pseudo-triode
Hi (to all)... !
When wiring pentodes in triode mode, the rule of thumb is to connect g2 to a, preferably thru 200 ohms - 1k ohms resistor (grid stopper to prevent oscillation).
Most pentodes to not have a separate pin connection for g3 -- one of the very few that comes to mind is the EL34.
In order to have a true pseudo triode, you should connect g3 to anode, as well. If you do not, it will still work as pseudo triode, but you would loose the possibility to make it as triodelike as possible.
It's up to you and your taste, bat-eared people might hear some difference, or make themselves believe that they do hear it. Anyway, it will work and quality as pseudo-triode both ways. Just do not forget the grid stoppers!
Further on this topic, I recall having seen some true triode EL34s being manufactured without the g2 and g3 material, in order not to interfere with the flow of electrons. Because, you know -- the electrons will not reach the anode and the g2 and g3 material at the same time, actually.
Best regards,
Aleksandar
PS
If you need the sound of the triode with the power of the pentode, try the RH34!
) (this was a little self-advertising)
Hi (to all)... !
When wiring pentodes in triode mode, the rule of thumb is to connect g2 to a, preferably thru 200 ohms - 1k ohms resistor (grid stopper to prevent oscillation).
Most pentodes to not have a separate pin connection for g3 -- one of the very few that comes to mind is the EL34.
In order to have a true pseudo triode, you should connect g3 to anode, as well. If you do not, it will still work as pseudo triode, but you would loose the possibility to make it as triodelike as possible.
It's up to you and your taste, bat-eared people might hear some difference, or make themselves believe that they do hear it. Anyway, it will work and quality as pseudo-triode both ways. Just do not forget the grid stoppers!
Further on this topic, I recall having seen some true triode EL34s being manufactured without the g2 and g3 material, in order not to interfere with the flow of electrons. Because, you know -- the electrons will not reach the anode and the g2 and g3 material at the same time, actually.
Best regards,
Aleksandar
PS
If you need the sound of the triode with the power of the pentode, try the RH34!
) (this was a little self-advertising)
Re: pseudo-triode
Hi Mr. Kitic,
I find RH34 in Elvis Rakic website, but no rfb value there.
Should it be 100K ?
and if i want to make a true pseudo triode, may I just disconnect g3 from cathode and connect it to anode via 200 Ohm resistor ?
rgds,
Gede
Alex Kitic said:In order to have a true pseudo triode, you should connect g3 to anode, as well. If you do not, it will still work as pseudo triode, but you would loose the possibility to make it as triodelike as possible.
If you need the sound of the triode with the power of the pentode, try the RH34!
Hi Mr. Kitic,
I find RH34 in Elvis Rakic website, but no rfb value there.
Should it be 100K ?
and if i want to make a true pseudo triode, may I just disconnect g3 from cathode and connect it to anode via 200 Ohm resistor ?
rgds,
Gede
RH34 and pseudo-triode
Hi to all!
First of all, whoever might be interested in the RH34 schematics should contact me directly via e-mail. You can find my e-mail address both on Elvis's and my site www.tubeaudio.8m.com
Last but not least, all RH amps can have a switch to allow transforming them from RH to pseudo-triode, even in real time (although that is not recommanded, you should first turn it off than apply the switch position...). But, the real reason for the switch to exist is to give disbelievers the opportunity to hear for themselves that the sound is the same (almost, especially for those bat eared) while the power is vastly different... and those who own extremely efficient speakers and necessitate no more power than that of a 10Y or eventually 45... well, they most probably do not need an RH amp, they need to assess their own wishes and not let themselves be commanded what to do by would-be-designers of true triode amps
Regards,
Aleksandar
Hi to all!
