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Look up white paper's for the transistors inside the box first. MRF transistors, for instance, take far less input drive to achieve the rated power output compared to Toshiba's for instance. Start at 1/2 the rated input drive times the number of transistors and work up from there. A lot of MRF 70-100 wat transistors only need 4 watts to drive them but a 100w Toshiba might need 8-11w drive per device. MRF 50-60w devices often only need 1-3 watts per device.That said you can always go lower that as well. I do not drive amps very hard and they last me decades where some CB'er's drive the snot out of their amps and they last 3 months -12 months between repairs! So people can not agree on input drive and what is acceptable. It also depends on the input tune and the amount of padding.I am talking about modern amp designs in the above older amps will take far less input drive. A lot of the pre 1990's amps will be set up to accept 4 watts max because pre-export radio mania most CB's came from the factory with 65% modulation almost no swing and had the carrier set someplace between 2.75 and 3.25 watts. Most of them did not have trim pots to adjust the modulation either. This is also why power mic's came into to being! Also during this time clipping limiter's came into being.

<blockquote data-quote="Onelasttime" data-source="post: 608450" data-attributes="member: 21190"><p>Look up white paper&#039;s for the transistors inside the box first. MRF transistors, for instance, take far less input drive to achieve the rated power output compared to Toshiba&#039;s for instance. Start at 1/2 the rated input drive times the number of transistors and work up from there. A lot of MRF 70-100 wat transistors only need 4 watts to drive them but a 100w Toshiba might need 8-11w drive per device. MRF 50-60w devices often only need 1-3 watts per device.That said you can always go lower that as well. I do not drive amps very hard and they last me decades where some CB&#039;er&#039;s drive the snot out of their amps and they last 3 months -12 months between repairs! So people can not agree on input drive and what is acceptable. It also depends on the input tune and the amount of padding.I am talking about modern amp designs in the above older amps will take far less input drive. A lot of the pre 1990&#039;s amps will be set up to accept 4 watts max because pre-export radio mania most CB&#039;s came from the factory with 65% modulation almost no swing and had the carrier set someplace between 2.75 and 3.25 watts. Most of them did not have trim pots to adjust the modulation either. This is also why power mic&#039;s came into to being! Also during this time clipping limiter&#039;s came into being.</p></blockquote><p></p>

[QUOTE="Onelasttime, post: 608450, member: 21190"] Look up white paper's for the transistors inside the box first. MRF transistors, for instance, take far less input drive to achieve the rated power output compared to Toshiba's for instance. Start at 1/2 the rated input drive times the number of transistors and work up from there. A lot of MRF 70-100 wat transistors only need 4 watts to drive them but a 100w Toshiba might need 8-11w drive per device. MRF 50-60w devices often only need 1-3 watts per device.That said you can always go lower that as well. I do not drive amps very hard and they last me decades where some CB'er's drive the snot out of their amps and they last 3 months -12 months between repairs! So people can not agree on input drive and what is acceptable. It also depends on the input tune and the amount of padding.I am talking about modern amp designs in the above older amps will take far less input drive. A lot of the pre 1990's amps will be set up to accept 4 watts max because pre-export radio mania most CB's came from the factory with 65% modulation almost no swing and had the carrier set someplace between 2.75 and 3.25 watts. Most of them did not have trim pots to adjust the modulation either. This is also why power mic's came into to being! Also during this time clipping limiter's came into being. [/QUOTE]

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