linear cookbook

[fodendaf]

I doubt anyone has built one of these amps without reading mauldroppers. The only reason I posted it here is because the link was broken there for some time and maybe still is for all I know. But we all know with the demise of the 2sc2879 these plans are almost obsolete now. There are more competitively priced and reliable parts available per watt which is what most manufacturers are using. I guess we both take it for granted that whoever uses these knows what they're doing, does their research and not to build anything larger than a 4 pill due to mismatches from a lack of test equipment usage blowing transistors.

 

[Crusher]

LOL, your assuming a lot. A lot of guys I know tried to copy and didn't look nearly as neat or as well soldered or capacitor leads that were way too long. The DEI will work with those amps. But some tweaking will be needed as the devices are not electrically the same. Also the DEI flange seems to be just a hair bigger. That's all I'm saying.

 

[cbkidd1]

I know this is a old post. My computer crashed and I lost my copy of the plans so I downloaded the amp plans from the link that fodendaf posted above. There is only assembly instructions for building a 4 pill amp. Would anyone know where I could find the rest of the assembly instructions or another complete set of amp plans? 73,

 

[fodendaf]

I know this is a old post. My computer crashed and I lost my copy of the plans so I downloaded the amp plans from the link that fodendaf posted above. There is only assembly instructions for building a 4 pill amp. Would anyone know where I could find the rest of the assembly instructions or another complete set of amp plans? 73,

I don't have any more information than the original zip but I reuploaded it for you.
https://archive.org/download/AMPPLANS/AMPPLANS.zip

 

[cbkidd1]

Good Evening Fodendaf,
I wanted to thank you for taking time out to repost it for me. The only thing that was missing from my copy was the assembly instructions for each amp what a shame lol. 73,

 

[fodendaf]

They're all more or less the same to build. I lost everything myself a month back when I formatted the wrong disk. They were identical model numbers so I had no easy way to tell them apart. The important stuff was saved online though.

 

[cbkidd1]

I wonder why each amp did not have it's own manual?

 

[fodendaf]

I suspect it is because the bigger amplifiers were never intended to be built without someone skilled at balancing the stages. They're just there as a rough guide to follow rather than hunting down pics online or buying amps to clone. Some mentioned there were various problems with the design. bob85 said the 4 pill was doable by the amateur but any larger would self-destruct.

 

[Shadetree Mechanic]

Amp plans bump. Is there an easy way to tune for HG transistors?

 

[2315 Robert]

Amp plans bump. Is there an easy way to tune for HG transistors?

Shadetree I just did a txt star dx 500v whiteline and reflect was good. However on 2 transistor models I have had to tune. I hope you get your a answer. Handy Andy was very helpful to me.

 

[2315 Robert]

Shadetree also wanted to mention I just have one variable capacitor and many silver micas. Really wish I was better at it.

 

[unit_399]

2315 Robert -

If you are really serious about building linear ampliifers, I suggest that you read the following Motorola Engineering Bulletins and Application Notes.
EB-63
EB-27A
AN-593
AN-721
AN-749
These papers describe the design and construction of the RF linear amplifiers that are the basis for most of the transistor linear amps used today. A lot of pretty heavy math, but worth a look. All are available online. Good luck.

- 399

 

[2315 Robert]

Jefe 399 most appreciated. I'm reading Malvino. As the prophets have said "it's a long way to the top of you want to rock n roll" Merry Christmas.

 

[kopcicle]

...also
AN-762
AN-779
Virtually anything by Helge O Granberg...

 

[unit_399]

This 1993 Motorola Engineering Bulletin (written by Helge Granberg) shows how to use 4 MRF150 RF power FETs to get 600 watts PEP. Complete kit (parts, instructions, assembly hints, Circuit board, plans, etc., available from a supplier mentioned in the writeup. About $300 bucks including the FETs.. Requires a 50vdc @ 20 amps supply.

If you're looking to build a linear, ANYTHING designed by Granberg is the way to go.

EB104: Get 600 Watts RF from Four Power FETs

- 399