Don, I don't get into the negative cycle loading much, its more of a protection device, to prevent splatter and so on. I think anything that changes the input waveform is distortion. I do run some compression, to compensate for moving around while talking.
The mike preamp does limit the peaks (one of those berringer things), but not much. Brett N2DTS > > >I limit my quick peaks in the mike preamp, and include negative > >cycle loading in all RF decks, but don't push things much. > > I don't use negative cycle loading or ultramodulation, but I do take > advantage of the natural asymmetry of the human voice. Mine > tends to run > about 135% positive when I limit the negative to 100%. The > ratio would be > more like 2:1 if I clipped off a few excessive negative > peaks. I usually run > about 640 watts DC input to the final. Considering the > losses in the PA > tank circuit, the matching network at the transmitter output, > the feedline > between the shack and the tower site, and the remote antenna > tuner at the > base of the tower, I'd be surprised if I'm getting as much > as 400 watts > carrier output to the antenna. When I talk, the modulatior > plate meters > just barely wiggle beyond static plate current, unless I > whistle or make a > sustained tone. With a sinewave signal from a generator I > can make each > modulator tube draw up to 400 ma! The only "processing" I use is the > Universal Audio/Urei Model BL-40 Modulimiter (the only > solid-state device in > the station except for the homebrew cw keyer). > > > >There are people on the band who run/can run excessive positive > >modulation, but you need a special detector I guess, because > they sound > >bad in my shack when they do. > > I just make sure there is no flat-topping on positive peaks > or bright spots > on the baseline in the negative direction. I once tried > ultramodulation, > but I think I gained much more distortion than talk power. > Most reports > indicated the audio was no louder, but had a scratchy sound. > The most > effective thing I ever tried for "talk power" was high level > symmetrical > speech clipping back in the 60's, but it added audible > distortion, and I > went through about half a dozen modulation transformers in > about as many > months, ranging in ratings from 500 to 2000 watts. After I > abandoned the > high level clipping, I havn't lost a single modulation > transformer since. > > Don K4KYV >
