Ask Slashdot: How Do You Build Your Own Vacuum Tubes? 275
Could you beat wireless headphones by creating your own DIY home audio system? Two weeks ago one Slashdot commenter argued, "to have good audio that is truly yours and something to be proud of, you need to make your own vacuum tube amplifier and then use it to power real electrostatic headphones over a wire." And now long-time Slashdot reader mallyn is stepping up to the challenge:
I want to try to make my own vacuum tubes. Is there anyone here who has tried DIY vacuum tubes (or valves, to you Europeans)? I need help getting started -- how to put together the vacuum plumbing system; how to make a glass lathe; what metals to use for the elements (grid, plate, etc). If this is not the correct forum, can anyone please gently shove me into the correct direction? It needs to be online as my physical location (Bellingham, Washington) is too far away from the university labs where this type of work is likely to be done.
Slashdot's covered the "tubes vs. transistors" debate before, but has anyone actually tried to homebrew their own? Leave your best answers in the comments. How do you build your own vacuum tubes?
Slashdot's covered the "tubes vs. transistors" debate before, but has anyone actually tried to homebrew their own? Leave your best answers in the comments. How do you build your own vacuum tubes?
Covered in the past. (Score:5, Informative)
Here's a good one with links to more: http://hackaday.com/2016/05/04... [hackaday.com]
Re:Covered in the past. (Score:5, Informative)
And here's another: http://hackaday.com/2014/11/21... [hackaday.com]
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They do throw some heat, they are far from fragile (otherwise every aircraft flight would be a throw of the dice, as there is no s
No no no. (Score:5, Interesting)
You don't need vacuum tubes. That's such a horrible audio myth. They glow in the dark and look nice. Aside from that, they produce more distortion, more noise, use more power, are more fragile, and have shorter lifetimes than solid state electronics. They do not sound better, given $X spent on whatever, presuming some reasonable amount of tech is returned per dollar.
OTOH, if you just want to make vacuum tubes because.... you want to make vacuum tunes... have at it :)
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Re:No no no. (Score:4, Interesting)
Of course, modern solid state amplifiers aren't particularly power limited (at least if you have the cash) and should never be driven into distortion. Effects pedals give you whatever distortion you want and have the advantage that you can turn the amplifier some level other than 11 and you still have the distortion you like.
Re:No no no. (Score:5, Informative)
Of course, modern solid state amplifiers aren't particularly power limited (at least if you have the cash) and should never be driven into distortion. Effects pedals give you whatever distortion you want and have the advantage that you can turn the amplifier some level other than 11 and you still have the distortion you like.
As a pro-level guitarist for 4+ decades and who also has been designing & building tube guitar amplifiers for nearly as long, I have to disagree.
Distortion type effects pedals are attempts to imitate what goes on in a tube guitar amplifier being pushed to (and past) it's limits and some come close (and many more close enough for the average local artist/band in bar/small-gig venues) but it does not sound nor 'feel' the same to play through for a good guitar player.
Nearly all the flagship lines of the major guitar amplifier manufacturers are tube amps. Most pro-level concert/festival guitar amplifier backlines are tube amplifiers. Fender Twin Reverbs, Super Reverbs, and Marshall amplifiers (often vintage '60s/'70s era) are the vast majority of venue-owned backline kit provided for touring acts (and usually specified by the artist/band in the performance contract 'riders' section) at most large venues.
As to making a home-brew vacuum tube, it is doable but not practical. To get predictable performance mechanical tolerances must be exacting and the materials used in commercial tubes are rather exotic and difficult (if not impossible to come close to) for a home-brew vacuum tube maker. What you end up doing is making a tube using 'best guesses' and test/measure the tube's operational parameters and design the circuit around those parameters, rather than the other way around.
The other problem with the inability to make tubes with fairly consistent and predictable performance and operational parameters is that it makes building things like the typical push-pull 2 or 4 tube Class AB1/AB2 power amplifier extremely difficult, as the tubes must be fairly close in there operational parameters or the unbalanced circuit will likely destroy the tube(s) of one side that conduct the most current. It would also be necessary to custom-wind output transformers to whatever plate impedance the tube(s) happened to exhibit
If you love vacuum tubes and spending exorbitant amounts of time & money mucking about with molten glass and exotic metals for fun, have at it. Just don't expect to build the equivalent of a McIntosh MC30 or a 100-watt Marshall using them.
