This video closed the gap for me. To transition from wanting to build tube amps to building tube amps. My first amp almost blew up from a simple crossed wire. I then learned how to check my work as it progresses. The amplifiers that followed were so full of the tone I was searching for. Thank you Roger your videos were there at the right time for me. your a great teacher keep it up.
Thank you! this is very useful My grandfather gave me a tube amplifier a year ago. It was EL84 single ended around 5 watts. And since they fasinate me Specially after restoring the amplifier my grandfather gave me. Im hooked
This has to be the most sensible informTive valve amp video I've seen. Really good, Thankyou for explaining things I have never quite grasped. You simplified things in minutes.
That center post on the socket is usually grounded in radio work as it acts as a bit of a shield to the other pins. Of course a well bypassed B+ supply could do essentially the same thing there.
Having worked in valve audio and having seen the alarming level of misinformation on the net, this video is a welcome break from that! :o) I had a number of old friends, most of whom have sadly passed away, who I gleaned information from and its just something of a dying art. Most of them where trained by the military ('National Service' in the UK) and made very neat circuits. I'd get my ears boxed if I did things anywhere like I see on the net! I agree; Valves are wonderful to work with. I still haven't got my head around these new fangled transistors.
Yes there is an alarming level of misinformation on the internet. I plan to keep these coming and I will be opening a school in the San Francisco Bay Area soon. I will be posting some of those lectures. We are looking for anyone who wants to help with video editing and posting. Please contact me at ramtubes@gmail.com
Music Reference Hoping there will at least one EE-grade listener, who tells you when you´re talking some "off-limits" stuff, as here in this video there is no proove of nothing, you just say something and that´s it...Proove at least your bias point...! Is this what you call "teaching" ?
Diggi Thal This guy is awesome and he isn't doing anything off the chart. look at just about any guitar or radio preamp and you will see the same things and values of components as he used. His whole goal is to show how easy tubes can be to work with and encourage others to work with them, NOT give an EE lecture. This is for the DIY people. If you want EE lecture, go get some books. If you are too lazy to read and work a calculator, do something else and stop criticizing others because they didn't do something the way you wanted them to. If you demand something else, make your own video.
Very clear video. I remembered my infancy constructing UCL-82 one tube amp. Do you have a scheme of this - UCL82. You do not need a transformer if you pu two in series. I want to do for iPod. Tank you and Congratulations for the class
You kind of danced over the purpose of the 470uF cap on the cathode resistor. My assumption is that it helps keep the selfbiasing 2V no matter how the cathode current varies. I found this to be an EXCELLENT tutorial. I've now doubled my understanding of tube based amplifiers.
+David Dennis Actually the cathode bypass capacitor relieves a symptom called cathode degradation which if left unchecked will kill the gain of the tube by a significant amount. The value of the capacitor is high so that low frequency electron congestion can bypass the bias resistor and bass tones are not suppressed, whereas if you put a lower value (for instance 1 uF) you would only relieve the high frequency congestion and only restore the gain of treble tones, while leaving bass and mid tones suppressed.
Great video. Rogers personality, and calm demeanor really help me personally to understand some of the dynamics ive found difficult in the past. Any chance of a follow up to this?
For you, what is the best valve that exists for pre amplification? which one would you choose according to your experience? always talking about circuits for audio reproduction ...! thanks for your answer!
I forgot to ask Roger, do you have a website I can refer to? It would be really cool to see some more designs you might have. Please let me know if you I do, oof not than thanks anyways. Regards, Steve
Thanks so much! That's a really nice, clearly described, and to-the-point guide. Much appreciated. I sort of stumbled upon this by accident, whilst looking up some other things - but I have often wanted to get such a practical and concise description of these aspects of valve audio circuitry. SUPER! keep it up (:
At 5:42 you mention who you get the tube's from, but the background noise cancelled out where you get them from! BTW- Great Job! I have built one of these using only 12V on the plate. Yes I know, Harmonics, but it worked. For those that don't know, you don't mention the value of the Cathode Resistor.
