And how does using tubes save you a fortune? Do tubes have similar characteristics like a transformer, whereas they output a different voltage then input?
No, no, no. Nothing about tubes saves you a fortune. Tubes are expensive compared to transistors/chips. The power supplies are expensive. The chassis building is expensive. Those output transformers are expensive.
BUT I like to build a tube audio amplier because:
1. Even today they are the most linear amplifying devices ever made.
2. That means reasonable amps can be made with very simple circuits.
3. They run nice and hot.
4. They glow when operating.
5. They use impressively high voltages.
6. They are nice and big to work with.
7. They are pretty hard to accidently destroy when experimenting.
8. You can look inside and almost see how they work.
Yeah, I know not much of that is a technical advantage over tranies but that's just me. Note: I don't include any nonsense about the superior "tube sound" in my list. Although if you ever build such a thing you will find yourself starting to believe it as well:)
Now, a typical tube is a power amplifying device. So not like a transformer. The characteristics of a tube are more like those of a FET. The current flowing through the load, anode to cathode, is controlled by the voltage on the grid input.
Of course the voltage swings on the output can be much bigger than those on the input so you have a voltage gain device. Or you could have a voltage follower configuration purely for current gain. Much like you can to with FETs.
BUT the currents we are dealing with are much less than can achieved with transistors so your final amplifier stage may well have hundreds of volts swing on the output only capable of driving 10s of milliamps. Enter the output transformer to convert that to a low voltage swing and high current to drive speakers.
Or in a hybrid amp the voltage gain of the tube stage can be a lot less, which means it can work in a very linear range of its characteristics, the MOSFET stage just follows that voltage and delivers the reqired current drive for the speakers.
Oh I forgot:
9. You don't need any printed circuits to build tube gear. Just bolt everything down to chassis and connect everything up with flying leads.
I'm still searching for that perfect synergy between the unique c.apabilities of the Propeller and of triodes to build some project that can't easily be done any other way. Then we will have a truely high voltage Propeller board!
Thanks for taking the time to explain that all to me. I certainly appreciate it.
I'm still searching for that perfect synergy between the unique c.apabilities of the Propeller and of triodes to build some project that can't easily be done any other way. Then we will have a truely high voltage Propeller board!
I think it just occured to me. That ultimate PropTube project.
One of the unique features of the Prop is it's video capabilities.
Well, traditionally video was displayed on what? Yes, that's right, tubes.
Just so happens that somewhere I have a big old round CRT as used in early radar displays on aircraft and later adopted by hobbiests to build televisions. Still any old scope tube would do.
Have the Prop generate the video and the scan lines and a few triodes drive the tube, bingo nice old green screen text display. Or perhaps vector graphics for that authentic radar look.
Prop then still has cogs leftover to do whatever you want.
N.B. That tube of mine sits unused for ages due to the tequitement of 1000 volts to light it up!
I know that feeling all to well. And to make matters worse, I now have deadlines which makes it 10 times as bad. Instead of being "want to do", they have become "need to do" projects.
My first electronics projects were with tubes. Was the early 80's too, LOL!! Loved 'em, and still do. Made a nice power supply for the older speakers that used electro-magnets to operate, along with some minor league oscillators, etc... And one crystal reference oscillator for my tube xmit/recv combo, I was running at the time. (.5KW BTW! Awesome, as it worked on the AM band, and yes, I did it too. The joys of being a kid.)
The fun part was the mechanical needs. Making a sheet metal enclosure, mounting sockets, and bus strips, then the wiring. Now, with everything so small, me sometimes using a lens to solder with, I often think back to the larger scale of things...
And come on folks! They glow. That's just cool on a whole lot of basic levels.
Re: Better sound.
Well, all I know is good, tube audio amps have a nice, "warm" sound. Couple those with a good stylus, and "imaging" on higher quality stereo recordings is excellent. Probably not better though, just a great sound, which counts for a lot in audio, where simple gratification is concerned. It has taken me a while to realize, but audio isn't often about perfect. I think we can do that easily enough. It is all about the "right" flaws that resonate with people and their particular tastes in sound.
I actually prefer old school AM radio on tube gear too. Often those circuits were designed with a nice bandwidth, and they had a smoother roll-off too, not the brick wall type IF filters seen today. The downside, of course, is increased sensitivity to noise and adjacent stations. The upside is a great reproduction of the human voice. Few things sound "better" than a high quality AM station doing voice, received on a tube radio meant to exploit the medium. That Zenith tower had two bandwidth options, narrow (3Khz or so) and wide (8Khz or so), with a few "tone" options as well. (Flat, bass emphasis, bass and treble emphasis) That was coupled with a great passive EQ, consisting of a cone behind the loudspeaker, dual cone, 12" or so, with a smaller 3" one inside, where you could pull and push this device that shaped the interior of the cone. Put the radio in a corner, or along a wall, then vary that to get a good resonance in the lower audio frequencies, and the radio would fill the room nicely, the sound being mono, but with a great, warm, "presence" great to listen to.
Re: CRT
That would be a great project! At some point, I may ask about that one here. Wouldn't mind using my scope for a raster at times. It's got 4 channels. Maybe overlay wave displays with either vectors, or a simple raster for all in one debug, measure display. There have been a few projects out there doing similar things. Seems quite handy to me.
Tubes are, of course, alive and well in the guitar amplifier business. And there it's got nothing to do with nostalgia or imagined "better" sound, it's simply that tubes distort the signal in a totally different way from solid state amplifiers. Different harmonics. And the tubes start "breaking up" the signal in a very nice way as the level increases. You can't get the anything like the same sound with solid state amplifiers, instead you can try to model the tube amplifier in a digital signal processor/computer. Modelling can sound good, but it doesn't sound the same.
I am a pretty easy going guy most of the time, and it really doesn't bother me that your remembrances have absolutely nothing to contribute to my given topic
I found your trip down memory lane quite interesting. In fact, I am glad that you and others can feel comfortable talking about any topic in my threads, even if it isn't on target. And I mean that sincerely.
Digression will always be open to a thread I start without any offense to me, however it may offend the forum police, but who cares
My father is long past for many years now, but he was radio and tv enthusiast many years ago. He was always messing with tubes in the tv and radio, as I remember, he even had a nicer tester for the tubes. I don't remember what happened to the tester, but I am sure there are many books still lingering around that pertain to the subject. Anyhow, you guys brought back some fond memories of my father.
When others do it, I always read with interest. And for me personally, if a thread I'm into, or have authored weaves off into some other place, another one can always be started. No worries. It's never at issue, because the desired state can always be captured, re-posted and continued easily enough. Not everybody rolls that way however, which is why I will sometimes tag one the way I did.
Honestly, I think it all comes down to value added. Where there isn't a value add, or a loss, it's worth policing that. Good for everybody. That too is why I will tag it sometimes, wanting to value add by making it clear it is a digression, and there are forms for that, when communicated, make sense. For me, one value add is simply getting to know others here. That's worth a lot, simply because community helps the hobby. Don't know about you guys, but there are not many people in my life that really appreciate this stuff. So I can come here, toss it about with friends, and all is good. Value added, IMHO. (done in moderation of course)
Edit: Well, higher voltage boards might have some applicability with tubes! I know, a stretch, but there it is. More realistically, I'm thinking about doing some very basic automation, 110V style, timers and such. I'm reading the higher voltage discussions with interest, just FYI.
Another Edit: I love radio. Always have. My Grandfather was the influence there. Glad to share some resonance with you on that Bruce. To me, radio is one of the very core, enabling technologies. A ton has been built on it, and it was the very first technology that "connected" people in far away places. Magic.
I am a pretty easy going guy most of the time, and it really doesn't bother me that your remembrances have absolutely nothing to contribute to my given topic
I found your trip down memory lane quite interesting. In fact, I am glad that you and others can feel comfortable talking about any topic in my threads, even if it isn't on target. And I mean that sincerely.
Digression will always be open to a thread I start without any offense to me, however it may offend the forum police, but who cares
Bruce
The joys of social media. Kinda like some of the groups that form at things like Interop or a training session..... My favorite key in many forums is either the delete key, or the next key.
@Clusso99
I would differ with your lecturer; the pilot light in an FET does exist and generally manifests itself immediately prior to the rapid ejection in gaseous form of the various internal structures of the device. Sometimes in a rather spectacular pyrotechnic display.
Comments
And how does using tubes save you a fortune? Do tubes have similar characteristics like a transformer, whereas they output a different voltage then input?
Bruce
BUT I like to build a tube audio amplier because:
1. Even today they are the most linear amplifying devices ever made.
2. That means reasonable amps can be made with very simple circuits.
3. They run nice and hot.
4. They glow when operating.
5. They use impressively high voltages.
6. They are nice and big to work with.
7. They are pretty hard to accidently destroy when experimenting.
8. You can look inside and almost see how they work.
Yeah, I know not much of that is a technical advantage over tranies but that's just me. Note: I don't include any nonsense about the superior "tube sound" in my list. Although if you ever build such a thing you will find yourself starting to believe it as well:)
Now, a typical tube is a power amplifying device. So not like a transformer. The characteristics of a tube are more like those of a FET. The current flowing through the load, anode to cathode, is controlled by the voltage on the grid input.
Of course the voltage swings on the output can be much bigger than those on the input so you have a voltage gain device. Or you could have a voltage follower configuration purely for current gain. Much like you can to with FETs.
BUT the currents we are dealing with are much less than can achieved with transistors so your final amplifier stage may well have hundreds of volts swing on the output only capable of driving 10s of milliamps. Enter the output transformer to convert that to a low voltage swing and high current to drive speakers.
Or in a hybrid amp the voltage gain of the tube stage can be a lot less, which means it can work in a very linear range of its characteristics, the MOSFET stage just follows that voltage and delivers the reqired current drive for the speakers.
9. You don't need any printed circuits to build tube gear. Just bolt everything down to chassis and connect everything up with flying leads.
I'm still searching for that perfect synergy between the unique c.apabilities of the Propeller and of triodes to build some project that can't easily be done any other way. Then we will have a truely high voltage Propeller board!
Thanks for taking the time to explain that all to me. I certainly appreciate it.
Bruce
One of the unique features of the Prop is it's video capabilities.
Well, traditionally video was displayed on what? Yes, that's right, tubes.
Just so happens that somewhere I have a big old round CRT as used in early radar displays on aircraft and later adopted by hobbiests to build televisions. Still any old scope tube would do.
Have the Prop generate the video and the scan lines and a few triodes drive the tube, bingo nice old green screen text display. Or perhaps vector graphics for that authentic radar look.
Prop then still has cogs leftover to do whatever you want.
N.B. That tube of mine sits unused for ages due to the tequitement of 1000 volts to light it up!
Sounds cool to me. Go for it, but keep us posted.
Bruce
I know that feeling all to well. And to make matters worse, I now have deadlines which makes it 10 times as bad. Instead of being "want to do", they have become "need to do" projects.
Bruce
So, how about using FETs and just add some orange leds???
Of course, you are in Finland where it is very cold, so I can understand that you want your electronics to create a "warm" surrounding!
My first electronics projects were with tubes. Was the early 80's too, LOL!! Loved 'em, and still do. Made a nice power supply for the older speakers that used electro-magnets to operate, along with some minor league oscillators, etc... And one crystal reference oscillator for my tube xmit/recv combo, I was running at the time. (.5KW BTW! Awesome, as it worked on the AM band, and yes, I did it too. The joys of being a kid.)
The fun part was the mechanical needs. Making a sheet metal enclosure, mounting sockets, and bus strips, then the wiring. Now, with everything so small, me sometimes using a lens to solder with, I often think back to the larger scale of things...
And come on folks! They glow. That's just cool on a whole lot of basic levels.
Re: Better sound.
Well, all I know is good, tube audio amps have a nice, "warm" sound. Couple those with a good stylus, and "imaging" on higher quality stereo recordings is excellent. Probably not better though, just a great sound, which counts for a lot in audio, where simple gratification is concerned. It has taken me a while to realize, but audio isn't often about perfect. I think we can do that easily enough. It is all about the "right" flaws that resonate with people and their particular tastes in sound.
I actually prefer old school AM radio on tube gear too. Often those circuits were designed with a nice bandwidth, and they had a smoother roll-off too, not the brick wall type IF filters seen today. The downside, of course, is increased sensitivity to noise and adjacent stations. The upside is a great reproduction of the human voice. Few things sound "better" than a high quality AM station doing voice, received on a tube radio meant to exploit the medium. That Zenith tower had two bandwidth options, narrow (3Khz or so) and wide (8Khz or so), with a few "tone" options as well. (Flat, bass emphasis, bass and treble emphasis) That was coupled with a great passive EQ, consisting of a cone behind the loudspeaker, dual cone, 12" or so, with a smaller 3" one inside, where you could pull and push this device that shaped the interior of the cone. Put the radio in a corner, or along a wall, then vary that to get a good resonance in the lower audio frequencies, and the radio would fill the room nicely, the sound being mono, but with a great, warm, "presence" great to listen to.
Re: CRT
That would be a great project! At some point, I may ask about that one here. Wouldn't mind using my scope for a raster at times. It's got 4 channels. Maybe overlay wave displays with either vectors, or a simple raster for all in one debug, measure display. There have been a few projects out there doing similar things. Seems quite handy to me.
Digression mode = 0
-Tor (my five-watt'er goes to 11)
I am a pretty easy going guy most of the time, and it really doesn't bother me that your remembrances have absolutely nothing to contribute to my given topic
I found your trip down memory lane quite interesting. In fact, I am glad that you and others can feel comfortable talking about any topic in my threads, even if it isn't on target. And I mean that sincerely.
Digression will always be open to a thread I start without any offense to me, however it may offend the forum police, but who cares
Bruce
My father is long past for many years now, but he was radio and tv enthusiast many years ago. He was always messing with tubes in the tv and radio, as I remember, he even had a nicer tester for the tubes. I don't remember what happened to the tester, but I am sure there are many books still lingering around that pertain to the subject. Anyhow, you guys brought back some fond memories of my father.
Cheers:)
Bruce
When others do it, I always read with interest. And for me personally, if a thread I'm into, or have authored weaves off into some other place, another one can always be started. No worries. It's never at issue, because the desired state can always be captured, re-posted and continued easily enough. Not everybody rolls that way however, which is why I will sometimes tag one the way I did.
Honestly, I think it all comes down to value added. Where there isn't a value add, or a loss, it's worth policing that. Good for everybody. That too is why I will tag it sometimes, wanting to value add by making it clear it is a digression, and there are forms for that, when communicated, make sense. For me, one value add is simply getting to know others here. That's worth a lot, simply because community helps the hobby. Don't know about you guys, but there are not many people in my life that really appreciate this stuff. So I can come here, toss it about with friends, and all is good. Value added, IMHO. (done in moderation of course)
Edit: Well, higher voltage boards might have some applicability with tubes! I know, a stretch, but there it is. More realistically, I'm thinking about doing some very basic automation, 110V style, timers and such. I'm reading the higher voltage discussions with interest, just FYI.
Another Edit: I love radio. Always have. My Grandfather was the influence there. Glad to share some resonance with you on that Bruce. To me, radio is one of the very core, enabling technologies. A ton has been built on it, and it was the very first technology that "connected" people in far away places. Magic.
The joys of social media. Kinda like some of the groups that form at things like Interop or a training session..... My favorite key in many forums is either the delete key, or the next key.
@Clusso99
I would differ with your lecturer; the pilot light in an FET does exist and generally manifests itself immediately prior to the rapid ejection in gaseous form of the various internal structures of the device. Sometimes in a rather spectacular pyrotechnic display.
Frank