There is an amazing amount of exacting engineering, sophisticated manufacturing processes/techniques, and exotic materials science in the old commercial vacuum tubes even by today's standards and is pretty much impractical and beyond the means for the vast majority of private experimenters to reproduce in a home shop.
Strat
Re:No no no. (Score:5, Informative)
Your good advice is useless. (Score:4, Insightful)
As to making a home-brew vacuum tube, it is doable but not practical. To get predictable performance mechanical tolerances must be exacting and the materials used in commercial tubes are rather exotic and difficult (if not impossible to come close to) for a home-brew vacuum tube maker. What you end up doing is making a tube using 'best guesses' and test/measure the tube's operational parameters and design the circuit around those parameters, rather than the other way around.
There is an amazing amount of exacting engineering, sophisticated manufacturing processes/techniques, and exotic materials science in the old commercial vacuum tubes even by today's standards and is pretty much impractical and beyond the means for the vast majority of private experimenters to reproduce in a home shop.
Strat
I've lived long enough to know that when some dude says "I want to build my own vacuum tubes" that he's not interested in hearing how unrealistic it is.
Re:No no no. (Score:5, Interesting)
The reason real guitarists prefer tubes is because of the distortion. Solid state just doesn't compare.
Well these days they do compare. Humans can't distinguish between an amp modeled on (for example) a Kemper modeling amp and the tube amp it modeled.
A few years ago it was not the case, but DSP always wins in the end.
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As a former guitarist, i can tell you this: is not so much about the sound, but how tube amps react to ones playing. The old Line 6 stuff, f.ex, already sounded fantastic on recordings back in 1999 but didn't quite "feel" like the real thing.
Having said that: i haven't tried the latest state-of-the-art offerings from Kemper et al, but i hear this has improved a lot since then.
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The reason real guitarists prefer tubes is because of the distortion.
This is not entirely true. The dynamic known as "pick attack" is also something which solid state amplifier and DSP cannot reproduce with any level of accuracy.
Interesting, but Kemper disagrees with you. Their amps even have a "pick attack" knob.
Solid state just doesn't compare.
Solid state does many things well, but it has its own niche.
Well these days they do compare. Humans can't distinguish between an amp modeled on (for example) a Kemper modeling amp and the tube amp it modeled. A few years ago it was not the case, but DSP always wins in the end.
Bullshit.
I call bullshit on your bullshit :)
Just watch the following video, where two experienced guitarists do a blind test: https://www.youtube.com/watch?... [youtube.com]
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But but but... you obviously haven't listened to hand crafted artisanal vacuum tubes using hand blown glass and mastodon hair wrapped with isometrically pure tungsten. The tungsten caresses the electrons in a way that's just not possible modern day transistors.
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they produce more distortion
Only in circuits where they are driven extremely hard...or guitar amps where a tube will naturally do what takes ton of DSP
more noise
again...depends on what type of circuit you're using and if you're using the suitable tube. Stick a 6AU6 in your audio stage and it's going to get noisy.
use more power
You have me here. Thermionic Emission requires the heat.
are more fragile
Toss-Up. Drop a tube and it'll likely break depending how and what it hits. On the flipside; there are ways a transistor will fail that a tube won't care about. My tubes aren't goi
Re:No no no. (Score:5, Informative)
You cannot measure or quantify sound quality.
Yes you can. Hi-Fi equipment is suppose to *reproduce* the original as accurately as possible. This is something you can and people do measure. Hence the name Hi-Fi an abbreviation of High Fidelity.
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This is better stated as "most people don't know what good sound reproduction actually sounds like". We certainly can measure sound quality. People like Amar Bose didn't ever publish specifications because the average listener prefers unreal bass (go listen to a live orchestra) and isn't too sensitive to distortion.
It gets worse with digital. We took a medium that could reproduce sound much better, and compressed it, taking away that advantage. All musical compression is designed to replace aliasing with no
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Sure you can, unless you believe in magic.
If the output waveforms are the same when plotted on an oscilloscope, then there is no difference between the amplifiers as far as sound quality is concerned.
