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DEI Transistors

Shockwave

Sr. Member
Sep 19, 2009
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This is going to be good because I've already popped the caps off of all the familiar RF transistors and was surprised to see how much larger the surface area of the silicon wafer is inside the Toshiba than ANY other transistor in its class. I'd be shocked if the DEI even got close. Keep in mind small changes here can make a big difference in what the device can really handle.
 

KD2GOE

W9WDX Amateur Radio Club Member
May 30, 2013
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This is going to be good because I've already popped the caps off of all the familiar RF transistors and was surprised to see how much larger the surface area of the silicon wafer is inside the Toshiba than ANY other transistor in its class. I'd be shocked if the DEI even got close. Keep in mind small changes here can make a big difference in what the device can really handle.

 

psycho

Running a special on our rooms!
Aug 25, 2006
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I would be more than happy to. The only thing is, I'll sacrifice the DEI as stated earlier, after it goes "pop" I will also pop literally the case off and take a few snap shots. The only thing is, I really don't want to sacrifice a Toshiba, so if someone has a bad Toshiba 2sc2879 around maybe they could take a photo to compare it to. I would if I had a stash, but the bad ones got thrown away a while ago, and my new ones, well... I really don't want to sacrifice one.


Any channel 6 regular who runs a mobile should have a whole shoe box full of dead soldiers.
 

Shockwave

Sr. Member
Sep 19, 2009
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Or even the guys who run unregulated on a base. Unregulated supplies are going to be a thing of the past.

I have to admit that is ridiculous. How can you even begin to build a linear amplifier knowing that the supply voltage is going to be bouncing all over the place between word peaks and thereby preventing any possibility of linear operation? Nothing wrong with being cheap so long as the circuit continues to resemble its name "linear". Gotta love that AC hum that still gets by no matter how many microfarads of electrolytic you add too. Regulation is the key to removing all AC ripple.
 
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RadioGuy772

Active Member
Dec 30, 2013
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Not to get off topic, but it all goes back to the part that I "said" earlier, about how they will leave out things that are typical desirable (or in this case, considered necessary) as long as the end user does not know any better, and as long as it makes a watt meter move.

If by chance, the end user starts to ask questions, then they will revert to some nonsense, about how they are the only ones doing things this way because they have the "unfair advantage" and it's a top secret design from years of scientific research and almost use social engineering tactics on the customers to make them actually believe that they are part of some top secret society of superior products, when in fact, it's just all BS.

It may be off topic, and might sound like I'm analyzing the psychological nature of all of this too much, but I have seen it time and time again.
 

Shockwave

Sr. Member
Sep 19, 2009
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BINGO! If you want to claim that you're giving your customers some unfair advantage, then actually do it. Not expecting any miracles here either considering the wheel does not need to be reinvented but simply applied.

Stop resisting the inevitable and admit all bipolar and power supply MOSFET's are obsolete or not appropriate for the application. Concede that you will have to apply new technology that has already been all figured out for you. Now just learn it and combine the cutting edge technology that already exists.

How many more years are we going to have to wait before someone figures out how easy it is to use real 50 volt MOSFET's and still run them from a 12 volt source in the vehicle? No MotorMaul or external mods are needed either. The audio market has been using 50 volts and more in their amps for decades without placing a single battery in series with another.

It's called the DC to DC converter and has been around in high power applications for many years. Today's high efficiency light weight switching versions make this easier and more economical than ever before.
 
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RadioGuy772

Active Member
Dec 30, 2013
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Excellent, *EXCELLENT* point. It's called, switch the DC on and off, step it up, and wow... you have the required VCC. We used to do this years ago for displays using nothing more than an OP amp as an oscillator at an AF frequency, and use that as the basis for our crude switching supply. Also, what's up with one modulated stage feeding another, then feeding another and another? If you are going that far, why not just amplify the carrier or exciter, apply AF at the last stage, and create class D AM? Efficient, and it's simple using modern devices. A lot of the broadcast industry is doing it, and has been for years.

Now, for other modes, where linear stages are needed throughout you of course couldn't do this, but once again, the problem of low impedance, stable, bias supplies for BJTs is gone with modern devices, and is so much more simple. Simple voltage dividers work here.

Anyway, before we get knocked for getting off topic, I wanted to chime in after seeing your last post because to me, it just made perfect sense.
 

Shockwave

Sr. Member
Sep 19, 2009
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why not just amplify the carrier or exciter, apply AF at the last stage, and create class D AM? Efficient, and it's simple using modern devices. A lot of the broadcast industry is doing it, and has been for years.

Now what would we do with all that extra power not being used to warm the passenger compartment of the car? Before you know it you'll want to modulate the class D RF stage with a class H PWM and take all the heat out of running some heat. :eek:
 
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GnG8d

Well-Known Member
Jun 28, 2010
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I have to admit that is ridiculous. How can you even begin to build a linear amplifier knowing that the supply voltage is going to be bouncing all over the place between word peaks and thereby preventing any possibility of linear operation? Nothing wrong with being cheap so long as the circuit continues to resemble its name "linear". Gotta love that AC hum that still gets by no matter how many microfarads of electrolytic you add too. Regulation is the key to removing all AC ripple.

I don't think those guys really care about linearity or AC hum tbh.
 
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shadygrady

Member
Jan 15, 2012
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do not weary

if you have the new dei an need less volts than what you have i can get you a power supply from 12.6 volts - 13.8 vdc real reasonable price you can run it all day with out blowing it up grady 9314325588
 

psycho

Running a special on our rooms!
Aug 25, 2006
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I have to admit that is ridiculous. How can you even begin to build a linear amplifier knowing that the supply voltage is going to be bouncing all over the place between word peaks and thereby preventing any possibility of linear operation? Nothing wrong with being cheap so long as the circuit continues to resemble its name "linear". Gotta love that AC hum that still gets by no matter how many microfarads of electrolytic you add too. Regulation is the key to removing all AC ripple.


It's called unregulated at $500 vs $1500+ for regulated. As long as the amp is sized properly for the unregulated supply, shouldn't go higher than 14.5 volts.
 

Captain Kilowatt

Professional Amateur
Staff member
Apr 6, 2005
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It's called unregulated at $500 vs $1500+ for regulated. As long as the amp is sized properly for the unregulated supply, shouldn't go higher than 14.5 volts.


The problem is not with the voltage going too high. It is with the fact that it bounces all over the place. When this happens IMD goes up and linearity goes down. Also if the supply does not have the proper amount of filtering as more current is drawn the more AC ripple and hum that is produced. A regulated supply can get by with less filtering in some designs as a filter cap placed on the sense lead of the regulator effectively adds ten times that to the final filter value. Regulated supplies are of far better design than unregulated but you do pay for that difference.
 
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psycho

Running a special on our rooms!
Aug 25, 2006
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Chinese wheat gluten poisoning us.
Chinese pet foods and treats making our pets sick.
Chinese baby food making kids sick.
Chinese tires and valve stems putting drivers at risk.
Chinese drywall making people sick.
Chinese toys with lead based paint making our children sick.
Chinese dump raw sewage and industrial waste into the ocean.
Ect...ect....ect....ect.....


When are we going to learn......quit buying products from these scumbags.
 
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