First of all, whoever might be interested in the RH34 schematics should contact me directly via e-mail. You can find my e-mail address both on Elvis's and my site www.tubeaudio.8m.com
Last but not least, all RH amps can have a switch to allow transforming them from RH to pseudo-triode, even in real time (although that is not recommanded, you should first turn it off than apply the switch position...). But, the real reason for the switch to exist is to give disbelievers the opportunity to hear for themselves that the sound is the same (almost, especially for those bat eared) while the power is vastly different... and those who own extremely efficient speakers and necessitate no more power than that of a 10Y or eventually 45... well, they most probably do not need an RH amp, they need to assess their own wishes and not let themselves be commanded what to do by would-be-designers of true triode amps
Regards,
Aleksandar
Re: pseudo-triode
Electron transit time becomes important at microwave frequencies but is entirely negligible at audio and even low RF. Assuming 400V on the anode, the electrons will strike it at almost 12,000,000m/s* Eyeballing an EL34, the furthest point on the anode from the central cathode structure is about 8mm, so assuming uniform acceleration, an electron will take 1.3ns to traverse that entire distance.
I really don't think even large discrepancies in a total transit time that amounts to less than one hundredth of a degree of phase at 20kHz are going to be a problem...
Oh, and to get back to the original poster's question, connecting g3 to a pentode's anode when in triode mode gives a small (but measurable) increase in mutual conductance. I've no idea if it's audible, but if it's free and it doesn't cause oscillation, why not have it?
*About 26 million miles per hour
Alex Kitic said:
Electron transit time becomes important at microwave frequencies but is entirely negligible at audio and even low RF. Assuming 400V on the anode, the electrons will strike it at almost 12,000,000m/s* Eyeballing an EL34, the furthest point on the anode from the central cathode structure is about 8mm, so assuming uniform acceleration, an electron will take 1.3ns to traverse that entire distance.
I really don't think even large discrepancies in a total transit time that amounts to less than one hundredth of a degree of phase at 20kHz are going to be a problem...
Oh, and to get back to the original poster's question, connecting g3 to a pentode's anode when in triode mode gives a small (but measurable) increase in mutual conductance. I've no idea if it's audible, but if it's free and it doesn't cause oscillation, why not have it?
*About 26 million miles per hour
Hello,
I have recently conducted some tests with G3 connected to the anode.
Here is the distortion spectrum of an EL34 at full undistorted power with G3 connected to the cathode (the normal way):
And here is the same circuit with G3 connected to the anode:
As you can see the measured distortion figure is about equal but the harmonic distribution is very different indeed.
Best regards
Michael
I have recently conducted some tests with G3 connected to the anode.
Here is the distortion spectrum of an EL34 at full undistorted power with G3 connected to the cathode (the normal way):
An externally hosted image should be here but it was not working when we last tested it.
And here is the same circuit with G3 connected to the anode:
An externally hosted image should be here but it was not working when we last tested it.
As you can see the measured distortion figure is about equal but the harmonic distribution is very different indeed.
Best regards
Michael
Hi tubemaster,
Were G2 and G3 directly connected to anode or via resistors? Also curious if you looked at frequecy response. This is conditional because I didn't write down the measurements, but I seem to recall playing with an E180F that tying G3 to cathode resulted in a wider bandwidth up top compare to anode connect.
Were G2 and G3 directly connected to anode or via resistors? Also curious if you looked at frequecy response. This is conditional because I didn't write down the measurements, but I seem to recall playing with an E180F that tying G3 to cathode resulted in a wider bandwidth up top compare to anode connect.
Apart from the most interesting analysis done by Tubemaster (post #7), just something about max. ratings. I have not done any tests, but am just wondering whether G3, being normally at common potential, is made - mounted, if you will - to reliably handle the voltage swing that an EL34 anode + G2 can tolerate as triode.
I have never chopped one open and inspection from outside reveals nothing to get nervous about, if they are all constructed the same way. Still, just a thought.
I have never chopped one open and inspection from outside reveals nothing to get nervous about, if they are all constructed the same way. Still, just a thought.
electron speed
Point is, whether the law of relativity applies to this issue in the same way as it applies to almost everything in our lives -- with statistical accuracy meaning that such differences in arrival time of the electrons, which indeed exist however small, can be considered irrelevant. But, they obviously are not, since it is about other issues as well, not only on whether the electrons move fast or not.
To further the issue a little bit, let me reming you all of the fact that DH tubes tend to have longer filament/cathodes than the anode, although wrapped in g1 for the whole length, for some reason (of course I know which reason it is...). If such simple engineering tricks lead to better overall results, then just rethink whether it is the same if g2 and g3 get in the way of the electrons, although being at the same potential as the anode (which in fact they will not be in exact terms, since one would use grid stopper resistors, and with a current draw, some at least infinitesimal, or less so, difference in potential will occur).
Regards,
Aleksandar
Point is, whether the law of relativity applies to this issue in the same way as it applies to almost everything in our lives -- with statistical accuracy
meaning that such differences in arrival time of the electrons, which indeed exist however small, can be considered irrelevant. But, they obviously are not, since it is about other issues as well, not only on whether the electrons move fast or not.To further the issue a little bit, let me reming you all of the fact that DH tubes tend to have longer filament/cathodes than the anode, although wrapped in g1 for the whole length, for some reason (of course I know which reason it is...). If such simple engineering tricks lead to better overall results, then just rethink whether it is the same if g2 and g3 get in the way of the electrons, although being at the same potential as the anode (which in fact they will not be in exact terms, since one would use grid stopper resistors, and with a current draw, some at least infinitesimal, or less so, difference in potential will occur).
Regards,
Aleksandar
Johan Potgieter said:
I wondered about that, too. Then I thought about the paths across the micas that could break down. If you think about it, if g3 is at 0V and is between the anode and g2 that swing from 0V to +800V in normal triode mode, will there be a problem if you place it at the same voltage as those electrodes? There is now no voltage stress across the paths to g2 or the anode, so there can't be any breakdown there. Could it break down to g1? There's certainly the potential, but if that was going to happen, it would be done by the nearer electrode structure of g2.
Alex: We don't need to worry about relativity at only 400V; you need a reasonable number of kV before relativistic effects occur. Looking at the other end of things, electrons escape from the cathode with slightly different initial velocities and although the average current is constant, it varies with time. We hear this as noise, but we'll need some very sensitive loudspeakers for it to be a problem in an EL34 output valve.
I take your point that interposing additional grids (at anode potential) must disturb the local electric field in the vicinity of the grid wires between the control grid and the anode compared to a true triode without any additional grids in the way. The question is whether it is significant. One way we could find out would be to make a valve with the means to withdraw g2 and g3 during operation to measure the effect. Alternatively, we could make a few thousand pentodes and a few few thousand of the same type (but without g2 and g3). Somehow, I don't think either test will be done.
My personal feeling is that if it looks like a duck, flies like a duck, and quacks like a duck, then it probably is a duck. Triode-strapped pentodes look sufficiently like triodes to me that I'm going to treat them as such.
Attachments
KNOWLEDGE AND KNOWLEDGEABILITY
Hi to all, expecially EC8010...
Point is, many of the participants to these forums have very limited knowledge of basic sciences (physics, math... etc.). OK, I recon that they did not go to school in ex-Yugoslavia where the school system was more complex and required more of those who wanted to study and achieve -- even than the Japanese system.
Yes, I know that most people seem to have looked somewhere outside the window while they were teaching Ohms law, or grammar, for that matter...
Still, I do not know how do people become moderators, trustees... etc. at these forums, but it seems that with a little more time and will, one can become all those things. And, when he does, he can look at people from above, or as you say "patronize" or whatever.
Of course I know of relativism etc. although it seems that some people do not... and statistics, as well... how can we define whether our answers are directed to the right person? Sometimes, when I enter forums, I get such answers from people that I truly do not understand whether its a premeditated insult of one's intelligence, or just the usual "turn on your brain before you do something" stuff? Of course, EC8010 cannot know who I am or what do I know... but if he does not, he also cannot reply in such terms as if the person whom he replies to is ignorant or whatever.
Maybe I'm too sensitive... or the anglosaxon guys are too insensitive and blunt? But fact is, whatever one does, it turns wrong. I am very dissatisfied with what these forums are turning into!
For a last word, just look around for threads... the same things being munched over and over again... the same topics in different threads, sometimes initiated by different people, but mostly attended by the same ones. With the same knowledge, or knowledgeability, or the lack thereof. To me, it seems that its an issue of fat people and feeders...
Regards to all,
Aleksandar
Hi to all, expecially EC8010...
Point is, many of the participants to these forums have very limited knowledge of basic sciences (physics, math... etc.). OK, I recon that they did not go to school in ex-Yugoslavia where the school system was more complex and required more of those who wanted to study and achieve -- even than the Japanese system.
Yes, I know that most people seem to have looked somewhere outside the window while they were teaching Ohms law, or grammar, for that matter...
Still, I do not know how do people become moderators, trustees... etc. at these forums, but it seems that with a little more time and will, one can become all those things. And, when he does, he can look at people from above, or as you say "patronize" or whatever.
Of course I know of relativism etc. although it seems that some people do not... and statistics, as well... how can we define whether our answers are directed to the right person? Sometimes, when I enter forums, I get such answers from people that I truly do not understand whether its a premeditated insult of one's intelligence, or just the usual "turn on your brain before you do something" stuff? Of course, EC8010 cannot know who I am or what do I know... but if he does not, he also cannot reply in such terms as if the person whom he replies to is ignorant or whatever.
Maybe I'm too sensitive... or the anglosaxon guys are too insensitive and blunt? But fact is, whatever one does, it turns wrong. I am very dissatisfied with what these forums are turning into!
For a last word, just look around for threads... the same things being munched over and over again... the same topics in different threads, sometimes initiated by different people, but mostly attended by the same ones. With the same knowledge, or knowledgeability, or the lack thereof. To me, it seems that its an issue of fat people and feeders...
Regards to all,
Aleksandar
Hello Aleksandar, I am sorry that you feel that I was patronizing you - that was certainly not my intention. As you say, I cannot know what you do or don't know. When you made your "time of flight" comment, I took the time to calculate from first principles the time of flight from grid to anode of an EL34 at 400V and to express that answer in a way that would be meaningful to the people who were looking out the window during their physics class. Perhaps it's a language/cultural misunderstanding, but my intention was to offer objective scientific comments, not to upset anyone. My apologies if I offended you.
This forum, like most other serious fora, has contributors whose knowledge and experience vary widely. There are casual hobbyists, academics and experienced practitioners. All are welcome. Those who have the knowledge are generous enough to share it with others who do not. This is something for which to be thankful.
Patience is sometimes needed in responding to forum members whose questions may seem naive. At the risk of "insulting" someone's intelligence (not sure what this is supposed to mean), a response may, on occasions, be aimed a little lower than the level expected by the participant asking the question. However, this is of little consequence and it is better to err on the side of caution, rather than risk a response that might be incomprehensible to the recipient. The appropriate level of dialog can usually be ascertained after a few back-and-forth messages.
This is not an intellectual contest and at no time should egos or personalities enter into it. Most forum users have the intelligence to understand this; unfortunately, there are a few who do not.
Patience is sometimes needed in responding to forum members whose questions may seem naive. At the risk of "insulting" someone's intelligence (not sure what this is supposed to mean), a response may, on occasions, be aimed a little lower than the level expected by the participant asking the question. However, this is of little consequence and it is better to err on the side of caution, rather than risk a response that might be incomprehensible to the recipient. The appropriate level of dialog can usually be ascertained after a few back-and-forth messages.
This is not an intellectual contest and at no time should egos or personalities enter into it. Most forum users have the intelligence to understand this; unfortunately, there are a few who do not.
I wish to echo Ray's sentiments. This forum is made up of people of a diverse culture and technical background. Fortunately it is for the most part a very good exchange of technical ideas remarkably free from the "audio insanity" and blatant marketing that plagues other forums.
I WAS one of those people that spent my time in physics class looking out the window (and throwing paper airplanes out the window). Never the less I kept working at it slowly, finally getting a Masters degree in Electrical Engineering at age 45. If you read any of my posts, or look at my web site, you can see that I have a considerable knowledge in the field of vacuum tube engineering, which I am trying to share with all who are interested. We should all adopt this attitude if we want our hobby to continue. We need innovation in this hobby, or we will all be doomed to build the same 300B SE or KT-88 P-P amps for ever.
In the few months that I have been on this forum, I know (from e-mails) that I have helped several people understand their problem, or take one more step closer to achieving their personal audio nirvana. At the same time I have learned a lot about vacuum tube circuits that I would have never thought about on my own. As soon as my lab is back up (it got messed up during hurricane Wilma), I have several circuits to try that I learned about right here.