Ted Mieske tubeaudiostore.com is where the RAM tubes can be purchased. RAM is Roger’s tube company. He created software to match the tubes. Good luck......!
A great tutorial thank you. I have 2 questions. What would be a typical value for the cathode 1/4 watt resistor? If 200V is at the power supply, where is the other 98 Volts sitting? Thank you for your time.
The cathode resistor is typically 1.5kΩ. The power supply voltage is shared between the plate resistor, the tube and the cathode resistor. E.g. there could be 2 volts across the cathode resistor, 98 volts across the tube and 100 volts across the plate resistor.
Hello, Would this kind of setup provide some overdrive or distortion as well? I am looking for tube preamp, that would just provide the boost and the amplification and not mess the signal itself. Regards
I like that 9 pin socket. Not sure though why you would need a 470uf cathode bypass..that's overkill..typically all you need is about a 22uf for good bass response.
I hate to ask this, but why do I like the sound of the expensive fender amps, but not the cheaper pawn shop tube amps? Will this simple circuit sound good, or do you need to work on the equalization or whatever that makes the fender type sound?
I have a vaporizer amp. It sounds as good as many more expensive amps if you swap out the speakers, which are properly rubish seakers, for G10 greenbacks.
what classes do you take in school to learn how guitar amps work, and the general electricity for things like speakers, cables, and radio stuff. I don't want to graduate taking a bunch of classes. just enough to know how to plan and build my own things.
I have a question, can one build a preamp but use it as a low wattage class a power amp in order to get high tube gain tones without pissing off the neighbors in adjoining apartments?
Hallo. could you suggest a high definition balanced triode config. with such military tubes as used by Audio Research. l d like to have it built.my ultimate pre amp.
If this is to be a preamp for audio , what would determine the maximum voltage out regardless of how high the supply voltage chosen? Any one please answer.
hi dear, how are you? please, maybe you can help me in my doubt, i want to built in my own home my LA2A original audio circuit, using commum electronics components of the current stores. how dificult is it for a person that have basic eletronic knowlogdes? will the quality near as the old original if i use exactly the same original eletronic plan? does it will be worth in cost of money, time spent, and quality? i saw the plan, i think it will be easy, maybe i can make it to sell if it works well, could you clear me better? maybe can i start with a more simple project to learn?
For safety reasons I don't run anything to the centerpost except grounds. Running the B+ to it makes high voltage DC theoretically accessible from above, all it takes is one touch and you may have a corpse on your hands. There are times when my B+ rail is kicking out 400v DC, that is a lot to have shooting down through your toes. Otherwise, GREAT video, really well explained.
I saw a Japanese amplifier where they had put LEDs shining up through the centre, it looked pretty good actually! Totally agree on the HT. Its good practice as anyone who's worked with 211s or 845s will tell you: 250v HT - Ouch! 400v HT - Sit down with a cup of tea and get your nerves back together. 1,300v HT - Goodnight Vienna.
Also what if you run the 2 triads in series for say a distortion channel? Does it work like that? I'm trying to understand the components of a guitar amp.
Not really without looking at the actual transformer. I'm just learning this stuff myself. Lol. I know a little about electronics I'm trying to understand the relationship between various parts and their affect on tone.
Allen Toler .......um........i was listernin to the man in his studeo talkin amps.........he said.......if you use the highest qualerty components ...you have the best sound........eg....use high grade coper wire ,the purest steal,inserlate everything........mabe........use aluminuim foil and wrap it around the transformers..!!?