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Re:No no no. (Score:5, Informative)
Actually that's not true, just ask a guitarist (and IAAG - I Am A Guitarist!)
Vacuum tubes create a noisy signal, but in a weird coincidence, they do it in a way that is pleasing to the ear. The clipping and distortion sounds "warm," and there's an added depth in the sound (harmonics) that you don't get via transistors -- unless you create circuits that mimic the behavior of a vacuum tube.
Metallica? Tube amps. John Mayer? Tube Amps. Clapton? Tube amps. BB King? Tube amps. Eric Johnson? Steve Vai? Garth Brooks? All tube amps.
Of course, much of the "tone" we guitarists revere comes from overdriven and abused guitar tubes -- cranking up the volume on the tube so that there's massive distortion and noise -- which again sounds pleasing to some people.
Now, it's one thing to overdrive a tube or change the bias on it to get a particular sound from your guitar, what about building a tube amp to just listen to music?
Well, I suspect this is essentially "remixing" songs. Adding a bit more depth, dirt, or warmth (from the noisy tube) might sound better but that's subjective, and it's all about personal preference.
So, sir, you might argue that you dislike what a noisy tube does to your signal, but you can't say some people won't perceive it as improved, as it's about personal taste.
Re:No no no. (Score:4, Interesting)
You're conflating two different purposes for an amplifier. An instrument amplifier is part of the instrument itself. The choice of that amplifier has a significance to the music that is trying to be produced. Implying that all those famous guitarists chose tube amps because they are better at something ignores all the solid state amps that are used by musicians too. They have a different sound, not good, not bad, just different. Both when run normally and when overdriven. The choice of an instrument amplifier is purely artistic.
Well, I suspect this is essentially "remixing" songs. Adding a bit more depth, dirt, or warmth (from the noisy tube) might sound better but that's subjective, and it's all about personal preference.
This irks me. It's like saying that the Mona Lisa is nice and all but it should have been painted with more yellow. The purpose of a hifi amplifier is to reproduce the small signal as faithfully as possible, and with as little distortion as possible. Every design aspect should be based on the output being nothing more than a larger input, any modification to the signal should have happened before this stage (either in the studio, or if you really feel like not listening to the music as the musician intended then with a pre-amp). In that regard an interesting combination is often a vacuum preamp followed by a solid state tube amp.
But really the parent was on the money with the physics behind it. Tubes produce a more pleasing sound than a typical Class AB push pull amplifier due to harmonic distortion being predominantly odd order rather than the even order in solid state amplifiers. However in terms of being able to faithfully reproduce a signal in a larger form they are blown away in every metric (except power consumption, the GP got that wrong) buy a well designed Class A solid-state amplifier.
Now personally I think the Mona Lisa is too small.
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I got that backwards. Tubes produce even-order distortion. Push-pull solid state amplifiers have almost zero even order distortion.
Read twice, post once.
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Just think of it as even harmonics, and it fits better into musical theory.
Obviously, what you really want to do is use amplifiers with sufficient power that they are never driven into distortion. And if you want distortion, get it from an effects pedal.
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This irks me. It's like saying that the Mona Lisa is nice and all but it should have been painted with more yellow.
::SNIP::
Now personally I think the Mona Lisa is too small.
The way art is presented (whether that's music through a hi fi stereo or a painting to the public) can change the way the art itself is perceived.
You might have no control over how much yellow Leonardo used for Mona, or how big he painted her, but you might put her under fluorescent or halogen lamps, or in sunlight (which will all add slightly different color casts to the painting). You might choose to display her behind a fresnel lens to make her bigger. Or you might put her on a white wall, or a black w
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The purpose of a hifi amplifier is to reproduce the small signal as faithfully as possible, and with as little distortion as possible.
Yes but...
I mean I agree and all, but older music often sounds better on old and objectively worse kit than newer music on the same kit. I think the reason for that is you simply couldn't make high power high linearity amplifiers cheaply until relatively recently, and musicians knew that mostly their music would be listened to on the kit of the day, so they wrote and mixe
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Actually that's not true, just ask a guitarist (and IAAG - I Am A Guitarist!)