This kind of experimentation, and a free exchange of ideas is what makes this forum valuble, so I will say that I am very satisfied with what these forums are turning into.
Now, a bit closer to topic, I have seen circuits published for triode strapped pentodes that tie G3 to either the plate or to the cathode. I am sure that both connections will function. Which one works best for you? That is going to be largely a matter of personal taste, and the circuit (and operating conditions) chosen.
For the thinkers out there that aren't afriad to try something new:
In another thread, I was asked about some 7094 tubes. I had never heard or these before, so I looked them up. In the process, I read about the "High Mu triode connection", G1 connected to G2 and used as the control grid. This would need to run in A2, but we know how to do that. When my lab is back up, I will try this with EL34's and some sweep tubes, and any other tube that I can think of.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=67632
I WAS one of those people that spent my time in physics class looking out the window (and throwing paper airplanes out the window). Never the less I kept working at it slowly, finally getting a Masters degree in Electrical Engineering at age 45. If you read any of my posts, or look at my web site, you can see that I have a considerable knowledge in the field of vacuum tube engineering, which I am trying to share with all who are interested. We should all adopt this attitude if we want our hobby to continue. We need innovation in this hobby, or we will all be doomed to build the same 300B SE or KT-88 P-P amps for ever.
In the few months that I have been on this forum, I know (from e-mails) that I have helped several people understand their problem, or take one more step closer to achieving their personal audio nirvana. At the same time I have learned a lot about vacuum tube circuits that I would have never thought about on my own. As soon as my lab is back up (it got messed up during hurricane Wilma), I have several circuits to try that I learned about right here.
This kind of experimentation, and a free exchange of ideas is what makes this forum valuble, so I will say that I am very satisfied with what these forums are turning into.
Now, a bit closer to topic, I have seen circuits published for triode strapped pentodes that tie G3 to either the plate or to the cathode. I am sure that both connections will function. Which one works best for you? That is going to be largely a matter of personal taste, and the circuit (and operating conditions) chosen.
For the thinkers out there that aren't afriad to try something new:
In another thread, I was asked about some 7094 tubes. I had never heard or these before, so I looked them up. In the process, I read about the "High Mu triode connection", G1 connected to G2 and used as the control grid. This would need to run in A2, but we know how to do that. When my lab is back up, I will try this with EL34's and some sweep tubes, and any other tube that I can think of.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=67632
intelligence and innovation
Hi to all!
First of all, I wish to say that I cannot believe that the phrase "insulting one's intelligence" is unknown to American/British/West European generic contributors to the phorum! Maybe in Jakarta (if the location is indeed that) the phrase is unknown. Well, I would define it as being told in your face things that are not necessarily true, where who tells eventually expects you to be in agreement with him just because of what he has already told you, your own opinion, wits or knowledge being quite unimportant. Maybe the definition is not quite correct, but I've tried to do my best.
What it does mean is that when you enter some thread, you might be explained things again and again as if the way in which these issues are seen by who explains is the only possible and exact one. Usually done by someone who has firm beliefs in what he is saying...
Well, in this case it is about relativism, and not relativism: as a matter of fact, the electrons will not reach g2 and g3 at the same time as it reaches the anode. That is completely and utterly true. Furthermore, whether this fact is rendered unimportant by speed at which the electrons travel in the vacuum tube, since the statistical incidence on the result is unimportant or negligible, is a completely different issue. But, THEY DO NOT ARRIVE AT THOSE SPOTS AT THE SAME TIME. Furthermore, it is important to note that g2 is very near the anode, g3 even closer to the anode... but in terms of electron speed, the whole travel is very short, even from the cathode to the anode. On the other hand, it is not the speed at which the electrons travel that we should necessarily take into account, but the distance from cathode to anode, from cathode to g2, and from cathode to g3... and only after such considerations see whether the fact that for instance the g2 is at approx. 60% of the distance from cathode to anode, meaning that i.e. 40% of the travel has still to be travelled to reach the anode -- is not important, just because the speed at which electrons travel is high as compared to the total distance the electron has to travel. I can only hope that this lengthy explanation is not unreadable -- but those interested will most probably read it carefully.
That said, I must stress the fact that I already said that not necessarily one can hear the difference, etc.
Further on, when finding the insistance on one's truth as "insult of another's intelligence", I also think about the fact that when we reply to people, or enter into discussion with them, we shuld "do some homework". I.E. I did some homework about our "friend" tubelab.com. It seems that this person without name (I will never cease stressing the fact that people just hide behind pseudonims, in this case the web site address) has an interesting web site, where interesting amps are presented. Well, the only important thing to stress in this case is the GOAL or MISSION STATEMENT of said person, quote:
"We need innovation in this hobby, or we will all be doomed to build the same 300B SE or KT-88 P-P amps for ever."
Well, if you ask me, maybe its innovation to introduce mos-fet or constant current sources made of solid state components... to me, its both plain hybridisation -- as opposed to pure tubes -- and not at all novelty or innovation, just take a look at the bottlehead web site and their favorite passtime "CSS application to whatever and wherever". Far from that, I indluge in pure tube circuitry, and what I might consider as my own innovations, although it is merely a concept long lost and revisited... is the RH series of amps. Furthermore, those amps can be built with tetrodes and pentodes, namely cheaper and even current production tubes, especially when compared with such subtleties as 45s. Furthermore, most people hang on 300Bs for the fact they can get some 8 or 9 Watts SE power, or to KT88 PP amps for the fact that the power will be at least 45W... those figures necessary if you do not own efficient speakers.
Aside from the discussion on the power necessary in order to use not-very-efficient speakers, namely your garden variety Hi-Fi speakers (87-90dB/W/m), it is generally better to have i.e. 4-5 W of power at 1% distortion from an EL84 SE amp in pentode RH mode, than to have the 1.5 or eventually 2 W you can get from a 45 amp (not mentioning distortion, BUT MENTIONING the price-tag difference and availability of an EL84 pentode as compared to 45s... or 845s, for that matter).
Well, I hope I have not offended anyone, at least not more than I found myself offended by blunt and not-enough-thought-thru replies. Those who do not know what RH amps are, can find info on older threads, and my site www.tubeaudio.8m.com -- where my address is always available for those who might be interested in exchanging toughts and ideas.
Most probably there would have been many other explanations and parallels to be shown to interested parties who read this thread, but you must admit that this post was almost indecently long. Suffice to say, I did not write it on-line.
Regards to all,
Aleksandar
Hi to all!
First of all, I wish to say that I cannot believe that the phrase "insulting one's intelligence" is unknown to American/British/West European generic contributors to the phorum! Maybe in Jakarta (if the location is indeed that) the phrase is unknown. Well, I would define it as being told in your face things that are not necessarily true, where who tells eventually expects you to be in agreement with him just because of what he has already told you, your own opinion, wits or knowledge being quite unimportant. Maybe the definition is not quite correct, but I've tried to do my best.
What it does mean is that when you enter some thread, you might be explained things again and again as if the way in which these issues are seen by who explains is the only possible and exact one. Usually done by someone who has firm beliefs in what he is saying...
Well, in this case it is about relativism, and not relativism: as a matter of fact, the electrons will not reach g2 and g3 at the same time as it reaches the anode. That is completely and utterly true. Furthermore, whether this fact is rendered unimportant by speed at which the electrons travel in the vacuum tube, since the statistical incidence on the result is unimportant or negligible, is a completely different issue. But, THEY DO NOT ARRIVE AT THOSE SPOTS AT THE SAME TIME. Furthermore, it is important to note that g2 is very near the anode, g3 even closer to the anode... but in terms of electron speed, the whole travel is very short, even from the cathode to the anode. On the other hand, it is not the speed at which the electrons travel that we should necessarily take into account, but the distance from cathode to anode, from cathode to g2, and from cathode to g3... and only after such considerations see whether the fact that for instance the g2 is at approx. 60% of the distance from cathode to anode, meaning that i.e. 40% of the travel has still to be travelled to reach the anode -- is not important, just because the speed at which electrons travel is high as compared to the total distance the electron has to travel. I can only hope that this lengthy explanation is not unreadable -- but those interested will most probably read it carefully.
That said, I must stress the fact that I already said that not necessarily one can hear the difference, etc.
