In fact one of the reasons CW can use power so much more efectively as compared to voice is because the amount of data is small you a dit and dash and it is monotone not a lot of data to a dit or a dash.Speech is very wasteful because of all the data in the voice. This is by design and this is the limiting factor for fiedelity not the amp's biasing not until you start talking about C and SSB. they focus on where most of the audible sound is in a humans voice. responce on most radio's and most radio mic's they do not focus on the low freq. By reducing the amount of data you can reduce the band width and focus your power where it counts the most. The more data you want to broadcast the more bandwidth you need. Just like CD's do not sound as good as well cared for vinyl the same thing happens with broadcasting your voice. The old tubed radio's with huge bandwidth hoging designs had the best sound but could not make it through type acceptance today with the FCC to save their life. I have yet to come across a modern radio that truly sounds great on air. You will find a decent mic and maybe a speech processor and call it good. Sooner latter you will get tired of all the time for such a megar gain and will run a radio mostly stock. You can spend a year playing around with mic elements and audio transformer's trying to get your sound right. You mic is a huge limiting factor the better the mic the better your chances of sounding good. If you have the time and a schematic for you radio you can really do a lot of little things to improve fidelity especially if your not hunting for every free watt you can get. I would try to find lower noise higher gain transistors and milspec anytime I could no matter if it was a transistor, diode or resistor etc.I would play around with component values to see how it would affect my audio trying to make my voice sound like my voice. I can tell you some of the things I did back when CB was popular and family friendly so some time ago.Depending on the design of the radio I would use two audio ic. Listen to that same record on a two channel amp built around some 2A3 tubes puting out what 1-3 watt's and the music sounds fantastic even though it is only coming out of 2 speakers not 6 counting a sub.!!! It is kind of like when you look at the spec sheet's of some stereo gear it looks fantastic then you listen to it and sure it is loud and clean but it just does not sound good. They have sought efficiency, power, compact design loaded with digital feature to the point that they simply do not sound life like at all. In general I think most amateur gear sounds dead as a door nail.Sure nice clean signal, plenty of power, and often they sound artificial and metallic. If you want fidelity you need to work on all the bottlenecks inside the radio. This is why I for a long time really liked amps with the MRF 455 now that those arenot in production I would favor the MRF421 over the 1446 or 2290 because in a well designed amp operated by someone that knows what their doing they will sound better then someone running a few more watts with say 2SC2789.Especialy on SSB. High wattage usually means Japanese transistors that are over biased. If you want fidelity do not over bias your transistors and chose units that have good inter-mod number's and lots of gain over the highest wattage. This is why we see so many AB or C type amplifiers in RF but no A's! Point is that nothing you do to that amp will improve the fidelity the bottle necks are many and scattered through out the radio's on both ends on the transmit side and the receive side and the reproduction of the sound. Then you have the audio circuit on the receive unit and the speaker. Then you have the physical band width allowed on that band that you can use not often ran into or talked about on AM but on SSB it is a limiting factor. The bandwidth you have at your disposal that the radio picks up, modulates and sends out from an audio stand point is very small.
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