Journey to the Center of a Tube
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- Опубликовано: 10 мар 2009
- Your host Robert Hull takes you on a journey to the center of a tube. You will be astounded at the beauty of this SED 6L6GC tube, so close you can almost touch it. From the outside glass to the deepest filament, see every element in vibrant color ... just please, refrain from feeding the electrons.
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I love how enthusiastic Rob is about electronics. He has really taught me alot :)
when i was younger, id always imagined blinking myself small and tiny, and wandering about inside the old tubes i found around in the family TVs and radio. Yes, ive taken a rear television cover off when i was about 5yrs. old. I took all of my toys and things apart. Usually, got it all back together. Back then when i was a child. Awesome video TY so much.
Pretty cool to see inside a tube. Quick note: mica isn't a rock, but a mineral. It's actually a group of minerals that are sheet silicates with Moh's hardnesses of 2-2.5.
Had a 1945 Stromberg Carlson field PA made for the navy. It was housed in a green ammo style box with latches around the center. Flipped it over to remove bottom and inside was the pristine circuits. Used a dynamo instead of a transformer. 12V in one armature and the other side was 600V on that armature ( commutator brushes like any motor). Another box the same size, roughly 18''x9''x9'' was the 12V & 8V battery supply for this amp. It had a 5.2ohm output transformer. 60 watts RMS.1 volume knob
Thanks for taking us inside the tube! Next you can take us to a tube factory so we can see how they are made?!?!?!?!
Robert Hull! A very helpful guy. I have a '96 Fender blues Deluxe. V1 and V2 JJ 12AX7, V3 JJ 12AT7, outputs SED 6l6GC. SED's are biased at 425v plate, and 32mA. Idle disapation is 45%.A very sweet combination. The high end of the SED's are smooth and sweet. My Tele' rings like a bell without harshness.
My experiences as a electronics technician for over 4 decades has taught me that TUBES ARE SWEET! They are tough under various situations like spikes , surges , Emp. , etc. That's why Rf transmitter , microwave devices use a MAGNATRON . Think of a Tube like Hercules /Arnold. Believe me I have seen during troubleshooting a Horizontal 15,757hz (scan freq) 6LF6. Horiz. Output tube with a grid screen problem of incorrect bias which caused over saturation of current from cathode to plate causing the tube to over heat /glow red. Found a open bias resistor that corrected the bias issue. The tube survived the overheating esp since the customer would run the set with such bias failure . Anyway mr. 6fl6 kicked ass. Transistors under such biasing situation will cause "avalanche " of the pnp/npn junctions. Avalanche directly leads to junction thermal runaway. ( leakage/dead short in the junction.) TUBES SOUND GREAT OVER SOLID STATE NO EXCEPTIONS! Thank you for reading. Ken
This was quite the teardown video! Nice camera work, editing, narrating and exceptional audio mix quality! Would love to learn more from whomever crafted this piece of media... =)
A very long time ago, my mother's first job out of HS was a tube assembler at Amperex in Hicksville. She was a perfectionist so she got HQ duty to build tubes used in ICBM's. Unfortunately, not Bugle Boy 12AX7's. If we had a crystal ball, we should have bought cases at a company discount, direct from Holland. It would have made up for the poor pay and conditions and the insulting pension for almost 25 years. Interesting to see the dis-assembly! Thanks!
Your mom had a cool job ...
+TubeDepot aaah ya mudder works in a tube factory,, sorry couldn't hep mysef
Awesome video and excellent explanation. Thanks for showing
You're video answered a lot of questions I had about tubes (known over here as valves), also, i enjoyed the music, really nice!
Extremely creative title!! Vacuum tubes are superior in power output circuits..to this day..noise reduction is awesome. When younger, I was technician.
Way cool. Thanks for explaning what each part is and what it does. Gave my 100 watt Mesa from the early 80's to my metalhead son. After I replaced the tubes and went over everything it sounded much better than when new. Wished I'd let him have a different unit.
After destroying vacume tubes back in the 60's and picking through the parts I have a whole new perspective. I think I'll get that old turntable out and................
Wow I am gonna call you, "Fire Fingers" for yanking that hot tube out of that Mesa Boogie! I though the getter was flashed with heat and a high freq inductive wand. I want to see you reassemble the tube. Philips had a great tube book with photos & drawings. I have one of the few copies in English. Pete Millet has it in Dutch (PDF download for free), & many more audio books/telco/misc, (mostly vacuum tube) including RCA Designer's manuals. There is even one with 3D diagrams, but no glasses.
Very nice presentation - well done!! Thank You
Thanks a lot for this video ! Very informative and satisfying ! Please put more of these !