Further on, when finding the insistance on one's truth as "insult of another's intelligence", I also think about the fact that when we reply to people, or enter into discussion with them, we shuld "do some homework". I.E. I did some homework about our "friend" tubelab.com. It seems that this person without name (I will never cease stressing the fact that people just hide behind pseudonims, in this case the web site address) has an interesting web site, where interesting amps are presented. Well, the only important thing to stress in this case is the GOAL or MISSION STATEMENT of said person, quote:
"We need innovation in this hobby, or we will all be doomed to build the same 300B SE or KT-88 P-P amps for ever."
Well, if you ask me, maybe its innovation to introduce mos-fet or constant current sources made of solid state components... to me, its both plain hybridisation -- as opposed to pure tubes -- and not at all novelty or innovation, just take a look at the bottlehead web site and their favorite passtime "CSS application to whatever and wherever". Far from that, I indluge in pure tube circuitry, and what I might consider as my own innovations, although it is merely a concept long lost and revisited... is the RH series of amps. Furthermore, those amps can be built with tetrodes and pentodes, namely cheaper and even current production tubes, especially when compared with such subtleties as 45s. Furthermore, most people hang on 300Bs for the fact they can get some 8 or 9 Watts SE power, or to KT88 PP amps for the fact that the power will be at least 45W... those figures necessary if you do not own efficient speakers.
Aside from the discussion on the power necessary in order to use not-very-efficient speakers, namely your garden variety Hi-Fi speakers (87-90dB/W/m), it is generally better to have i.e. 4-5 W of power at 1% distortion from an EL84 SE amp in pentode RH mode, than to have the 1.5 or eventually 2 W you can get from a 45 amp (not mentioning distortion, BUT MENTIONING the price-tag difference and availability of an EL84 pentode as compared to 45s... or 845s, for that matter).
Well, I hope I have not offended anyone, at least not more than I found myself offended by blunt and not-enough-thought-thru replies. Those who do not know what RH amps are, can find info on older threads, and my site www.tubeaudio.8m.com -- where my address is always available for those who might be interested in exchanging toughts and ideas.
Most probably there would have been many other explanations and parallels to be shown to interested parties who read this thread, but you must admit that this post was almost indecently long. Suffice to say, I did not write it on-line.
Regards to all,
Aleksandar
I am sorry that you feel offended enough by my reply to single me out as "a person without a name", when my name, my face, and my e-mail address is plainly stated on the web site. Many users on this (and other) forum choose "pseudonyms", I simply chose the obvious one. I have never meant to offend anyone, and I simply meant to explain that this forum is a medium for the open exchange of ideas. We all must understand that many of the ideas are the opinion of the writer, not established fact. It is up to the reader to sift through the responses and take the information that they want.
In this hobby there will always be different opinions. This is the first forum that I have visited where I actually signed up to participate because it seemed a refreshing change from some of the other forums where "flame wars" would errupt over a users choice of a particular $200 power cord.
Even though I slept through physics class, I understand that nothing (including electrons) travel at infinite speed, and that there is a definite, and measureable transit time. This is indeed a fact. There are opinions as to whether it would make an audible difference, and on this topic I remain neutral.
I still stand by the goals stated on my web site. We do need some more innovation in this hobby, or there won't be any new designs. The PowerDrive circuit is definitely a hybrid design. At the time I did that web page, I believed that the combination of CCS and mosfet follower to be unique. I am an engineer by trade, and I am choosing the best components for the job, whether they are tube or solid state. As with most engineering decisions this is based on my opinion not fact. You, or any reader is free to use the design or ignore it. My "mission" is to present these ideas in places where others can see them and use them if they so choose. There are other designs on my site that are "pure tube". I will add more when I get the time to update the site.
Yes, I agree that there are plenty of tubes out there that cost less than the 45 and 845 that are capable of great sound. I have a warehouse full of old tubes, which I am slowly sorting through and testing to find out which ones have good audio potential. It happens that I started with the 45, and the 845 because I had some, and they have a good reputation. They do give great sound, and now that I have established a reference, I have something to compare other tubes to.
