Where Did All The Transistors Go?

Yankee said:

My point is, the radio should not be made so it CAN push the output to a point that it fails, not out of the factory box. I have amps here with pills I have by accident, over volted, over driven and over modulated, still going strong. And I have a few here with FET's that failed the first time I sneezed with my finger on the dial. Just saying.

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It's called headroom. Example: A standard 100 watt HF amateur radio typically uses a pair of 2SC2879's in the output stage. These are run below their maximum ratings in order to provide a CLEAN signal with low IMD performance as opposed to a flat out balls to the wall Billy Bob tune up.The radios run cooler, cleaner on the air, and last a LOT longer without any problems. The big problem today is everybody thinks they know better than the manufacturer and wants to be the loudest guy on the block. Start cranking a radio to it's limits and beyond and you are asking for troubles. I know of people that have cranked the ALC in their Kenwoods and Yaesus because a pair of 2SC2879's should be abole to make an easy 250 watts. Right? Some in CB land like to think they can get 400 watts pep out of a pair. Start doing that and watch for burnt out power supplies, burnt traces on the circuit boards and crappy sound quality and fried finals. All this because someone decided they would make a radio do what they thought it should be able to do. It's sort of like a car. drive it sensible and it will last a long time. Drive it like you stole it all the time and it will give you troubles long before it should. Should they make cars that cannot exceed the speed limit or not get up to 60 Mph in anything less than 30 seconds? It's not the manufacturers fault but rather the fault of the owner/operator for wanting to treat/mistreat his equipment by pushing it to operator constantly at what should only be the upper end of it's capabilities. Some amateur gear has had MOSFETS for at least a decade or more. A lot of commercial gear has had MOSFETS for 20 years or more and almost never have a failure. then again these are being operated as the manufacturer speced and not as the owner/operator wanted too. One problem with todays MOSFETS in CB radios is that most of the MOSFETS are switching types that just happen to work at 27 MHz and are not true RF type devices. This is a fault of the equipment manufacturer in not selecting a device suitable for the purpose and operating it outside the manufacturer's spec.(meaning the manufacturer of the device itself).

Yankee said:

How about we all start calling the shop before buying this junk, ask some questions, namely "do you sell any radio with transistor finals?" and then when the inevitable answer comes, ask why not? Then say you are going to shop around some more, maybe wait till one comes out. The best way to get a manufacturer to start offering a product the customer wants instead of one they have to force on them is to push back on the companies selling the junk and let them send the message back up the line. You know already that the company that leads the charge back to the transitor is going to get the most sales. *Don`t do it*

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Screw transistors. I want TUBE finals in all my radio gear and amps and I am far from being alone. Lets call the dealers and ask if they have any new radios with tube finals. When the inevitable answer comes ask why not. Put the pressure on the manufacturers to start giving people what they want and not what they will be given.

I have as much chance of getting what I want as you do and it is for the same reason. Old tech.

MOSFETS are not the problem. Proper use of them is.MOSFETS have been used in commercial applications since the very early 80's without an issue.

Then stop buying CB and export " junk" completely. GOOD MOSFETS are being used in ham gear and have no issues. You will NEVER see a return to bipolar transistors regardless of how much you scream. The technology is old. Bipolar RF transistors are not being made much anymore. That will not change. Just like tubes RF bipolar transistors are destined to go the way of the Dodo bird because there are GOOD alternatives out there. The CB world is less than a drop in a bucket when it comes to demand for solidstate devices and as such they will follow the demand and not create the demand. Most of these MOSFET radios function quite fine as long as they are left alone and out of the hands of the peakers and tuners.

Fet`s or MOSFET devices are here to stay, there are well designed devices out there now that will do more, provide better protection, and run cleaner at higher output than any 2879/2290/any other bi-polar ever dreamed of doing.
Captain has summed it up very well.
And I seriously doubt that the Manufactures are going to stop using them in any of the new radios any time soon.
It is about $$ spent in the factory for parts, and unfortunately the guy at company headquarters in the accounts department has more pull than the "engineers" that designed the pa section in the radio.

( accounting department )That transistor costs us $6 each in 1000 quantities, are getting hard to find and we can get these fets for 64 cents each in 1000 quantities, do you know how much money that can save us? We are still going to sell the radios for the same price and raise our profit margins.
(engineer ) But it will not work properly as a drop in replacement.
( accounting) So what, you can make a few changes in small parts that cost a few cents and make them work, we are not buying the high dollar transistors anymore, deal with it.

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73
Jeff

Yankee said:

I already have. But I wonder why you say The technology is old, like there is something wrong with a well made good sounding radio that works great and lasts for 40 years and is maintainable by anyone who can change a tube?

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I say the tech is old because it IS old. Don't get me wrong,I LIKE tubes. I like my Heath DX-60B AM transmitter and HR-10 receiver. All tubes. I LOVE my Kenwood TS-820S with it's tube finals. Any amplifier I ever have for HF will be tubes most likely a pair of 3-500Z's I like tubes. Tubes require a minimum of two different voltages and some require at least three. That adds to the cost and complexity of the power supplies and the over all cost of the equipment. Tubes age over time and require periodic tweaks in certain circuits to maintain them properly. This adds to maintenance costs unless you know what you are doing yourself. Dangerous voltages inside leads to a liability issue in today's litigious society where nobody is willing to take responsibility for their own actions anymore and would jump at the chance to sue a manufacturer for not making it impossible to contact the high voltage line while attempting to do something they are not qualified to do in the first place and despite all the warnings present regarding the high voltage. Most people today can't use a TV remote properly so that rules out that option. Lastly nobody is making quality RF tubes any more. Sure RF Parts etc has RF tubes ut they all come plant in China and are not as good as the old ORIGINAL Taylor brand or General Electric, or Westinghouse, Sylvania, RCA or Eimac brands.

And yet, there is an expanding return to tube powered amplifiers for those who have the money. You can buy them, brand new, every day, on Amizon. So it seems not everyone is buying the pap about FET's being better.

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Not sure what amps you are referring too. Audio amps? Sure the audiofools will always crave tube amps and most have more money than brains when it comes to spending money for audifool related items. Some of it just defies all logic or reason but it's their money. Tube amps do have a certain softness to them compared to solid state (regardless of FET or bipolar) due to the switching times and this results in less harshness. Most of this is measured rather than heard however. If it sounds like I am bashing the audiofools it's because I am. I spent 22 years in commercial radio broadcasting engineering department and know good audio when I hear. It was my job for that time to ensure we had the best fidelity and lowest distortion we could. we don't have that silly over compressed loudness wars that seems so prevalent on the US broadcast bands. During that time I met many self proclaimed audiophiles that IMHO were nothing more than audiofools with lots of money and a tendency to overstate their abilities. In a blind test almost all could not tell the difference between a solidstate Altec Lansing amp and an older Yamaha tube amp that I had in the shop. :laugh: