Yes, I know I'm digging up a thread after more than a year of inactivity, but this is an interesting subject.
Something I read on this webpage: Miniature vacuum tubes with cathodes of high-field-emitting carbon nanotubes are currently under study at Agere Systems in Murray Hill, NJ. A triode with amplification factor of 4 has been constructed, with an anode-cathode spacing of 220 ìm, and a pentode is planned. Vacuum tubes may return to electronic technology! See Physics Today, July 2002, pp. 16-18.
For those of you who subscribe to Physics Today, you can read the article here
A little off-topic, but something that may be of interest to those of you who think that the first integrated circuits were made by Robert Noyce and Jack Kilby in the late 1950s.
Here is an article about what is pretty much an integrated circuit by Siegmund Loewe way back in 1926! Not only that, it may even be the invention of the metal film resistor...
Valves were there first
Back on topic, I'd probably have to admit I like valves for completely irrational reasons (there's just something there about those glass bottles making music) - but nostalgia can't be one of them since they were basically "dead" by the time I was born. As long as there are silly, irrational, younger people like me picking up this hobby, (and there seem to be quite a few on this forum alone) the usage of valves won't die any time soon. Anyway, even if new production stops, there is quite a lot of NOS around - maybe not NOS 300Bs or 7242s, but unwanted things that will still work well.
About immortalising the valves so they can be reproduced in the future... basically what we need is the specifications of the interelectrode distances, the grid wire gauge and pitch and other physical parameters, plus the formulation of the cathode coating and they should be immortalised forever!
Something I read on this webpage: Miniature vacuum tubes with cathodes of high-field-emitting carbon nanotubes are currently under study at Agere Systems in Murray Hill, NJ. A triode with amplification factor of 4 has been constructed, with an anode-cathode spacing of 220 ìm, and a pentode is planned. Vacuum tubes may return to electronic technology! See Physics Today, July 2002, pp. 16-18.
For those of you who subscribe to Physics Today, you can read the article here
A little off-topic, but something that may be of interest to those of you who think that the first integrated circuits were made by Robert Noyce and Jack Kilby in the late 1950s.
Here is an article about what is pretty much an integrated circuit by Siegmund Loewe way back in 1926! Not only that, it may even be the invention of the metal film resistor...
Valves were there first
Back on topic, I'd probably have to admit I like valves for completely irrational reasons (there's just something there about those glass bottles making music) - but nostalgia can't be one of them since they were basically "dead" by the time I was born. As long as there are silly, irrational, younger people like me picking up this hobby, (and there seem to be quite a few on this forum alone) the usage of valves won't die any time soon. Anyway, even if new production stops, there is quite a lot of NOS around - maybe not NOS 300Bs or 7242s, but unwanted things that will still work well.
About immortalising the valves so they can be reproduced in the future... basically what we need is the specifications of the interelectrode distances, the grid wire gauge and pitch and other physical parameters, plus the formulation of the cathode coating and they should be immortalised forever!
My dear friends,
Let me tell how things go around here.
But remember, this is not to be generalized, I strongly hope!
Some kids, around making noise with a 500W portable 5"x5" CD player.
Hey kids, doya like to hear some good music?
No, no thanks uncle, we don't like that old sound!
Hey kids, if you don't came to hear my old sound you'll gonna a hear nothing for days!
They came to my room (laboratory/lissening room) I turn on my 25+25W 807 Class AB PP pentode conf. plus exponentian horn rear loaded full ranges with a little extra twetter.
All gets seated ad in silence. I put their loved CD on and....
After the lissening: oooooooooooooo........... we had never heard music like that
Is that the matter of fact that young people don't love good valve sound? Do they have never stared at a real instrumental music?
Have they never lissen a real violin, o a viola or a flute? NEVER!
This is why one chip 5KW amp are sold toghether with a 5.1 or a 7.1 or 13.1 or whatever else.1 garbige.
This apply to italians youngsters .... or ... not?
Let me tell how things go around here.
But remember, this is not to be generalized, I strongly hope!
Some kids, around making noise with a 500W portable 5"x5" CD player.
Hey kids, doya like to hear some good music?
No, no thanks uncle, we don't like that old sound!
Hey kids, if you don't came to hear my old sound you'll gonna a hear nothing for days!
They came to my room (laboratory/lissening room) I turn on my 25+25W 807 Class AB PP pentode conf. plus exponentian horn rear loaded full ranges with a little extra twetter.
All gets seated ad in silence. I put their loved CD on and....
After the lissening: oooooooooooooo........... we had never heard music like that
Is that the matter of fact that young people don't love good valve sound? Do they have never stared at a real instrumental music?
Have they never lissen a real violin, o a viola or a flute? NEVER!
This is why one chip 5KW amp are sold toghether with a 5.1 or a 7.1 or 13.1 or whatever else.1 garbige.
This apply to italians youngsters .... or ... not?
Layberinthius said:
I started with tubs in the 1950's
.......and I can assure you I will stay with tubes until I run out of emission and get put in a glass coffin ....you are right in your assumption that in decades to come that there will probably be only a handfull of standard tubes available . More serious is the gradual decline of output transformer knowledge....this component has more influence on sound than the tubes themselves....circuit debugging....and skills thereof........it's becoming hard to find anyone of the present generation who is a bull on the bench who can botch up a good high B+ and occasionally get stung by it and staying alive .... Sadly enthusiam stimulii is going the b way for good....
rich
solutions at hand
The main drawbacks to present day acceptance of tubes, high voltage and filaments for emission, are readily fixable using present day technology. Just sitting there, waiting to be done.
Its possible to build multi-ampere low voltage tubes nowadays. Have a look at these journals: Physics World, October 2000, page 25 to 26 or Physical Review Letters 2000 Vol. 85 page 864.. Two scientists, Vu Thien Binh and Christophe Adessi, have solved the problem of a room temperature thermionic emitter 50 years too late. They use a 50 nm film of Titanium oxide on a nickel plate as a cathode. It has a mere 0.1 electron volt thermal barrier which is satisfied easily by just room temperature. The technique is robustly stable in the normal vacuum tube environment against adsorbed surface contaminants as well as ion bombardment. (the field emitter techniques, like the nanotubes, etc, are not) It also has good current emission density.
Without the need for filaments or heaters, one can make large area flat sheet cathodes for high current. The whole assembly would consist of a flat sandwich of cathode sheet, laser micro-perforated grid sheet, and a copper plate with a TO-247 like mounting tab for heatsinking. Ceramic insulation layers between the sheets, and all vacuum sealed. With close sheet spacing, the plate voltages can be brought down to safe levels, like 48V.
Don
The main drawbacks to present day acceptance of tubes, high voltage and filaments for emission, are readily fixable using present day technology. Just sitting there, waiting to be done.
Its possible to build multi-ampere low voltage tubes nowadays. Have a look at these journals: Physics World, October 2000, page 25 to 26 or Physical Review Letters 2000 Vol. 85 page 864.. Two scientists, Vu Thien Binh and Christophe Adessi, have solved the problem of a room temperature thermionic emitter 50 years too late. They use a 50 nm film of Titanium oxide on a nickel plate as a cathode. It has a mere 0.1 electron volt thermal barrier which is satisfied easily by just room temperature. The technique is robustly stable in the normal vacuum tube environment against adsorbed surface contaminants as well as ion bombardment. (the field emitter techniques, like the nanotubes, etc, are not) It also has good current emission density.
Without the need for filaments or heaters, one can make large area flat sheet cathodes for high current. The whole assembly would consist of a flat sandwich of cathode sheet, laser micro-perforated grid sheet, and a copper plate with a TO-247 like mounting tab for heatsinking. Ceramic insulation layers between the sheets, and all vacuum sealed. With close sheet spacing, the plate voltages can be brought down to safe levels, like 48V.
Don
packaging
You have a point about appearance. They could still be put in glass bottles for purists of course. But if you want them for 50 cents apiece, they are going to have to look like TO-247s.
One can look at the solution in another way however. Just use them for OTL outputs, and hide them inside on a heatsink panel. The other small signal front end tubes still get mounted top-side and one can use glowing NOS for that. TO-247 tubes with 100V, 5A specs and 50 packed to a plastic sleeve at 0.50 each is something I would love to get my hands on.
Since I'm getting tired of waiting for these to arrive in the mail from Mouser ..., I'm trying another approach in the meantime. A complementary bipolar transistor output stage with 6CM3 damper diodes in series with the bases. This converts their transfer characteristics to 3/2 power law just like tubes. (current out is 3/2 power of voltage in) Only drawback is they now look like pentodes with high output impedance. That can be fixed however by using some partial "cathode" feedback, or just full cathode feedback, (ie, emitter followers in this case actually). Could go "circlotron" style output to get just 50% "cathode" feedback I guess.
Don
You have a point about appearance. They could still be put in glass bottles for purists of course. But if you want them for 50 cents apiece, they are going to have to look like TO-247s.
One can look at the solution in another way however. Just use them for OTL outputs, and hide them inside on a heatsink panel. The other small signal front end tubes still get mounted top-side and one can use glowing NOS for that. TO-247 tubes with 100V, 5A specs and 50 packed to a plastic sleeve at 0.50 each is something I would love to get my hands on.
Since I'm getting tired of waiting for these to arrive in the mail from Mouser ..., I'm trying another approach in the meantime. A complementary bipolar transistor output stage with 6CM3 damper diodes in series with the bases. This converts their transfer characteristics to 3/2 power law just like tubes. (current out is 3/2 power of voltage in) Only drawback is they now look like pentodes with high output impedance. That can be fixed however by using some partial "cathode" feedback, or just full cathode feedback, (ie, emitter followers in this case actually). Could go "circlotron" style output to get just 50% "cathode" feedback I guess.
Don
Hmm I wonder what I was drinking back then, coke cola thats it!
I'm quite surprised by the sudden upsurge in interest this thread has taken but by all means keep it coming! it can only help the vacuum tube.
Now, I think that when I made the reference to religion it was that the idea of religion has become the most redundant form of information passage which flows through the many generations of people whom come and pass from this earth, I don't want to simplify it any further than that unless I'll have problems.
Larry Lomax, I've found that young whippersnappers around my area has apsoloutley no interest in high fidelity anymore and it seems that just the lyrics or bass synthesized poop is all that matters.
In order to get youngsters interested in hi-fi reproduction which as so happens uses valves we may need to produce a line of low-cost systems which have the modern cons of CD/DVD-A/MP3 and other assorted formats in a small and easy to use cabinet but by all means display the tubes!, this would be hard while keeping low cost and efficient components within a budget and physical size restraints of speakers and the amplifier itself under control.
Maybe show them exactly what a pentode looks like, create an old-style open-plate 'cross-section' tube which gives the performance of a KT88 and make it glow,I'm sure that blue electron glow can be reproduced and enhanced with nearly no ill effects of operation and by then we may just find ourselves selling amplifiers en-mass.
"Wow look at it, it glows blue at the beat of the music!"
I'm all-for DIY solid state audiophiles, I'm attacking merely some commercial producers here:
Get dirty, if you can't beat em outright, join them, by all means add those extra blue leds but whatever you do, BUT don't change it into a magic box with nothing BUT flashing lights.
The commercial SS world by no means have clean hands for example:
#1 Circuit designs aren't exactly simple, a signal feed might go through 6-12 inches of PCB track before it finds an IC which will actually use it, then after that go through some more.
#2 The commercial only, NOT DIY SS users use digital processing to cover up incompetence.
#3 Features are running rampant in the amplifier when truly what is the amplifier supposed to do?, you're not going to use those features at the end of the day when you're tired are you?
#4 If you replaced those features with cold hard proven designs and good components at the end of the day the user is going to sit down and actually listen to lovely music and not fiddle with the feature button to try and figure out which cheap DSP function sounds best for that music.
#5 Any transport system that uses digital in my book is a scam, but I have no experience in this field, however, when it comes to spending $4000 on a new digitally-enhanced transport medium and source I'll stick with my Analog thanks, Because it just isn't worth it.
#6 How many people do you know whom have bought high-end digital transport capable equipment and never tried analog first or after? and never will? but then claim that anything digital is superior? there are far more people like this than you think, try 3/4 of the WORLD!.
If you are to target consumers and lets face it, if tubes are going to survive then it is going to have to be a consumer joe-average product, then by all means create a vacuum tube which appeals to consumers and say on the base of the amplifier on display "signal goes into the grid and comes out of the plate, this uses the natural amplifying characters of atoms themselves!" or some bull like that but hey that sounds just like the trash you find on commerical amps these days doesn't it?
And with no knobs dials or displays, its easier to use so there will be an ENORMOUS response to the "older" generations. *cough* (sorry but I'm getting pretty old myself so it kind of levels out..)
It's an interesting thought but remember tubes arent exactly a mainstream tech, whatever influential person reads this thread and decides that he can make money out of tubes had better be careful remember no matter how rich you are, we only have one chance, tubes have been around for a while and if we don't do something soon it is going to end forever, in example: low-frequency Transformers won't be around forever and neither will a LOT of other components which support our love.
I'm quite surprised by the sudden upsurge in interest this thread has taken but by all means keep it coming! it can only help the vacuum tube.
Now, I think that when I made the reference to religion it was that the idea of religion has become the most redundant form of information passage which flows through the many generations of people whom come and pass from this earth, I don't want to simplify it any further than that unless I'll have problems.
Larry Lomax, I've found that young whippersnappers around my area has apsoloutley no interest in high fidelity anymore and it seems that just the lyrics or bass synthesized poop is all that matters.
In order to get youngsters interested in hi-fi reproduction which as so happens uses valves we may need to produce a line of low-cost systems which have the modern cons of CD/DVD-A/MP3 and other assorted formats in a small and easy to use cabinet but by all means display the tubes!, this would be hard while keeping low cost and efficient components within a budget and physical size restraints of speakers and the amplifier itself under control.
Maybe show them exactly what a pentode looks like, create an old-style open-plate 'cross-section' tube which gives the performance of a KT88 and make it glow,I'm sure that blue electron glow can be reproduced and enhanced with nearly no ill effects of operation and by then we may just find ourselves selling amplifiers en-mass.
"Wow look at it, it glows blue at the beat of the music!"
I'm all-for DIY solid state audiophiles, I'm attacking merely some commercial producers here:
Get dirty, if you can't beat em outright, join them, by all means add those extra blue leds but whatever you do, BUT don't change it into a magic box with nothing BUT flashing lights.
The commercial SS world by no means have clean hands for example:
#1 Circuit designs aren't exactly simple, a signal feed might go through 6-12 inches of PCB track before it finds an IC which will actually use it, then after that go through some more.
#2 The commercial only, NOT DIY SS users use digital processing to cover up incompetence.
#3 Features are running rampant in the amplifier when truly what is the amplifier supposed to do?, you're not going to use those features at the end of the day when you're tired are you?
#4 If you replaced those features with cold hard proven designs and good components at the end of the day the user is going to sit down and actually listen to lovely music and not fiddle with the feature button to try and figure out which cheap DSP function sounds best for that music.
#5 Any transport system that uses digital in my book is a scam, but I have no experience in this field, however, when it comes to spending $4000 on a new digitally-enhanced transport medium and source I'll stick with my Analog thanks, Because it just isn't worth it.
#6 How many people do you know whom have bought high-end digital transport capable equipment and never tried analog first or after? and never will? but then claim that anything digital is superior? there are far more people like this than you think, try 3/4 of the WORLD!.
If you are to target consumers and lets face it, if tubes are going to survive then it is going to have to be a consumer joe-average product, then by all means create a vacuum tube which appeals to consumers and say on the base of the amplifier on display "signal goes into the grid and comes out of the plate, this uses the natural amplifying characters of atoms themselves!" or some bull like that but hey that sounds just like the trash you find on commerical amps these days doesn't it?
And with no knobs dials or displays, its easier to use so there will be an ENORMOUS response to the "older" generations. *cough* (sorry but I'm getting pretty old myself so it kind of levels out..)
It's an interesting thought but remember tubes arent exactly a mainstream tech, whatever influential person reads this thread and decides that he can make money out of tubes had better be careful remember no matter how rich you are, we only have one chance, tubes have been around for a while and if we don't do something soon it is going to end forever, in example: low-frequency Transformers won't be around forever and neither will a LOT of other components which support our love.
It isn't just Newcastle. In a big city like Melbourne, it's just as bad - if not worse.Layberinthius said:
While valves are really cool (no, not literally), as you have noted, many of the supporting components are becoming rare indeed. Polycarbonate, polystryerne and silvered mica capacitors are becoming quite rare, and probably more significantly, the body of knowledge with regards to audio transformers suitable for hi-fi seems to be shrinking.
Also, I have found valves (and vinyl for that matter) are now widely misunderstood. Fear of ongoing cost, (and poorly designed commercial equipment - who must remain nameless, using 1200mF input capacitors with valve rectifiers, or running valves several times over ratings) make people think that valves are unreliable, and require constant maintenance and care far above that required for silicon devices. But used properly, valves can last for many years indeed - and probably long after cheapo transistor amps are sent to the tip.
The vast majority of the population also has no idea what goes on inside an amplifier. Many don't even know what an amplifier really is, and what it does. When a friend of mine saw hot glass glowy things and a black spinny disc thing, his comments were that valves and vinyl were no good because they had to try to reproduce all the music at once, while his CD player and transistor amp at home kept each instrument and vocal separate until it reached the speaker, resulting in better sound. Obviously total, utter rubbish most likely instilled on an ignorant consumer by an unscrupulous salesperson.
Sorry to rain on your parade, but due to a lack of general public interest for valve amps, and increased production costs due to the fact that really large scale produciton of the required components no longer occurs, I truly doubt the glow of valves will once again grace most people's living rooms.
Where is the world going to?
Have you heard about Quarzial Cable? (Coaxial Cable)
A good heart? Must be made of a strong copper wire dipped in to a pot with ground and manure mixture!
Why does a transistor amp sounds metallic? Becouse of the TO3 transistors! So why does a transistor amp with SOT93 doesn't sound "Plastic"? And the tubes "Glassy"?
Tube amps sounds warm becouse of the hot filament! So direct heated triodes sounds warmer than indirect heated ones!
How can people believe this? Are they really so uninformed? Or they love to live in a world like Matrix? Munching an ideal pice of juicy steack?
Yup, they do!
By!
Larry Lomax said:
Actually, I once read something (possibly promotional material) which stated emphatically that the sound of valve amps were different from transistor amps because the vacuum in the valve filtered out distortion from the music, and that the area which the current passes through is much larger in a valve than an transistor, so the sound is more open!
By the way, if this is the future for valves, I want no part in it.
An externally hosted image should be here but it was not working when we last tested it.
Actually, I think the future of high quality analog components themselves is at risk. Since digital processing requires little in the way of tolerances in the associated resistors, pots etc. component manufacturers are ceasing to build to anything but the lowest common denominator. Who can blame them? The computer/electronics industry wants 20 billion parts & the audio guys who care need 10,000!
This was brought home to me with a product design for sound reinforcement use (a subwoofer equalizer if you're interested). Basically, I wanted analog but this very well respected manufacturer could not produce a product at a price point they could actually sell without going digital. The main cause of this was the price of the components needed to build a quality analog product.
The guys building $750K mixing consoles are not worried about a $30 pot but if you're trying to design & build quality, mass market products the analog future does not look good.
P
This was brought home to me with a product design for sound reinforcement use (a subwoofer equalizer if you're interested). Basically, I wanted analog but this very well respected manufacturer could not produce a product at a price point they could actually sell without going digital. The main cause of this was the price of the components needed to build a quality analog product.
The guys building $750K mixing consoles are not worried about a $30 pot but if you're trying to design & build quality, mass market products the analog future does not look good.
P
Hi,
Ah....A similar info appeared in the French mag L'Audiophile about twenty years ago.
Nano tubes, mini-triodes...
Can't quite recall what they were called but the idea was to build some sort of TFT screen with a yield of several thousands of microscopically small triodes...
For as long as I can remember some people always told me not to bother with tubes (on a business-scale) as those thing were moribound and not worthy of a penny of investment...
Well, after all those years they're still more or less at the same places where they were most used back then.
I wouldn't want to have to count the number of so called "obsolete" tubes that are still in daily use all over the world; from a simple thyratron to photomultipliers to the big RF transmitters, they're plentiful.
While most people won't associate some household appliances with vacuum tube technology, the fact remains that they're everywhere: microwave ovens, faxmachines etc all contain some form of vacuum tube.
Will we ever see the top quality professional tubes of yesteryear?
Quite unlikely.
Could vacuum tubes be bettered in every respect nowadays using modern manufacturing processes?
Absolutely....
But...Would you want to pay the price?
I doubt it.
For such small quantities of dedicated devices we'd be paying prices well into Rolls Royce territory, no doubt about that.
OTOH, current manufacture tubes have never been cheaper; QC is relaxed, some manufacturer's vacuum pumps are well worn but, let's face it: most users often replace their tubes well before they're worn out anyway.
Did you know that a, say Philips, SQ (Special Quality) tube was guaranteed to be within 70% of its typical rating after several thousands of hours' use by the factory?
Those SQ tubes costed roughly a smallish "month's salary" a piece back in those days....
I hate to think what they'd cost now.
According to studies carried out some years back, about the best investment you can make is buying NOS tubes.
No idea whether that's this valid today but it looks like it...
Back in the Mid-Eighties I sold the common as mud ECC/12A*** series of tubes of than current manufacture for about 3 to 4 USD each.
NOS was usually more than twice as much and was already hard to come by in quantities of good quality....
All in all I don't think there's all that much to complain about really.
Unless you start listening to the best NOS tubes of course...
Cheers,
Ah....A similar info appeared in the French mag L'Audiophile about twenty years ago.
Nano tubes, mini-triodes...
Can't quite recall what they were called but the idea was to build some sort of TFT screen with a yield of several thousands of microscopically small triodes...
For as long as I can remember some people always told me not to bother with tubes (on a business-scale) as those thing were moribound and not worthy of a penny of investment...
Well, after all those years they're still more or less at the same places where they were most used back then.
I wouldn't want to have to count the number of so called "obsolete" tubes that are still in daily use all over the world; from a simple thyratron to photomultipliers to the big RF transmitters, they're plentiful.
While most people won't associate some household appliances with vacuum tube technology, the fact remains that they're everywhere: microwave ovens, faxmachines etc all contain some form of vacuum tube.
Will we ever see the top quality professional tubes of yesteryear?
Quite unlikely.
Could vacuum tubes be bettered in every respect nowadays using modern manufacturing processes?
Absolutely....
But...Would you want to pay the price?
I doubt it.
For such small quantities of dedicated devices we'd be paying prices well into Rolls Royce territory, no doubt about that.
OTOH, current manufacture tubes have never been cheaper; QC is relaxed, some manufacturer's vacuum pumps are well worn but, let's face it: most users often replace their tubes well before they're worn out anyway.
Did you know that a, say Philips, SQ (Special Quality) tube was guaranteed to be within 70% of its typical rating after several thousands of hours' use by the factory?
Those SQ tubes costed roughly a smallish "month's salary" a piece back in those days....
I hate to think what they'd cost now.
According to studies carried out some years back, about the best investment you can make is buying NOS tubes.
No idea whether that's this valid today but it looks like it...
Back in the Mid-Eighties I sold the common as mud ECC/12A*** series of tubes of than current manufacture for about 3 to 4 USD each.
NOS was usually more than twice as much and was already hard to come by in quantities of good quality....
All in all I don't think there's all that much to complain about really.
Unless you start listening to the best NOS tubes of course...
Cheers,
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.