Just a walkthru look see of 2 dual 3-500z legal limit amplifiers. Many people, especially on Facebook, say a Watt is a watt is a watt. If an amp, tube, or part is rated for a certain wattage, then that's it. You can't squeeze water out of a rock. In almost every realm, except CB and Ham radio, this is true. In almost every other rating, the ratings are for continuous duty, period. Electrical AC power and ratings for your house, continuous duty. Power for commercial buildings and equipment, continuous duty. TV sets, stereos, air conditioners, cars, generators, commercial broadcast radio stations........continious duty.
Now enter the world of Amateur and CB radio. No CB or Ham keeps the Mic keyed down for years, months, days, or even hours at a time. With that in mind, manufacturers now can design and make a device that is up to the task of intermittent non continuous keydown and most do just that. Almost all power parts have a rating curve with continuous duty on one end and very low intermittent or quick pulse being on the other end. For CB and Ham, it would sit somewhere around the middle of the curve. Most know that SSB is easier on an amp than AM and AM is easier on an amp than CW or FM. SSB has a low duty cycle, AM mediuim, and FM is full. Plus you factor in the intermittent keydown time of CB transmissions. As said earlier, CB is not keyed down for hours or days etc. If you do, that's on you. Anyway, Hams came up with a rating/curve for normal Ham operation and keydown. ICAS standing for Intermittent Commercial and Amateur Service. Different devices, like tubes vs transformers would have different curves and fall on different places on the curve. However, in general, you can safely get around I.5x using the ICAS rating of a device than using the CCS rating of the device. Hence the tale of 2 amps in the video. Heathkit SB-220 is an ICAS rated device and for SSB at that. The original power transformer for the Heathkit SB-220 is rated at II7I volts and .7 amps CCS which would be about 800 watts CCS. Using my I.5X calculation that would still be only around I200 watts ICAS. Again, the Heathkit SB-220 is an SSB ICAS rated amp. People hit it hard and usually sooner than later, blow it up. On the other hand, some manufacturers made full CCS amps. Alpha used to go to swaps and literally key down their amp into a dummy load at full carrier power for the duration of the swap. They would literally put a Brick on the footswitch. For swaps like Dayton Hamvention, this would be for 3 days. Again CCS, they could key down 24/7/365. Some commercial Broadcast radio stations used CCS amps like Alpha and Henry for drivers for their big amps.

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