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The first link is dead, the second one that I posted is just fine, checked it just now....
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These look like the PSF tech plans made by PowerPlate. I bought most of these 2-3 years ago. They are alright plans. I had bought them back then to see how much difference there was between the Comp stuff and this. There are differences. That is all I am telling. Hmmm..... Thinking I should copyright my bias board before I start selling it. Thanks for the tip. LOL
Do whatever you can to protect your work, quite a few scum-bags were making money on these plans, and still are over on the gaybay. your shit will no doubt be copied regardless what you do, but a little protection is better then none. Personally I would rather not see someones work whored out like these are, but the alternative that some POS makes cash from them is worse, then they brag about it on the forums... :thumbdown:
Technically speaking the fellow over in Aniwa (used to live about 20 miles from him) was pretty silly not to copy-write them, but you have to be a real butt-munch to charge fellow forum members money...
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BOOTY MONSTER
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i think powerplate also sold a ab bias kit or plans for their amps . im guessing yours is different . i cant recall who , but someone here built a class C amp with switchable AB bias board installed . i wonder how many ways a AB bias circuit can be added to a class C amp .
i remember a few years ago at CBRF i was told as class C amps gett hotter they move into class B biasing . essentally saying heat will replace a bias circuit , LMAO . they they didnt like it when i asked if one was stuck in a oven what temp would be needed to take it to class AB biasing .
Bake or Broil ????
i remember a few years ago at CBRF i was told as class C amps gett hotter they move into class B biasing . essentally saying heat will replace a bias circuit , LMAO . they they didnt like it when i asked if one was stuck in a oven what temp would be needed to take it to class AB biasing .
Bake or Broil ????
The class B bias board that they had was VERY basic. Just a few resistors and diodes. It was class B as long as you didn't key. (that should be a hint)
You're absolutely 100% correct, with no regulation and under load the rig would get as hot as the surface of the sun and soon go poof.
Even with regulated baising, you still need some way to track thermals. Also on a side note, even a amp that has regulated biasing, should not be biased. Once the transistor is biased were it is continually conducting, any increase to voltage on collector will cause it to conduct harder. Several tens of mA in fact. Just some findings I discovered while testing on the bench.
I have always been a tube builder. Never did much with transistors for amplifiers.
Thought that one day I would build a all band transistor amp. There is a lot more to it than I thought.
So to start with I built one fron the plans here. It turned out quite well. But it is nasty on the spectrum. I sarted off with a dead mirage amplifier case and installed a board in it.
I did not like the ugly construction of the keying circuit so I built mine up on a perf board.
Every part but the board came form the junk box in the shop. I made most of the broad band transformers myself.
I dont think it turned out to bad for my first solid state amp. It was very educational.
After I gain some time on some other projects I am plan to build a solid state all band amplifier.
Thought that one day I would build a all band transistor amp. There is a lot more to it than I thought.
So to start with I built one fron the plans here. It turned out quite well. But it is nasty on the spectrum. I sarted off with a dead mirage amplifier case and installed a board in it.
I did not like the ugly construction of the keying circuit so I built mine up on a perf board.
Every part but the board came form the junk box in the shop. I made most of the broad band transformers myself.
I dont think it turned out to bad for my first solid state amp. It was very educational.
After I gain some time on some other projects I am plan to build a solid state all band amplifier.
This one is single bandat the moment. needs lot more circuits to cover all band. A whole lot of band switching net work to put in the top cover.
This one is tuned for 29 mhz. Works well on FM. I have ben studing more on how to filter these things. Has not happened yet.
Hence the thermal tracking via diodes and pass transistor into voltage regulator circuit regulates the amount of bias applied to the base of the transistor thus holding it at the desired bias(.560ish of a volt).
The 2sc2879 that I've biased usually draw around 250ma idle current and should remain very near that if your regulation scheme is any good.