04/12/2013 09:21 In many commercial high power tube amps the ceramic caps in the tune and load circuits are small value, paralleled up to create a bigger value. Is this because smaller values drift l
It is about reducing drift, but it isn't quite that "smaller values drift less". The main reason for using smaller values is to share out the RF current between several capacitors. As the heat losse
The most extreme use of the technique I've seen was some 50 years ago in a 50kW (output)long wave (50kHz region) tx at Marconi, where something like 50 or 60 ceramic capacitors of about 68pF and 5kVA
Also, another reason is that two small ceramic HV caps are usually much cheaper than one high current ceramic cap as used in the past. Today, it's very difficult for amplifier's manufacturers to find
The issue is the dielectric on low frequency, a doorknob capacitor can stand 3 amps on 3.5MHz. but only 1 amp or less on 1.8 MHz. Because of the high loss on 1.8 MHz the capacitor get hot, than if it