Well, the ol'fart is right if you understand a few things. Most of the amplifier circuits you commonly find are the same basic circuit. The differences are in the details, as in the selection of part's values which is determined by the requirements of the particular device doing the amplifying (tube/transistor), and what it happens to be amplifying. Different modes are constructed differently and can require different ways of being amplified.
In most cases, changing the values of one or two parts can mean a big difference on what's produced. That can be either good or bad depending on what the 'device' is and the mode it's handling. A particular tube/transistor can be expected to produce so much power (or amplification) in a certain time period before it get's too hot and destroys it's self. That time period isn't measured in days, but in microseconds. If those microseconds are few enough, the device will have time between those 'on' periods to cool off some. That's why tubes/transistors can be 'pushed' to some extent, as with SSB versus AM modes. They aren't 'on' as much as they are 'off', sort of. See where that's going?
There are practical limits! Those limits deal with how long that amplifying device is going to 'live' and act right. Exceed those limits and that device will either start acting 'not right' (or as expected), and will eventually have a shorter life span. The 'trick' is to select component values that result in the longest life span and result in acceptable performance. (All this is only dealing with 'practical' rather than 'electrical' limitations, such as cooling. There are electrical limits too.) While there's always a little 'skootch' room with things depending on how they are used and why, the manufacturers of those 'things' have all done enough testing that they can give you a very good idea of what's normal for a particular 'device'. Unless you want to do a lot of the 'already-done' te$ting, it's a very good idea to put some faith in what those manufacturers recommend. Those manufacturers will be very happy if you want to do that testing! It just means they are going to $ell you more of their product. (Think about that just for a minute. ALL reputable manufacturers do every kind of testing they can think of on their products. They want return customers, and so give good advice to that effect.)
The biggest 'trick' in all of this is knowing how and why a particular device works as it does. What will affect it, and how. That knowledge is commonly called 'stuff'. And that's why them that got their 'stuff' together do good stuff. Right?
- 'Doc
thanks wayne