Hello! I have an electroguitar tube amp but i need headphone/record out for it. As far as i know there is one preamp tube and 2 power tubes in the amp. What i need to do in order to connect it to pc sound card's line-in? (i made a cable with one side golden instrumental jack and other end with multimedia jack, so except this one)
Thats a massive question - without a model number and no schematic I'd guess that there is a pair of output valves, a diode phase splitter, a driver and before that is where you would put an output BUT! you need to measure the signal voltage to know where you stand. Also, this would be a preamp output and will not sound anything like the amplifier does post output stage and speaker. I would much rather recommend getting a microphone and a decent recording interface as you'll have a way better time.
My very thanks to you pal. I'll check and stand at the lower voltage outputs i guess.. I'm not sure maybe i'll buy just a preamp tube pedal or something IF! i find.. At least i know where to start now.
I am quite the noob, hence why I am viewing this video my self. But, yeah, you would use a power transformer. Like this: (I dont really post on youtube so I am not sure whether or not the link will work.) www.mouser.com/ProductDetail/Hammond-Manufacturing/272JX/?qs=3TG34Bgp1HChVFd5VPojqw== That particular transformer is quite a bit of overkill for just a pre-amp AFAIK. I referenced this transformer from a 50w power amp schematic that you can find at ax84.com
No problem man! I am learning so much lately and excited to share. I figure, the more I share what I THINK I know, the more opportunity I have to be corrected. Cheers.
wow... very interesting. Suggest you number your videos to make it very easy for us to follow the chain of knowledge you are sharing. Realy helps when binge watching!...
I'd like our commercial studio to start selling our own line of products. These resources are wonderful, but I'm wondering if there are people like this guy here that would be willing to build for us...that would be amazing lol
+Nicholas Smerk True enough, if you want a really quiet front end. I think he was simplifying the locations you _could_ use for ground. As a rule, I always tie one of these four ground lugs to a tightly fitted single chassis ground lug. I don't depend on the tube socket being grounded solidly to the chassis by its hardware.
The socket ground makes a nice ground and its close. The problem with star grounding is that it can result in long wires going to the one point. In grounding shortness is key.
I would advise using a transformer but if you insulate the whole amp and you could also use a polarized plug and use a few capacitors like they used on the ac dc 5 tube radios you could get by without a transformer but you better know tube electronics before taking shortcuts in tube circuits.
hi joey here, ? will it work if you put 12 volts to 16 volts on a 12ax7 tubes, because china made a 12 volts tubes, I understand how tube amplifier works, but what's dangerous is 200 to 400 volts.
Great video but I was taught electronics first in Jr. High in the mid 1960's and then in the Navy in the early 1970's. Electron flow is everything. I know they teach the "Current Flow" method but that is really a misnomer. The current actually flows the same direction as the electrons. The spaces, or holes, the electrons use to occupy flow in the opposite direction. If there are no free electrons to replace the ones that left a positive potential is developed but no current is detected. Current is defined by the number of electrons moving past a point in a defined unit of time. This has always been a bit of a sticking point with me and I really cannot understand why Engineers and others continue to use the Current flow , Positive to Negative, when actually it is not what is happening.
+megaohmz Actually that isn't really true, certainly in a free electron metal. The conduction elextrons move in the conduction band and don't leave 'holes'. The solution for the electron on a periodic potential yields Bloch wavefunctions, and when the electrons are almost completely free (as in a metal) you get a continuous conduction band. Current flows with the electrons, as that is what current is. The concept of holes makes more sense with semiconductors when the electrons are not free, and the quantum mechanics gives band gaps. Like Richb313 I find the current flow method confusing too.
Went through CTM "A" school in the late '90's and we were taught Electron flow is negative to positive, we were also taught "Hole Theory," as it pertained to semiconductors. It was what was deemed the "I believe" section of training. We were also taught "Current Flow," as it made tracing "signal flow" through the circuit easier...but it was stressed that "current flow" was not how the electrons actually moved. I think most people use the "current flow" method to explain circuits, as it makes it easier to relate "signal flow," but few stress the actual electron flow is negative to positive.
