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6x2sc2879 amp

B

bigred222

Key Up City Radio
Aug 28, 2006
1,155
53
58
34
Stamford, CT
www.cbjunk.com
since my texas star is cooked i figured id build a class c 6x2sc2879 amp with the case if i can fit it in there, cut the board up and see how it goes. any ideas or input. does anyone have the pdf from the old amp plans that powerplate used to sell?

SHOCKWAVE WHERE ARE YOU
 

Hello Red. This has been done before so I can tell you it does fit although it's probably not the best approach. You have to gut the 667 since the boards and switches are not ideal for the application. At that point you're just using the heatsink and case. Probably better to fix the bad output that burned your combiner and sell the working amp to get closer to what you want.

I won't discourage you from experimenting with building your own. If you get it working in class C you can always add some bias later if you want to clean up the SSB signal. When you say you want 6 of these transistors I'm assuming you want them all in one stage and are not wanting two as a driver.

That will require the use of a 3 port splitter and combiner that will tie all 3 banks together in phase. Although this type of combiner or splitter is very easy to make by wrapping your own windings around standard cores, you'll find much less published information on the 3 port designs than you will for the more common 2 port devices.
 
this would be a lot of fun to do but i just spent the past half hour pricing out all the parts from what i got from the parts list i found on the web and for a 1x4 it comes to about 350$ worth of parts including almost everything NOT including shipping and not including the immense amount of solder i would need plus various other little hiccups and stuff i would surely probably come across needing to buy. So... im not sure whether i really want to do this or not but when i have the cash for all the parts ill give the 1x4 a shot or just build a 2 pill base amp and learn how to build a very crude basic unregulated 15 volt supply and put it in a nice case and paint it red and all that other happy crap, if anyone has any input on the subject, it would be most appreciated. or if anyone has any parts the would like to donate to the cause feel free lol :love:
222 Connecticut MOTOR CAR gone......
 
psycho said:
Since this will be your first amp build a straight 6 pill is a bad idea.
Click to expand...

Yea for a new amp build a simple 2 pill 2290 or 2879 would be a better choice. Heck for the money just buy one. Leave the brain surgery to a doctor.
 
If you do build an amp, think about picking up a switching supply. You get can get a nice mean well brand switching supply that will power it nicely for about $60-70. Ready to go. V should go up to about 15v. If you did an unregulated, the transformer alone would cost that plus you need caps and rectifiers and small heatsink for rectifiers. Will cost a lot more. Best bang for the buck. I think the 400 is what I use, will power. 2 x 2290 or 2879 nicely.
 
Matt, trust me on this one. If you're planning on using this in the house, I wouldn't. Crazy as it sounds you're still better off buying some old sweep tube amp like a Palomar 90A or 300A off eBay. If a transistor amp is the slightest bit unstable, it will be the dirtiest thing you ever keyed up from your house. Even if it doesn't oscillate, it won't be nearly as clean as the amps I suggested when properly driven. You could save up a little more for a small Ameritron but it will need more drive power.

If you really want to learn how to build something solid state yourself, start with the basic circuits first. Things like tuned circuits and how to use them in matching. Then there are filters. Made from simple capacitors and coils wired together that will clean up harmonics. Can't forget about bias circuits. Even simple ones will improve things noticeably and can be just a few parts added.

You should learn the proper "support circuitry" around the RF amp before you build the amp and bypass the support circuitry first. Then you're just coping what just about everyone else does and that's not learning. Plenty of self proclaimed Tech's use that approach.
 
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