Vacuum tubes create a noisy signal, but in a weird coincidence, they do it in a way that is pleasing to the ear. The clipping and distortion sounds "warm," and there's an added depth in the sound (harmonics) that you don't get via transistors....So, sir, you might argue that you dislike what a noisy tube does to your signal, but you can't say some people won't perceive it as improved, as it's about personal taste.
IAAP and Vacuum amps add a 'third harmonic distortion' to an input signal. Whilst this is desirable for a guitarist, for home listening it introduces distortion that I did not intend to be there when I produced your excellent performance. All that time I spent adjusting the attack and release on the compression to capture those really cool movements of your fingers on the strings are lost because a 'audiophile' decided that they knew better that the people who produced the music in the first place.
Transis
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I think the new class D amps eliminate even this issue, however they use more electricity.
It should be the reverse. Class A uses the most power (~20% efficient), Class AB about 60% and D comes in a little under 100% (~90%) or so because the semiconductors are acting as switches dissipating very little heat. The downside is that the high frequency switching can induce all manner of interference which will cause havoc if not properly dealt with.
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Not true. [idc-online.com] Breakup characteristics are measurably different between tubes and transistors.
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Spoken as someone who knows a little, but not enough about music engineering.
Tubes have been and are still used for ALL manner of instruments (including vocal) for "warming" sounds, saturation and creating distortion effects. The even harmonic distortion they produce when you overdrive are pleasing to the ear and can add an organic character to a recording that is otherwise lacking.
Different tubes produce different sounds so experimenting with your own would be interesting. For example: I remember replacin
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Instrument is the right word. But there's a key theory in your post:
In music it is quite often the IMPRECISION that makes the bland great.
That imprecision is an artistic choice. It should not be a listener's choice. The imprecision of instrument amplifiers are part of the instrument. The goal of a normal stereo amplifier should be the most precise reproduction of the artist's choices.
But I'm probably in the minority with this view given how many times I step into a hired car and find the first thing I need to do is drop the bass and treble back down to zero.
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"and have shorter lifetimes than solid state electronics."
Spoken like someone that never used W-grade (military) tubes in their life. Mine are still kicking in my 1978 Fender Super Reverb, from when my father bought them. That's almost 40 years. You got any solid state stuff that old, gramps?
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You're not using the original capacitors, are you? If so, some time with an ESR meter and the required replacements would help.
Yes, I definitely have solid-state electronics that old. Including test equipment. But most have been recapped.
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You don't need vacuum tubes. That's such a horrible audio myth
The summary doesn't say anything about sound quality. My guess is that he's using vacuum tubes because it's possible to 100% DIY a vacuum tube amplifier from off the shelf parts. If you try to build a solid state amp from scratch, you are probably going to need to get custom PCBs built and you'll get to test the steadiness of your hands as you try to solder tiny SMD chips.
Now, making the actual tubes seems a little overkill (is he also making his own transformers, resistors, wiring, etc?) but, if you want
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Re: No no no. (Score:2)
Vacuum tubes don't necessarily sound more accurate , but unless you run a recording studio you don't necessarily want accurate , which is why studio monitors don't necessarily make for good listening speakers. Valves however sound good and that's a result of their behaviour at high current. Transistor amplification hard clips at max power creating flat peaks that sound absolutely terrible, whereas Valves produce rounded clips with a degree of compression at the peaks. This has the psychoacoustic effect of
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... they produce more distortion... They do not sound better, given $X spent on whatever, presuming some reasonable amount of tech is returned per dollar.
This is simply not true; in fact, it's a line of BS almost as bad as the one that says thousand dollar cables will make your system sound magical. (BTW, something you hear is not necessarily true just because it's said by a bunch of engineers bathed in the fountain of 'knowledge' passed on by an earlier generation of engineers whose conclusions were 'helped' by marketing requirements).
First, let's look at the metric known as THD; it is calculated as the ratio between the total power of all harmonics and the
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more distortion
Metal fans consider that a feature, not a bug.
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and have shorter lifetimes than solid state electronics.
