MOSFETs vs. Pills

[420Snowman]

You know that's right Silver Eagle!! Mosfets are the new pills....


Snowman

[rich33]

ya, if there were plans to build a MOSFET amp i would jump on that. Probly would be some what simpliar then a regular pill amp.

Original post was 2009
Oh what 4 years can bring. You can pick and choose what MOSFET amp you want now.

I would quit the hobby before running a mosfet amp. 11 meter Mosfet amps and radios have to be babied or they will go poof.

[halfwatt959]

I have a palomar 250FET. It has two IRF7530 s in it. With 15wdrive it only puts out 90w@ 13.8v. Now up the v to 15 you get 150ish. Up it yet again to 18v [normaly use will never see] 200w. My opinion? They used the wrong trans. 6 IRF520 s at 30 cents each should give 150-175w at 13.8v unless I need new batteries in my calculator. Be glad to pull the skirts off the 250FET if any one wants a look. This thread has me wanting to xperment with the 520 s. I can get 100 IRF520 s for $30 + shiping. Can afford quite a few mistakes at that price.Will keep posted 73s Karl

[yamaha]

I use a 1 driving 4 mosfet amp for ssb operation and could not be more happy with its performance. It does a solid 400 watts pep. I have smoked a few Fets but they are cheap to replace and that could have been a 2879, 2290, or a 1446 anyways. Everything can and will smoke sometime,, But you live and you learn,,, I admit that on "AM" I still use a standard "pill style" amp to get my name called, But on side band the fets shine crystal clear.. Here Is a shot of the guts. Don't be afraid, Just think people now are building single FET devices pushing kilowatts. This is by no means new technology but just is now showing up in the mainstream CB amp market thanks to the current transistor prices and availability..

[silvereagle1]

I like the MOSFET amps. My kl503 puts out solid clean sound on AM and SSB. just show them a little respect and they'll live a long healthy life. They won't take abuse that is true but why would anyone want to abuse them anyway it all comes down to personal preference. Some like FETS and some like pills doesn't make either of them bad just different styles. The FETs are the newer style so some don't understand their limitations because they are used to using high drive pills so a few get smoked along the way and boom I hate fets! No big deal because they are cheaper to replace. you just have to get used to using and understanding them. Once you learn how they work and their limitations they are really nice amps.

Kl503 still going strong after a year of service. I've had it paired with a 99v2 a 980 and the grant 2. 99v2 is a duel final radio and it performs very well with 1.5 watt DK input with a 15 watt swing. if it blows tomorrow I can't complain about the service it has given me for the past twelve months.

[Deleted User 14541]

There are real RF rated mosfets out there but they aren't cheap. For a solid state amp I prefer a bipolar transistor over the cheap mosfets that are commonly used. A lot of things get deemed as junk because they can't be ran at 2.5 times the rating like the Toshiba 2879 could be.

[Bluerunner]

AC to DC equivalency is based on the fact that a sine wave (AC mains power) is two half circles. Geometry involving a circle easily converts the average sine wave AC to a relevant DC unit. Special equipment is needed to read a non-sinusoidal waveform as a DC equivalent.

That is what gets all the free energy guys in trouble. They read the power output of their devices with equipment that is designed for measuring RMS sine wave power. Their secret generator junk is putting out all kindza crazy aberrant wave forms (kinda like voice modulation) that can't be read properly with typical meters. They get a lame electrical engineer (who slept through this part of the class) to swear the readings are accurate and proceed to bilk the investors.

Everybody knows that it takes fairy dust and powdered unicorn horn to get free energy and big oil has hunted down and shot all the unicorns and has thousands of employees chanting "I don't believe in no fairies" all day every day killing off the few fairies left.

The specialty electronic meters needed to accurately read aberrant wave forms are very expensive and need technical knowledge to use correctly.

However, if we go back to the basics...... All everyone used to use back in the early days of radio was a hot element watt meter. The amount current going through a resistance element will always produce the same amount of heat and needle reading regardless of the frequency or waveform. Very cheap, accurate and no special skills or training are required to use it.

[Deleted User 14541]

Everybody knows that it takes fairy dust and powdered unicorn horn to get free energy and big oil has hunted down and shot all the unicorns and has thousands of employees chanting "I don't believe in no fairies" all day every day killing off the few fairies left.

Makes me think of a guy that found a way to increase his fuel mileage by pulling isopropyl alcohol into a vacuum line (old carbureted engine). He did well in science fair that year but in reality all he did was create a vacuum leak that leaned out the fuel mixture. Months later the repair bill for the burned valves ate up all the cash he saved on fuel...and then some.

[Lost Ram]

My 6 pill 2879 red dot makes an honest 500-ish watts, driven by my 2970N2.

[Foliant]

I can get 100 IRF520 s for $30 + shiping. Can afford quite a few mistakes at that price.Will keep posted 73s Karl

Curious about it.

Have tried to build some but never got the trick right...

[Moee]

Everyone quit playing with the 520? Seems to be a lot of bang for the buck.

[-=PEAKABOO=-]

Everyone quit playing with the 520? Seems to be a lot of bang for the buck.

Not a RF device and is low gain. Much much better options they just cost more.

[Lost Ram]

Has anyone been playing with the BLF188XRS. I think this is my next toy to build seeing they have boards you can buy pretty cheap now days.

[Crusher]

I have used the blf188xr with very good results. I built everything from scratch. No pre fab stuff. Very easy to do if you understand circuitry

[Lost Ram]

My biggest dilemma is wrapping my head around the bandpass filters I need for the different bands. Making a mono band is no big deal. I am trying to educate myself now on the theory in this but also I think I lack the test equipment to be sure I have the bandpass filters correct. Well, perhaps my first one will be Mono banded until I can make myself smarter LOL.

[Crusher]

Just make sure you track the bias.

[Moee]

Everyone quit playing with the 520? Seems to be a lot of bang for the buck.

Not a RF device and is low gain. Much much better options they just cost more.

I've seen a single 520 do over 100 watts seen it many of times. I no not all 520 can. But some seem to have. A local builder has been building with them for years. Just figured by now more people would have been using them. Yeah there not a RF device I get that. But they work well on 11 meter. There the 6lq6 of mosfets. Lol. One Dollar each. That's a lot to be gained?..

[nk14zp]

GO TUBES!!! LOL

All this talk of transistors and I'm still using tubes. lol

[TrblShooter]

GO TUBES!!! LOL

All this talk of transistors and I'm still using tubes. lol

I am still using tubes as well...

[jon6667]

i saw a 16 mosfet wizard amp on ebay. the guy is claiming he can get 2.500 watts out of it.
i find it hard to believe this. how about you. think its possible. to see that kind of wattage out of a mosfet amp.

[jon6667]

tubs man tubes are cool and they warm up the room. and they glow in the dark. i have a few mosfet amps i built years and years ago. never used them. i never had no use for a amp.