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TheGimp 17th August 2012 12:13 PM

The end of tubes?
The article was on our intranet, and I can't find it in a google search. I suspect the link I've attached is not reachable, but added it just in case it is.

It seems the last bastion of tubes is high power high frequency RF, and that niche may be closing to SS technology.

To quote a oft seen sign,

"The End is Near!"

Solid State Direct Drive Technology at CAARI 2012
At the CAARI, one of the most important international conferences on accelerator applications, Corporate Technology gave an invited talk about the economic efficiency of Solid State Direct Drive technology.
Monday, August 13, 2012

CAARI 2012 (International Conference Application of Accelerators in Research and Industry) was held beginning of August in Fort Worth, Texas, USA. Latest results on accelerator technology and physics as well as their industrial applications were discussed at this conference. The congress provided an international forum for scientific discovery, insight into new developments, industrial applications and interdisciplinary research results.

Healthcare Technology and Concepts of Corporate Technology (CT) presented their latest results on Solid State Direct Drive™ technology and their application in industrial accelerators. The technology was developed by this CT team. Oliver Heid gave an invited plenary talk on emerging RF Accelerator Technologies with outlining the possibility to design much more efficient and compact accelerators.

Semiconductor RF Pulse Power

The goal in designing UHF RF sources for particle accelerators is to achieve high energy levels (up to Megawatt in the range of 300 to 3000 MHz) efficiently. Pulsed power vacuum tubes are today’s established solution. Their low efficiency as well as their limited reliability is a challenge. Failure of a tube leads to a complete unit failure and is a major cause for downtime of accelerators. Ways out of this dilemma need to be found.

Today, solid state amplifiers are increasingly replacing traditional vacuum tube technology (e.g. Klystrons). They offer the perspective of lower cost, better reliability and reduced maintenance than vacuum tubes. Up to now silicon based semiconductors were used thus still staying behind the power of vacuum tube technology.

SiC RF Power Module

The Solid State Direct Drive™ technology, developed by CT, uses modular, transistorized high power solid state RF-modules based on silicon carbide as an inherently distributed RF-source. Silicon carbide is much more heat and x-ray resistant compared to silicon based semiconductors. Due to the fast and robust body diode of the SiC-JFET, no external freewheeling diode or circulator needs to be integrated which makes the RF-module very compact and reliable. This new RF module design allows a complete new approach to build a power combiner, which can now achieve power levels in the Megawatt range making it compatible to today’s vacuum tube technology.

This innovation results in a paradigm shift leading to a compact, energy and cost efficient design with high energy efficiency, low cost of ownership and increased reliability. In his presentation, Oliver Heid demonstrated that this

VA2GXB 18th August 2012 09:05 PM

Are plates for large-format photography available? Yup. That tech went out at the turn of the last century. People still get about on horseback :)

kevinkr 18th August 2012 09:27 PM

Even if high power RF tube applications go solid state I doubt it will have much if any effect on the manufacture of audio tubes.

chris661 18th August 2012 09:33 PM


There's still plenty of guitarists around (me being one of them). I suspect guitarists using valve amps will never completely be irradicated.

tsiros 18th August 2012 10:17 PM

At some point in the future, film, tube amps, will die out, in the commercial/etc sector... much like horse carriages, candles (for lighting) and tubes for computing

doesn't mean they will stop being made or that they will stop being used by hobbyists.

so in short, the question is dumb (sorry for being blunt)

smoking-amp 18th August 2012 10:59 PM

Seeing as the technology for robust heaterless cathodes using thin film tunneling have been around for over ten years now, I have to wonder if the tube manufacturers are reading the tech news anymore. That UK firm that made CRT cathodes went bust too after trying to make a 12AX7 with old CRT technology. I don't see any audio tubes without the filaments yet either. They're next. Writing is on the wall.

TheGimp 19th August 2012 05:04 AM

I'm sure that as long as there is a demand by guitarist and audiophiles there will be vacuum tubes for audio purposes.

However, I wonder how long they will be made for other commercial purposes.

Transmitters are gradually converting to SS.

It looks like accelerators are converting now.

The only other application I am aware of is X-Ray and there are some solid state emitters although I suspect they are not efficient enough to displace x-ray tubes.

Where else are tubes used commercially?

Wavebourn 19th August 2012 05:12 AM

In my last project I am using a pair of output devices, one being a vacuum tube, another is SiC JFET. Such combination is quite promising.

smoking-amp 19th August 2012 04:15 PM

Any P channel SiC Fets around yet?

ChrisA 19th August 2012 07:59 PM


Originally Posted by TheGimp (
The article was on our intranet, and I can't find it in a google search. I suspect the link I've attached is not reachable, but added it just in case it is.

It seems the last bastion of tubes is high power high frequency RF, and that niche may be closing to SS technology.

To quote a oft seen sign,

"The End is Near!"...

The author is factually wrong. It is not "opinion" one can measure the total number of vacuum tubes produced world wide and pllot that number over time. In recent years the number is trending upward from a low point a few decades ago.

The major consummer of new production tubes are guitar players and there are a half dozen factories in Russia, Europe and China who are supplying this demmand for tubes.

It just so happens the HiFi stereo systems use (or can use) the same tubes. Power tubes like the 6550, 6L6, KT88, EL34 and EL84 are used by both music production and music re-production. Same goes for preamp tubes.

Yes, one day some exotic tubes may go out of production and the last old tube might fail but we will always have a supply that to all those millions of "wants-be" musicians who like me want good tube amps but can barely play.

I build both kinds of amps. The HiFi amps simpler but made with bigger transformers but both use the same tubes.

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