Going to dispute that one based on my own personal experience. I have a 1925 radio(can't remember who it was made by), beautiful piece of work. Maple case, cherry wood veneer, it is of course all tubes(mix of amplified tubes and non-amped), uses lead solder, has the wiring diagram on the back of the case written in pencil, the person putting it together was smart enough to use wire colours in particular orders and is signed by the person who built it. That in itself is unusual, since a lot of the people
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A lot of old technology works better than the new stuff. However you will need to be an expert at it to get it that way.
For example the adjustable focus on camera vs the auto focus. Pros use the adjustable focus so they capture the picture just as they want it. For the average person who gets the same camera they will be taking a lot of blurry pictures with an expensive camera. And would be taking better pictures with an auto focus camera.
The same with tubes. A pro can make them sound warm and clear, wh
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So they waste your money sticking vacuum tubes in the circuit, then use solid state amps in the actual headphones. I'll stick with my original Koss ESP-9 electrostatics - they've stood the test of time without the vacuum tubes raising from the interior gimmick.
Yeah, no (Score:5, Informative)
Okay, we need to discuss classic amplification (IOW, not digital) and tube vs. transistor distortion. Applies to all audio reproduction systems - receivers, preamps, amps, headphone amps.
When run entirely in their linear range, which is to say, in class A amplification, where very expensive and/or high end analog musical system designs sometimes run, analog devices, be they tubes, fets or bipolar transistors, all follow the input signal faithfully, plus or minus total system noise and phase shifts -- no "warmth" or other characteristics are inherent in even a half-decent design, unless you add it yourself with tone controls or the like. *NONE*. For the record, tubes make the most noise, bipolar transistors next, various field effect transistor types the least. Analog integrated circuits tend to use bipolars and/or FETs; look the specific IC up to see, there's no telling otherwise.
So what you want, ideally, is the very minimum of distortion, noise, and as close to perfect signal reproduction as you can get. What goes in equals, as closely as possible, what comes out. But class A is an expensive and power-hungry way to do anything. So most reasonably priced tube and transistor linear amplifiers tend to run in class AB, which uses two devices or sets of devices at the high levek output, where one set amplifies the negative excursions of the signal, the other the positive set. The idea is that the devices are slightly on all the time, and when they begin to amplify their part of the signal, there won't be much distortion from moving into the linear part of their amplification curve from the non-linear, off, part, because the device isn't switching from off to on, it was already on. This works really well, and some very high end tube and transistor equipment works this way. Uses a little extra power, but it's a great compromise.
So what's different in a useful and interesting way between tubes and transistors? Well, when a tube is pushed into its nonlinear range, the gain transfer curve bends over comparatively smoothly so that what would be a sharply clipped (squared off) signal in a device like a bipolar transistor, turns first into a compressed signal, and even later down the curve, begins to evidence harmonic and other distortion that somewhat resembles that produce by hard clipping, but has, because of that still-somewhat-gentle curve, an entirely different set of dominant harmonics as compared to, for instance, a bipolar transistor at or near saturation. So the distortion, when the system is run so hard it distorts, sounds quite different.
That characteristic is why (knowledgeable) musicians who use distortion as a tonal tool often choose tubes; specifically because these musicians *do* run the tubes out of the linear area of the transfer curve, and the result is interesting -- and often pleasing. When the distortion is the result of a transfer curve that abruptly goes from highly linear to highly nonlinear, as is the case with bipolar devices, the result is most unpleasant. Edgy. Sharp. Dissonant. It isn't very often that such a thing is well received in a musical performance.
However, this choice does not *ever* hold true for a musical reproduction system based on tubes that isn't running in a range that will distort the music. You'd have to turn it up so far that one or more elements of the preamp or power amp is pushed past the linear part of its transfer curve, and then all of the music distorts -- and that's not a "warm" sound, that's a "hey, your system sounds awful, turn that thing down before I puke" sound.
So, for example, if I get out my Les Paul or my Strat and plug it into a tube amp and turn that bizatch up, I'm doing so because the amp's distortion is going to very significantly color the reproduction of what I play. I'm going to adjust the amp specifically so I *get* distortion. It'll sound fabulous. I'll get feedback, there will be awesome weirdnesses when I hit harmonics on my strings, pick and fretting artifacts will sound very different,
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Awesome post, thanks. What about digital emulations of the analog effects? I implemented some filters for my guitar when I studied signal processing, and it was so much fun, I wish I had more time to kid around with it.