Thank you so much..... What a wonderfull presentation...
I should have been asleep a long time ago. Instead I'm watching all your videos o.O
Killer video! Thanks for showing us how they work!
Amazing visualization ! Thanks for the great video!
very cool video...ingenius design behind tubes
This is so cool! Thanks so much for doing this!
The screen grid runs very hot, because it is absorbing some of the cathode current. It is coated with graphite, both to help cool it by improving infrared radiation, and to keep it from emitting secondary electrons (graphite is very good at this). This has nothing to do with "improving the tone".
The control grid is plated with gold, also to help prevent secondary emission. Gold gives a smoother surface than graphite, so it's better suited to the control grid.
Thank you , enjoyed the detailed journey.....amazing
Absolutely loved this video, I'll never look at my tubes the same way again!
Thanks
Awesome video!
Excellent video!
Wow, you are very knowledgable. Thanks for this great video!
This is FANTASTIC!
amazing video!
Fantastic vid. Thanks!!
Great video! Thanks for sharing!
(and Boogie on!)
Fascinating!
I always wondered how the tubes were assembled.
awesome video..
Nice illustraion, good work on the video. A few additions I might want to add, though:
The tabs that center the assembly in the envelope are most likely not made from aluminium. I am not 100% sure by the looks of it,
but solid aluminium does not lend itself very well to be used inside an vacuum environment due to the oxide layer on the surface.
It is used on anode coatings but this involves some processing on the pump to make that work.
Cooling fins on the grid are to keep the grid cool enough so it does not become an electron emitter itself. The proximity to the hot cathode and
the posibillity of barium migrating to the grid from the cathode coating can cause the grid to become able to emmit electrons as well which is not wanted.
The getter usually does not contain pure barium as this would be difficult to handle during production, instead it is usually an alloy of barium with other
metals such as aluminium and magnesium, both of which are not very good getter materials by themself but help to keep that alloy reasonably stable and workable.
Sometimes nitrogen compounds might be added to help with dispersion, I am not sure how common this is, though.
Sometimes there is an additional protective coating over that alloy to protect from moisture. When the getter is evaporated this will burn of before the
metal evaporated onto the glass. The layer on the glass however is mainly barium in the end.
The coating on the cathode is a mainly barium oxide, strontium and calcium oxide might be added, too. Usually it is applied in the form of barium ( or other ) carbonate as the
oxide would not be practical to handle in production. When the cathode is first heated in production, the carbonate will convert into the oxide and the gassy byproducts are
removed by a vacuum pump or the getter.
In operation some of the oxide is reduced to metallic barium which effectively is the electron emitter, not the oxide iteslf. This is btw one reason a tube with this kind of cathode needs a getter,
no matter how clean you materials and process are ( which today they are usually not ;-) The cathode itself produces some oxygen in operation which has to be removed.
The gold plating on the grid also helps in reducing unwanted electron emission from the grid, but there might be other reasons I am not aware of.
Nice Idea! Thanks for answering my Question.
You guys are AWESOME
Great! When i was 10 years, last 42 years i colect tubes and always Impres from all this inside. Wstching hours, want to understand all this.... thsnks a lot,
Moti from Israel
The difference in sound seems to be audible even within the linear range of tubes, if they truly have a linear range.
Swapping tubes to change the tone is called "tube rolling" and is popular with some tube amp lovers in their home stereos. Some tube fans keep sets handy, so their amp can sound one way for a while, and then a bit different when they feel like a change. It's almost like changing the flavour of your food.
I use Class D amps myself, so I spend more time listening than tweaking.
Very cool demonstration...;)
TANX for sharing..!
5 Stars from the Blue Tube Project!!
great video :)
If that is what you believe, and you are happy with that, so be it.
Awesome Tube Disection Video :-) Now tell me a secret how to get rid out of rattle on Bugera V5 EL84 or rather 7189A, as that drives me crazy ;-)
Nice video! Thank you!
Very informative and fun to watch video! A beam tetrode 6V6 was chosen instead of a pentode 6V6. Cool to see what a beam former looks like!
I know that my comments are not popular on this subject, but it depends upon whether one is aiming at sound REPRODUCTION - in which case one wants maximum transparency, no colouration, flat response, maximum loudspeaker damping and a linear transfer characteristic. That can ONLY be produced by a well designed solid-state amp. If, however, you're using an amp for sound PRODUCTION, you want tube distortion to suit part of the sound coloration of an electric guitar.
Unbelievable. Amazing tech. I just love it. A beautiful science.
Good stuff!
