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tubes vs. transistors

B

buckwhite

Guest
this may have been covered before but i will ask again. a friend of mine keeps telling me that a tube amp will outperform a transistor amp if both are showing the same amount of power. how could we test this theory short of putting a huge low pass filter on the transistor amp? if my amp is doing 1500avg. how much should i expect to loose putting a filter on it? i know some of the power my amp is showing me is harmonics, but how much? his argument is since you can tune a tube amp within a certain frequency range then the power output of the tube amp is more "actual power" vs. harmonics... i see where he is coming from but until he brought it up i really never thought about it too much... L8ter


CDX-316

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I think it really depends on which particular amps are being compared. There are very clean transistor designs, and there are very dirty tube designs. It also would depend on the input signal in either case.

Is there something inherent about tubes that make them actually sound better than transistors? I don't know, but I've been told that there is, at least in audio amplification. Something to do with harmonics and the human ear, but I can't remember exactly. Whether that holds true for RF amplification, I don't know that either. Maybe one of the heavy hitters on the board can add something here, lol
 
OK, I saw this post a while back, but didn't get time to respond.

Watts are Watts. If a tube amp is putting out 1500 watts and a transistor amp is doing 1500 watts, then they will perform the same, all things being equal. Tube amps have a reputation for being "cleaner" than transistor amps, i.e. less harmonics. However, it is perfectly within the capability for a transistor amp to be "clean", as well. I think you'll find that if you take a tube and a transistor amp that each meet FCC specs for harmonics and are rated for the same power output and compare on a Spectrum analyzer and scope, you'll find very similar power output levels on frequency.
 
Moleculo is dead on the money. It's just physics. Watts is Watts. If the spectrum analyzer can't tell the difference, neither can a radio (and operator) at the other end.

But to me, that's the smallest part of the picture. Why? Because the folks who are most interested in this question are probably the folks LEAST likely to operate their stuff the way Moleculo describes.

The big differences between tubes and transistors at RF have to do with ABUSE. That's right. When you ABUSE a tube amplifier, it will magnify the differences between how IT responds and the way a solid-state amplifier responds.

If somebody starts spouting off about how superior tubes are, or how superior transistors are, I gotta figure this guy drives the holy dog snot out of his stuff. And that's where the big differences arise. Tubes distort DIFFERENTLY than transistors do. Overdrive an amplifier an it will distort. Guarantee.

If you don't believe that tubes and transistors distort differently, ask any (electric) guitarist. That's one group who knows the difference. And nearly ALL of them overdrive THEIR amplifiers. Some of the time, anyway.

73
 
For the purpose of discussion on the Radio message board, I will concede that electrically (W= E x I) watts are watts however, I do not see or hear WWKY or WTMT using "Fatboy", "Snowcap" or, "Dave-Made" boxes lashed together broadcasting for commerce.

Nor, do I see or hear any "Big-guns" using "pills" to achieve the multiple thousands of watts that they use on the "BOWL"

"Joe Toshiba" will never be qualified to carry the tool bags of Mr Eitel or Mr. McCormick.....


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Most commercial broadcast stations use transistor based amplifiers today. Of course they're not built by CB guys.....
 
Most commercial broadcast stations use transistor based amplifiers today. Of course they're not built by CB or Ham guys.....
 
Moleculo said:
Most commercial broadcast stations use transistor based amplifiers today. Of course they're not built by CB or Ham guys.....
Click to expand...

Show me a link to some Mole; we have a "Clear-Channel" station (WLW-700 AM) broadcasting 50,000 watts 24-7, they are using tubes.

More importantly, the FAA mandates that all tranmitting equipment used for Air Traffic Control be tube type because if it's immunity to "EMD Pulse" damage versus transistors that can be taken out with a sneeze (almost).


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Paws,

The Big One definitely has the tube audio. I wish I was alive when they ran the 500,000 watt transmitter I saw pics of that monster. All AM Radio BroadCast Stations that cover any kind of regional coverage are tube. Mole may be right on FM Broadcasters using Transistors.
 
nomadradio said:
Moleculo is dead on the money. It's just physics. Watts is Watts. If the spectrum analyzer can't tell the difference, neither can a radio (and operator) at the other end.

But to me, that's the smallest part of the picture. Why? Because the folks who are most interested in this question are probably the folks LEAST likely to operate their stuff the way Moleculo describes.

The big differences between tubes and transistors at RF have to do with ABUSE. That's right. When you ABUSE a tube amplifier, it will magnify the differences between how IT responds and the way a solid-state amplifier responds.

If somebody starts spouting off about how superior tubes are, or how superior transistors are, I gotta figure this guy drives the holy dog snot out of his stuff. And that's where the big differences arise. Tubes distort DIFFERENTLY than transistors do. Overdrive an amplifier an it will distort. Guarantee.

If you don't believe that tubes and transistors distort differently, ask any (electric) guitarist. That's one group who knows the difference. And nearly ALL of them overdrive THEIR amplifiers. Some of the time, anyway.

73
Click to expand...
Im new at this but I agree watts is watts but thats not all there is to a modulated signal.key word being modulation.
 
directly heated triode, the most linear amplifying device known to man, tubes wipe the floor with any solidstate audio amplifier but maybe its not so clear cut with rf amps, all i can go on is what i have heared on the air, to my ears a triode amplifier makes even a solidstate radio sound somehow smoother/warmer than the same radio going through a solidstate amp, and thats not class C ragedyass audio, im comparing homebrew triode amps and linearamp uk tubers against yaesu and icom solidsate, they both distort but tubes sound less dissonant to my ears, if your home hifi is not all tubes then you prolly wont tell any difference with the radio sounds either.
 
NorthStar said:
All AM Radio BroadCast Stations that cover any kind of regional coverage are tube.
Click to expand...

Nope. Most AM boradcast stations are running transisitors. At least the BIG guys running 50,000 watts are. And they are digital transmitters. KFI is running the Harris DX50. The old Continental 317C is a back-up (my favorite). The newer digital transmitters are more efficient than the older tube transmitters. I can go into painful detail, but most wouldn't get it, nor would they care.

If you want some good reading, look at the Class-E amplifier info found all over the web. Maybe a few lights will come on.

For me, I like tubes best! Always have, always will. But, technology marches on.
 

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