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You're welcome.
You can emulate anything, pretty much. You need a high enough sample rate, enough bits, and a complete understanding of what the effect does, and how it is controlled, if indeed it is.
If you skimp, you'll get... something else other than the original effect.
I write signal processing software pretty much every day. Here's my current obsession. [fyngyrz.com]
Re:Yeah, no (Score:4, Interesting)
Emulation has come so far in the last 10 years that Geddy Lee of Rush got rid of his amps and went direct into the mixing board through an effects board. So much room was saved on stage they filled the spot with chicken (roasters or washers and dryers if it was laundry day for the tour)
Re:Yeah, no (Score:4, Interesting)
There are actually apps that let you run all kinds of emulations of classic amps and pedals. AmpKit is one that comes to the top of my head, but there's others.
Just plug an electric into your computer (using a USB interface) and you can push a button and sound like ZZ Top, or any number of presents.
You can also buy pedals that do this. (Just google Fractal Audio). Then plug right into the PA.
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Yeah right, maybe ZZ Top could could like sound ZZ Top playing through an emulator to us, less likely to ZZ Top and You definitely wouldn't sound like ZZ Top, even playing on ZZ Top's rig. 80% of the magic is in the guitarists fingers, not the rig and not the guitar.
Who really cares anyway, the kids today take a CD of some pop-star, with mediocre quality at best, rip it to a lossey MP3, load it on a smartphone and listen through overpriced headphone and think they are hearing music.
Re:Yeah, no (Score:5, Interesting)
https://www.youtube.com/watch?... [youtube.com]
https://www.youtube.com/watch?... [youtube.com]
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Excellent informative post and explained very well.
I've tried explaining this to people before but you have expressed it so well I'm cutting and pasting that into my collection of "here's one I prepared earlier" answers!
Have you much insight into T-class (tripath) amps. I've heard that T-amps produce the least distortion of all popular amplifier designs, are cheap to make and cheap to drive. Any wisdom here?
https://en.wikipedia.org/wiki/... [wikipedia.org]
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A T class a is basicaly a class AB amp, with a class D powersupply.
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I think some of the confusion may be a holdover from way back when we were transitioning from tubes to transistors. What you said is true for good reproduction amps. But most people have/had mediocre amplifiers. They definitely don't have enough headroom to cover transients and the typical home stereo doesn't even have enough to not distort horribly when turned all the way up. Under those conditions, a mediocre tube amp would sound better than a mediocre transistor amp of that time.
None of that applies to c
Poleaxed by your response (Score:3)
But have you purchased your own telephone pole? [wsj.com]
NO? Bloody amateur.
Re:Yeah, no (Score:5, Informative)
Wow! Exactly what I've learned in fifty years of audio/broadcast production. I wish I had written it; I certainly wanted to.
I would give the speakers/headphones more emphasis, however. No matter how expensive your rig is, speakers as good will be more. Much more. Including the speakers (especially cheaply-made and poorly designed) in the system evasluation gives an edge to the way bipolar transistors handle transients or square waves. A high power-to-cone mass speaker will follow the sharply cut off curve of a transistor well enough to make a listener's ears bleed, that's true, but a low power-to cone mass cheapie will not; its physics actually complements the transistor's characteristics by not following its sharp peak, but taking its lazy time returning to its accurate excursion limit. In effect, a cheap speaker "smooths' the spikey output of an overdriven bipolar transistor or IC.
But wait, there's more! Psychology is the number one influence. We like what we are used to hearing. We get used to good audio over time, and we become more selective. Or, if we have only heard distortion all our lives, we get to miss bad production if it is absent.
Re:Yeah, no (Score:5, Interesting)
Re: Yeah, no (Score:3, Informative)
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32bit systems are a joke. None of them have low enough noise. For high end systems the first 20 bits might be useful information , if you're lucky. After that the rest of thr bits are noise, and are, from a physics standpoint, hooked up to a gaussian random number generator.
Are you sure about that? If you use a 20 bit system, you're clipping the noise bits to "0", which won't necessarily be more accurate than letting them remain at their original value. Those bits don't go away--the system still deals with digital values, you've just limited it to fewer possible digital values. This is rounding, and I don't see why rounding away the noise is any more likely to round it in the right direction than wrong.