One of the great things about this forum is that it is two way. I was asked about 6AV5's in another thread. Since I had some in the warehouse, I got a pair, hooked them up, compared them to other triode strapped pentodes, and was surprized by the sound that they put out. I shared the results with the participants of that thread, and they will eventually wind up on the web site. I would have likely not tried those tubes if it wasn't for this forum. Another thread got me to try 807's. That experiment was about to get underway when the hurricane struck, and all experiments have been put on hold since. Other threads have prompted future experiments that will be documented and published.
Again, I want to apologize if any one out there took my comments as an insult. I don't believe that any "insults" were intentional in this entire thread (certainly not my intention), just the differences in expression that are inevitable when dealing with an audience of a diverse cultural and technical background. I don't claim to be a technical wizard, just an average engineer who likes to experiment, and is not afraid to blow up a few parts. I intend to continue to share my experiences with anyone who can benefit by them.
Up until now I have found this forum remarkably free of the "verbal warfare" that is so common on other forums, and I hope that this one does not degenerate to a place where I must "do some homework" and investigate my readers, and potential readers, before posting for fear that someone won't agree with my ideas and opinions.
Yes, there are the same topics being repeated over and over again, often started by people who are just beginning their vacuum tube journey. This is a good thing because it shows that there are new people joining the vacuum tube hobby. We need this in order to grow. As long as this forum remains a friendly place to ask what may appear to some as a dumb question, we won't scare the newbies off. Electronics is a hard enough hobby to learn, newbies (and many veterans) need all the help that they can get.
In this hobby there will always be different opinions. This is the first forum that I have visited where I actually signed up to participate because it seemed a refreshing change from some of the other forums where "flame wars" would errupt over a users choice of a particular $200 power cord.
Even though I slept through physics class, I understand that nothing (including electrons) travel at infinite speed, and that there is a definite, and measureable transit time. This is indeed a fact. There are opinions as to whether it would make an audible difference, and on this topic I remain neutral.
I still stand by the goals stated on my web site. We do need some more innovation in this hobby, or there won't be any new designs. The PowerDrive circuit is definitely a hybrid design. At the time I did that web page, I believed that the combination of CCS and mosfet follower to be unique. I am an engineer by trade, and I am choosing the best components for the job, whether they are tube or solid state. As with most engineering decisions this is based on my opinion not fact. You, or any reader is free to use the design or ignore it. My "mission" is to present these ideas in places where others can see them and use them if they so choose. There are other designs on my site that are "pure tube". I will add more when I get the time to update the site.
Yes, I agree that there are plenty of tubes out there that cost less than the 45 and 845 that are capable of great sound. I have a warehouse full of old tubes, which I am slowly sorting through and testing to find out which ones have good audio potential. It happens that I started with the 45, and the 845 because I had some, and they have a good reputation. They do give great sound, and now that I have established a reference, I have something to compare other tubes to.
One of the great things about this forum is that it is two way. I was asked about 6AV5's in another thread. Since I had some in the warehouse, I got a pair, hooked them up, compared them to other triode strapped pentodes, and was surprized by the sound that they put out. I shared the results with the participants of that thread, and they will eventually wind up on the web site. I would have likely not tried those tubes if it wasn't for this forum. Another thread got me to try 807's. That experiment was about to get underway when the hurricane struck, and all experiments have been put on hold since. Other threads have prompted future experiments that will be documented and published.
Again, I want to apologize if any one out there took my comments as an insult. I don't believe that any "insults" were intentional in this entire thread (certainly not my intention), just the differences in expression that are inevitable when dealing with an audience of a diverse cultural and technical background. I don't claim to be a technical wizard, just an average engineer who likes to experiment, and is not afraid to blow up a few parts. I intend to continue to share my experiences with anyone who can benefit by them.
Up until now I have found this forum remarkably free of the "verbal warfare" that is so common on other forums, and I hope that this one does not degenerate to a place where I must "do some homework" and investigate my readers, and potential readers, before posting for fear that someone won't agree with my ideas and opinions.
Yes, there are the same topics being repeated over and over again, often started by people who are just beginning their vacuum tube journey. This is a good thing because it shows that there are new people joining the vacuum tube hobby. We need this in order to grow. As long as this forum remains a friendly place to ask what may appear to some as a dumb question, we won't scare the newbies off. Electronics is a hard enough hobby to learn, newbies (and many veterans) need all the help that they can get.
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