Before the discovery of the electron, the early pioneers of electrical and electronic theory did not know what current actually was, or which way it was flowing. There was a meeting and it was arbitrarily decided that it flows from positive to negative. By the time it was discovered that it is in fact electrons flowing from negative to positive, so much electrical and electronic engineering had been based on 'conventional' current that it was impractical to change. From personal experience, it is not difficult to think in terms of whichever system is more appropriate for the subject. E.g. electron flow to understand a vacuum tube, and conventional current to understand a preamp stage.
It's really a bummer that there is no follow up to this video. This is exactly the sort of step by step I've been looking for as a newbie, and unfortunately it's only partial.
Vintage-Audio-Workshop If you are still working on it, Just a suggestion but a rather realistic one..... It would be nice to see something like this but also to get out a real schematic such as a Fender, Vox, Marshall, etc. and go through the circuits, identifying them and pointing out the differences in components used and why. I have been studying as best I can and can almost identify the different parts but how different values affect tone, is still eluding me. In essence a complete tutorial on how tube amps work would be very helpful to us solid state guys. :-D A monumental task, to be sure but WOW, what a help for us beginners.
I have a couple of questions. Why are you running the tube at such a high plate voltage if this is a 12 series tube? Aren't they happy with a 12 volt power supply? Also, how would I get a better bass response out of the distortion channel of my solid state Randall Warhead? Thanks.
the "12" in the its "name" e.g. 12AX7 is for the filament, the heater, not the plate voltage. To operating a tube you need three voltage souces. One for the filament, the heater, as tube needs some heat to produce free "flying" electrons. The do have to come out somewhere, and that´s the heater. Next is the plate voltage, no plate voltage no amplification. As the electrons comes out of the filament (=kathode) they need to know how to go....that´s the plate, so to let the electrons know their way, apply a high voltage at the anode and the electrons will go there.... And this leads us to the third voltage, the grid bias voltage. When applying a high voltage at the anode, all electrons where called to fly to the anode....but the anode is not able to take them all together at the same time. Doing so will simply melt down the metal plate which forms th anode. So the flew of the electrons need to be controlled. This is what the grid does. Making the grid negative the electron stream is bekomming lower...here is the control function... Hope that helps...;)
A sensible tutorial on valves (tubes) for a change, with a logical approach that won't result in my being burnt to death, electrocuted to death, or getting AIDS.
This video closed the gap for me. To transition from wanting to build tube amps to building tube amps. My first amp almost blew up from a simple crossed wire. I then learned how to check my work as it progresses. The amplifiers that followed were so full of the tone I was searching for. Thank you Roger your videos were there at the right time for me. your a great teacher keep it up.
Thank you for pointing out that electron flow and conventional current are in opposite directions. Kudos😊
Thank you! this is very useful
My grandfather gave me a tube amplifier a year ago.
It was EL84 single ended around 5 watts. And since they fasinate me
Specially after restoring the amplifier my grandfather gave me. Im hooked
Very helpful! It's great to read diagrams and see other people's completed projects but hearing someone talking about how to do it is fantastic.
This has to be the most sensible informTive valve amp video I've seen. Really good, Thankyou for explaining things I have never quite grasped. You simplified things in minutes.
Wow, it all make sense. Finally a good tutorial on tubes.
thanks for your support and for watching
Great video! One thing I'm a little unclear on is the DC voltage present on the grid. Is it close to ground??
That center post on the socket is usually grounded in radio work as it acts as a bit of a shield to the other pins. Of course a well bypassed B+ supply could do essentially the same thing there.
Dying art of knowledge. Thanks so much for lying it out this project as you have here while explaining the contents value and purpose.
Best video I've seen on amp design... actually, one of the only videos i've seen on the topic. Please keep them coming!
Damn I love TH-cam, I wish it was around when I was a kid tho. Great video, thank you!
Having worked in valve audio and having seen the alarming level of misinformation on the net, this video is a welcome break from that! :o)
I had a number of old friends, most of whom have sadly passed away, who I gleaned information from and its just something of a dying art. Most of them where trained by the military ('National Service' in the UK) and made very neat circuits. I'd get my ears boxed if I did things anywhere like I see on the net!
I agree; Valves are wonderful to work with. I still haven't got my head around these new fangled transistors.
Yes there is an alarming level of misinformation on the internet. I plan to keep these coming and I will be opening a school in the San Francisco Bay Area soon. I will be posting some of those lectures. We are looking for anyone who wants to help with video editing and posting. Please contact me at ramtubes@gmail.com
Music Reference
Hoping there will at least one EE-grade listener, who tells you when you´re talking some "off-limits" stuff, as here in this video there is no proove of nothing, you just say something and that´s it...Proove at least your bias point...!
Is this what you call "teaching" ?
Diggi Thal
Its free, what do you want? If you really want to know then open a book and your mind.
Diggi Thal This guy is awesome and he isn't doing anything off the chart. look at just about any guitar or radio preamp and you will see the same things and values of components as he used. His whole goal is to show how easy tubes can be to work with and encourage others to work with them, NOT give an EE lecture. This is for the DIY people. If you want EE lecture, go get some books. If you are too lazy to read and work a calculator, do something else and stop criticizing others because they didn't do something the way you wanted them to. If you demand something else, make your own video.
Very clear video. I remembered my infancy constructing UCL-82 one tube amp.
Do you have a scheme of this - UCL82. You do not need a transformer if you pu two in series. I want to do for iPod.
Tank you and Congratulations for the class
An extremely informative and inspiring video making the concept feel more approachable. Thank you
You kind of danced over the purpose of the 470uF cap on the cathode resistor. My assumption is that it helps keep the selfbiasing 2V no matter how the cathode current varies. I found this to be an EXCELLENT tutorial. I've now doubled my understanding of tube based amplifiers.
+David Dennis Actually the cathode bypass capacitor relieves a symptom called cathode degradation which if left unchecked will kill the gain of the tube by a significant amount. The value of the capacitor is high so that low frequency electron congestion can bypass the bias resistor and bass tones are not suppressed, whereas if you put a lower value (for instance 1 uF) you would only relieve the high frequency congestion and only restore the gain of treble tones, while leaving bass and mid tones suppressed.
it’s ok to use 16v ??
Great video. Rogers personality, and calm demeanor really help me personally to understand some of the dynamics ive found difficult in the past. Any chance of a follow up to this?
do you have the other half of the video ? very clear explanation thanks
good job on going at it step-by-step and making it easy to understand
For you, what is the best valve that exists for pre amplification? which one would you choose according to your experience? always talking about circuits for audio reproduction ...! thanks for your answer!
Great explanation. Thank you Roger for sharing your knowledge. Kind regards from Mexico!
I forgot to ask Roger, do you have a website I can refer to? It would be really cool to see some more designs you might have. Please let me know if you I do, oof not than thanks anyways. Regards, Steve
Thanks so much!
That's a really nice, clearly described, and to-the-point guide.
Much appreciated.
I sort of stumbled upon this by accident, whilst looking up some other things - but I have often wanted to get such a practical and concise description of these aspects of valve audio circuitry. SUPER!
keep it up
(:
At 5:42 you mention who you get the tube's from, but the background noise cancelled out where you get them from! BTW- Great Job! I have built one of these using only 12V on the plate. Yes I know, Harmonics, but it worked. For those that don't know, you don't mention the value of the Cathode Resistor.
Ted Mieske tubeaudiostore.com is where the RAM tubes can be purchased. RAM is Roger’s tube company. He created software to match the tubes. Good luck......!
@@PoppyHoc- Thanks!
Great informational video! Helped to disband some incorrect thoughts I had about using Tubes in single-stage amplification. Super helpful :D
A great tutorial thank you. I have 2 questions. What would be a typical value for the cathode 1/4 watt resistor? If 200V is at the power supply, where is the other 98 Volts sitting? Thank you for your time.