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The best headphones on the planet use vacuum tubes [youtube.com].
I don't listen to music on my iPhone, but I use a BT headset for driving. Are any of you butthurt Monster Cable audiophiles going to install a Sennheiser Orpheus in your car? Pictures please if you are.
Building Scientific Apparatus (Score:2)
This may well be overkill for your needs, and it's a bit pricey, but the book Building Scientific Apparatus [amazon.com] has been on my wish list for a while. It has chapters on working with glass, vacuum technoloy, charged-particle optics, and electronics, among others.
Sigh, too many projects (including a pair of novels to finish) and not enough time.
Already been done: (Score:3)
https://www.youtube.com/watch?... [youtube.com]
https://www.youtube.com/watch?... [youtube.com]
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The tube is the easy part (Score:2)
you'll need a diffusion pump as a second stage to a regular pump
something like this
http://www.instructables.com/i... [instructables.com]
You will also have to coat the interior of the tube with some sort of getter to keep the vacuum.
and then there are the seals
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Apple pie from scratch (Score:2)
Other than the experience points, I can't see why you'd make your own tubes. Would you make your own transistors?
I've hand-wound guitar pickups and made a ribbon microphone from scratch. Fun stuff, but I could never approach the quality of a stock Fender pickup or Royer ribbon mic.
Sovtek still imports Rusdian tubes, right?
k.
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Would you make your own transistors?
Yes. If I could.
Humans pride themselves on learning a skill. Providing this skill is within reach and doesn't require super expensive industrial equipment why wouldn't you attempt to build something yourself?
Some people buy pre-made equipment.
Some people assemble equipment from pre-made modules.
Some people assemble modules using components and manufactured circuit boards.
Some people make their own circuit boards.
The rabbit hole is only limited by your ability to make something that is functionally suitable,
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What is stopping you is that you think you need ultrapurification and microscale fabrication. No. Remember that the first receiving diodes were semiconductors, and while some used germanium it was not unusual to just use a rusty razor blade and the graphite point of a pencil. There are lots of semiconductor materials available to you, and making a cat's whisker is not difficult. It won't be the best transistor in the world, but it will amplify.
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You can find practically any tube you might be looking for on Amazon.com, if you know the part number. Many of the same tubes you can find on the specialty sites that serve audio fetishists who "roll tubes" in their single-ended triode tube amps can be found for half the price on Amazon.
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I think people make tubes because a normal person can with some combination of money and effort - used vacuum pumps aren't that hard to rebuild. You could cheap out and use fixtures, but a reasonable quality glass lathe is something like $14k. It would be a relatively expensive hobby, but still cheaper than cars.
glass blowing (Score:2)
Of course, physics and engineering labs used to "make their own" vacuum tubes. But generally, they had skilled glass blowers on hand who could create vacuum-proof glassware for them. If you really want to try, you might consider starting with chemical glassware intended to be used with vacuums.
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Wire, glass, metal, and a big rocket (Score:2)
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Don't you have that backwards :-)
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Warmer? (Score:2)
Does it make it sound warmer? Is it warmer than these wooden standoffs ( 600.00 each ) I got to hold my oxygen-free digital cables off the floor ( a steal at 900 for 6ft )?
Why anyone would ever be interested in tubes. (Score:2)
Various rock musicians prefer tube amplifiers because the conventional tube circuits used since the 1950's, when driven far into distortion, emit even harmonics much more than odd harmonics. This is a perceptually more comfortable sound to the music listener.
Older transistor circuits (we're talking the 1970's) tended to emit odd harmonics.
Obviously you can make a transistor circuit that distorts with even harmonics. However, it is much better to use an amplifier of sufficient power that it is not driven int
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If you want distortion, use an effects pedal. Don't get it from your amplifier.
I'll pit my Dr. Z against your effects pedal anyday
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Sure but 1.3 KW is not "tremendous" power -- it's amateur range stuff. Broadcast AM stations go up to around 50kw, which is a "normal" for that application.
In the 30s and 40s, WLW in Nashville broadcast at 500KW. Radio Monte Carlo's transmitters currently put out 2x700KW in long wave and an even 1MW in medium wave. Russia's Taldom transmitter pumps out 2.5MW in long wave.
