manufacturers often isolated the condenser anyway. New rubber bushings can be found at your hardware store. Purchase many. This way some can be placed in the original holes. Then others can be cut in half and used as shims, if necessary, for putting the condenser back to its original height. Have fun with tubes. They are a lot of fun, and are easy to understand. I have heard, though, that people who start off with solid state technology, have trouble with tubes sometimes. Tubes are amazing devices, capable of far more than most people to-day realize. They are more sensitive than any other device of similar nature (transistor), and are faster responding than any other similar device. Unfortunately they aren't extremely stable (emission dies off with age), and they take up a lot of space. Though they could make computers faster than they are, the computers would take up huge buildings. Noone knows how to put a tube in a chip. They make radios sound really good, though, and will cook your food really fast. Your radio, though it will likely sound great, won't have the best sound, since it doesn't have push-pull output. Push-pull output is used on all fine radios, both modern and old. Most car stereos and high quality home stereos use push-pull output. Push-pull output, by nature, cancels a lot of distortion in audio. These distortions may either be in the form of clipped off audio waves or in the form of non-uniform frequency response. Push-pull is deep and rich, and of full range. A properly designed singe phase output can sound really nice, though. Thomas |
Will Hodges 
TonyC 