If you're talking about CREATING a musical sound - then yes, the distortion in the amplifier (ie an electric guitar amplifier) becomes a part of that sound creation. However, distortion of any kind plays no useful part in sound REPRODUCTION, so that in the playing of records, the distortion introduced by a valve amplifier is difficult to justify.
thanks! this will help me with my project
Great video thanks
glad you liked it.
As a trained electrical engineer, 55 years old, I have to say that the fascination with tubes escapes me. The need for an output transformer between the output tubes and the speaker wrecks phase response and loudspeaker damping, especially at low frequencies. Tube distortion figures, even with moderate feedback, are bad. It may be an acceptable type of distortion, but it's distortion nonetheless. I would reccomend reading books by the the solid-state designers Douglas Self or Linsley Hood.
To a guitar player the distortion produced by a tube amp is not only acceptable, it's desirable. It may be called an amplifier, but it is really an amplifier/effects unit. I agree that if you're looking for hi-fi and you don't have money to burn, then solid state is the only way to go.
As a mature 65 year old EE, I suggest you listen to a Vintage MC 75 system
playing vinyl. And then reconsider. Yes there are a bunch of myths about tube sound. And there are nonsense terms dangled around the audiophile community, yes they think power cords and crystals improve the sound. Nut case exist.
But these system do sound fantastic. Also note the Mcintosch transformers are
amazing devices. Chill Mr. Trained, and listen to the music.
Playing Steely Dan there... nice!
tube amp are the best !
Amazing channel , Subscribed
Tube Depot rules. Fast shipping and great quality on matching/testing. Just changes out tubes and it made a hug difference in my amp. Also on sale.
I know what you are talking about, however, that subtle tube distortion adds TONE...thickening the overall sonic presentation in a noticeable way...judiciously applied low level harmonic distortion adds characteristics that can be manipulated by the variable attack of the musician...aspects which seem unavailable which many solid state amps...so it really is an interesting discussion and depends on what one is after in expression.
There is a reason why the most prestigious and expensive home theater equipment is tube-amplified...
What an excellent video and lesson!!! Any chance to have a similar video on the 300B? I have a Felix Audio Envy headphone amp and would love to learn how the 300B works. Thanks very much!
Perhaps you should listen to a Fender Twin Reverb guitar tube-amplifier. It just doesn't get any cleaner than that. The tone just "sparkles", and distortion is very low until the amplifier is driven into saturation...
I ran those JJ 6v6s right about 420-430v on plates 400-410 on screens for a good 6 months sounded totally kickass I loved the midrange of them when wound up it was almost EL34 like in a way or maybe still kinda 5881 or 7591 like hard to explain but still it was a more interesting midrange character as well as nice bass the highs were a bit on the harsher side for my taste though. but after about 6 months they started sounding lifeless pretty much.
I found the misplaced test lead wire, & my parts are here from China so my new curve tracer test jig is nearing completion! I made it like a 570 test jig, only with P1, P2, G1, G2, and K1, K2 coming from the tracer, and G1, G2 and htrs coming from separate supplies. You patch in to a row of 2x12 5 way jacks accordingly. R174 cabled with BNC cons go to a switch that selects tube 1 or 2. The heaters just stay on in both tubes. I have every common socket except subminis. Forgot them, Hmm>??
That tube looks exactly like the ones I dissected in the seventies.
Are modern audio amp tubes still exactly the same?
@TubeDepotTV Thank you
I am wondering what your opinion is on a hybrid amplifier? A tube used for the preamp stage, and transistors for the driver and output stages. If made correctly, could you eliminate the need for an output transformer? You would probably need one between the preamp and output stage:( ?
You should still get that tube sound though, a friend of mine eliminated the need for an output transformer by wiring a bunch of cathodes of preamp tubes together. That seems like a waste of tubes though!
@Timmy Mcfistfull, the beam forming plates and staggered grids were added to power tubes in the 1930s as a solution to the Pentode patent owned by Philips/Mullard. The Pentode has an extra suppressor grid with no beam plates. Anyways, read the wiki on pentodes and tetrodes before making more rediculous comments..
so the stronger the positive signal the more electrons to the plate if im understanding correct? so the harder you play?
@TubeDepotTV Thank you, it makes it a little easier to comprehend. I am still a little vague as to how exactly the Triode actually " Amplifies " the input signal, Is it getting a kick from the extra Grid Voltage?
hermoso hace años que queria saber que habia dentro. gracias tube depot tv
Oh boy.... Lotsa notes...