So I'd say anything over 10^8 watts is tremendous.
There are tubes that individually are rated in the MW range, like the 8974 power te
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I'm not a tube fan, but electrostatics? Sure! (Score:2)
Electrostatic speakers/phones aren't especially hard to make, but sourcing the materials can be difficult. You need ultra thin polyester film for the diaphragms, and some sort of weakly conductive coating (Licron or similar antistatic spray works well). You also need a method of stretching the diaphragm film tight and then gluing it while stretched. I invented a pneumatic stretcher almost 30 years ago when I was into all this stuff. 4693H contact adhesive will stick to the polyester (not much else will)
Great video (Score:2)
It's possible (Score:2)
It's possible to do, but you'll need a fair bit of gear and expect your first few batches to be defective or die soon after powering up.
There are lots of youtube videos that show how it's done, but many of them leave out critical bits of info. As a project in tech school my lab partner and I built a working vacuum tube (we all had to), but we had all the gear we needed and lots of instruction. Even then it was difficult to get t right, lots of failures and lots of "sort-of-working" tubes.
So it can be done,
Lightbulb (Score:2)
A vacuum tube is a lightbulb with extra electrodes. So he is a video of how to make a light bulb with glass. https://m.youtube.com/watch?v=... [youtube.com]
I make tubes! (Score:5, Informative)
Recommended book. (Score:2)
I want to give making my own valves a go, but first I've got to overhaul my vacuum pump, because it doesn't suck. (Well, I need at least 35torr, and it has trouble getting to 120torr.)
I've got this book and like it: Instruments of Amplification [amazon.co.uk].
It's not so much a howto guide as a recounting of "I did this, and this is how it worked". Useful tips on how to cut open bulbs and harvest filaments, how to drill glass, basics of vacuum working and lots else.
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Bloatware these days...
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the prices!! [thetubestore.com]. No wonder people want to roll their own...
Those may be "old stock" tubes which aren't made anymore. Since there's no new supply, the prices will be higher - when they're gone, they're gone for good.
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They are not made in the USA cause its a obsolete technology with no means to make a profit .... besides the question is about a 1 off project, not making a industry comeback, so quit being a knee jerk dipshit
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Even if you can do it, complying with the environmental regulations would bankrupt you. That's why vacuum tubes are manufactured in Russia and China, but not the US anymore.
Just what are you smoking? Vacuum tubes aren't made in the US anymore because there's no market for them and Russia and China are the only countries that can support manufacturing for a dead industry. There's nothing inherently bad in making a vacuum tube that would cause environmental regulations to become a limiting factor.
Tubes are still made here in the US.... (Score:3)
But generally only the exotic special purpose and transmitting types. The commodity 12AX7s and 6L6s for guitar amps are all made offshore, due to the low profit margins. The only audio types being made in the US are Western Electric 300B triodes, which are still being made in limited numbers for the high-$$$ audiophool market.
http://www.westernelectric.com... [westernelectric.com]
Other remaining US tube manufacturers include CPI/Eimac:
http://www.cpii.com/division.c... [cpii.com]
and MU, Inc. :
http://www.mu-inc.com/webstore... [mu-inc.com]
, who apparen
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Recycle, Recycle, Recycle. (Score:2)
Every light bulb or dead tube has multiple glass/Kovar bonded seals.
You can carefully break or melt them out and reuse them; large bulbs are good sources of large connections.
BTW, Neon electrodes are different; they are designed to hold mercury.
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Those are colored phospor cold-cathode tubes. They aren't as pretty as real neon tubes which get their color from an ionized gas, and I wish folks would not call them neon at all.
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Mercury is a bummer, but if you want bright colors, you want some mercury vapor in there as a charge carrier.
The fun gas is Helium; it's a beautiful orange color.
It's used as a cooling gas; one of the rules I learned was "If you see your equipment glowing bright orange, Don't open the door to the lab!" :)
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I like this idea. This way, your 3D printer can create absolutely nothing where it's useful to do that. :-)
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Ones that make nuclear accelerators or the emitter in any synchrotron, cyclotron, bevatron, etc. It's a big long vacuum tube.
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