In England a tube is the subway, a valve is a tube
Part of the problem was the underrated screen resistors those Legacies had lol
I hope no one attempts to pull a hot tube out of a live amp after seeing that intro. It was a cold one set behind the amp people. Power tubes get hottt don’t scald yo self.
I don't think the word emit is harder to understand then the word boil. Further, I'm a physicist and I find it equally hard to understand the mechanisms behind the physical terms emit and boil. A well. just a thought. Nice channel you got going!
combined with shipping from former soviet countries, i now know why they are so damn expensive!!
"Expecially!"
Cool Video! How did you cut the Tube's Glass? Can you cut them with a normal Glasscutter?
@TubeDepotTV
school project actually, on vacuum tubes
I would buy these before getting JJs ever again though I'll tell you that xD
Теперь знаю что внутри)))
I'm enjoying my old Tungsol 6550s mostly right now :) stunning highs and lows waaay too laid back of a midrange though. KT88s are far more musical in the mids in my opinion xD. I thought about getting these SEDs though or Svetlanas to try out not sure doesn't sound that bad though, I had some JJ 6l6 and 6v6 they both died within 2 years and after a year they sounded lifeless lol. and the JJs have the most horrible matching I ever seen lol talk about drifting to hell and back lol.
Lol, any part of the circuit that shapes the sound has a sound. Valves are no exception; they aren't just a simple amplifier, they're very complex and hard to describe. They're as much a part of the circuitry as the biasing resistors, high-pass and low-pass filters around them. When we say they have a sound it's in that context, how it shapes sound there, just like you'd describe a strat's tone in the context of being connected to an (clean or dirty) amp. Not my fault you can't hear it ;).
lol I had no idea tubes were so complex! :p
awesome video, love your channel. I have a novice question I hope you can answer, I have a Fender Deville and have heard everything from "you need to let the tubes heat up for at least 5 minutes" to "just 30 seconds" to "it doesn't matter if you heat them up at all just flip on and off standby and you're good to go" in short what's the correct warm up time?
Odd though I was running some 6l6 before I put in the El34s never had a single problem with them.
Wow this was an awesome view. Thanks so much for the info. Would you say this is what makes the winged c tubes worth the extra money? Thank you, subscribed.
Might be true, but there are iron alloys much cheaper then gold that can be used if duration is the main focus.
What's the white cathode coating made from? Does it have a lower work function than the metal and is that why a coating is used?
Questions, questions questions....
how did you cut the glass?
Don't recall the model. Bought it from a guy who lost his ass in a poker game. Played the crap out of it for years. I bought a Line 6 spyder 3 awhile back. It's really not too bad but, it's just not scary good like a tuber. Got some software to clean up the old LPs that I'm putting on CD. Then I'll check for subliminal back masking before I stash em away. All this time the old turntable reclaims it's share of daylight.
@TubeDepotTV yeah it wuz a grate video!
Does the Tube Depot manufacture its own tubes?
I am just wondering because of your logo on the bases. Are there other tube manufacturers still in the U.S. ?
What are the plates and wire's made of for precious metals recovery
Yeah too good - Wish I could shred like that but fingers dont do what they aughta these days lol. sorry if i confused you
Мужик, да ты крутой!) Очень хороший канал! Привет из России!
Thanks for the great comment.
I know this is very old video but if your still around maybe you can answer me a question. That tube you pulled apart looked pretty darn solid and not sure how normal use could cause shorts or make a tube fail. What exactly happens when a tube gets older and starts to not perform as good as it did when new? Does that coating stop producing electrons as well ?
A tube wouldn't typically go shorted in normal operation unless there was a preexisting manufacturing defect. But rough handling or electrical overloading can cause damage.The cathodes do become less emissive over time, however, which is the normal wear-out failure mode of a tube.
@@Agent24Electronics Thanks for the response . So when older people say they used to used tubes in there amps for 20 years without changing them this is actually possible?
@@Jennifer_Prentice Cathodes are supposed to last 1000 hours, but many will do much more than this.
actually your anode is what they call a a suppressor grid and your outter plate is actully your collector another words your cathode emits electrons to your the collector and your collector is the outer plate of a tube your anodes are your control grid suppressor grid and your screen grid and that inner plate is actually your suppressor grid thats how a beam power tube such as a 6L6 or 6JS6 or what ever like tube works.
What are these secret coatings on the screens and cathode?
Your missing my point. Valves do not have a sound. It's only the circuitry they operate within that imparts a 'sound' perceived by the listener. So if the HF response is rolled off early for example, this may be perceived as a warm tone, but it is not the valve causing that. Two valves of the same type may sound differently, only due to manufacturing tolerances that require different circuit adjustments. There is no mystery to electronics.