The cathode resistor is typically 1.5kΩ. The power supply voltage is shared between the plate resistor, the tube and the cathode resistor. E.g. there could be 2 volts across the cathode resistor, 98 volts across the tube and 100 volts across the plate resistor.
98 Volts in on the plate. Cathode resistor typically a few thousand ohms. Try different values that give you 90-120 in the plate.
Hi Roger, I may have missed it but I don't think you gave any indication of what value the cathode resistor might be?
.Hi Roger...u said u would later tell us where the power serply comes from for your eg. of this tube pre amp.
Thank you, you have a good sence of explaining circuts. This will help in my frankinsteining
.
Hello,
Would this kind of setup provide some overdrive or distortion as well? I am looking for tube preamp, that would just provide the boost and the amplification and not mess the signal itself.
Regards
I like that 9 pin socket. Not sure though why you would need a 470uf cathode bypass..that's overkill..typically all you need is about a 22uf for good bass response.
MUSIC REFERENCE,
Is the power tube AC load line mean the max output wattage? or what is "the load" of the AC load line and DC load line?
He needs a .047 cap on a 500k pot rolled down 🤣🤣🤣
This is the Best introduktion too tube amps, I ever have seen. thanks! If I Want to use it as a riaa for MM, what to change ?
I hate to ask this, but why do I like the sound of the expensive fender amps, but not the cheaper pawn shop tube amps? Will this simple circuit sound good, or do you need to work on the equalization or whatever that makes the fender type sound?
I have a vaporizer amp. It sounds as good as many more expensive amps if you swap out the speakers, which are properly rubish seakers, for G10 greenbacks.
moreanimalspirits it all depends where they cut the corners to get the price down.
Nice presentation.
what classes do you take in school to learn how guitar amps work, and the general electricity for things like speakers, cables, and radio stuff. I don't want to graduate taking a bunch of classes. just enough to know how to plan and build my own things.
physics, aircraft and small engines(If the teacher teaches electric theory)
HOWEVER, you won't learn about amps or sound stuff in specific.
Thanks for explain this article, really we need more people like you, thank you !!.
I have a question, can one build a preamp but use it as a low wattage class a power amp in order to get high tube gain tones without pissing off the neighbors in adjoining apartments?
check out the matsumi valvecaster if you havent already
For you the 6bx7 tube is good for make the line preamplifier?
Very informative video, thanks for sharing your idea of making our custom tube amplifier and it is quite impressive to though.
This was amazing!
Hallo. could you suggest a high definition balanced triode config. with such military tubes as used by Audio Research. l d like to have it built.my ultimate pre amp.
I have a pre amp running 12ax7 at 48v 😮
So I can get more head room by increasing the V?
When people use 2 12ax7s in parallel they are most likely making a current driver to drive somthing like a reverb circuit in a guitar amplifier.
what's the resistance for the cathode resistor?
Could you point me to a web page for the tubes you represent?
Thank you
If this is to be a preamp for audio , what would determine the maximum voltage out regardless of how high the supply voltage chosen? Any one please answer.
Don't you need a grid stopper resistor? typically 100-470k
hi dear, how are you? please, maybe you can help me in my doubt, i want to built in my own home my LA2A original audio circuit, using commum electronics components of the current stores. how dificult is it for a person that have basic eletronic knowlogdes? will the quality near as the old original if i use exactly the same original eletronic plan? does it will be worth in cost of money, time spent, and quality? i saw the plan, i think it will be easy, maybe i can make it to sell if it works well, could you clear me better? maybe can i start with a more simple project to learn?
An LA2A has some special parts you wont find at a common electronics store. The Light cell is very important.
For safety reasons I don't run anything to the centerpost except grounds. Running the B+ to it makes high voltage DC theoretically accessible from above, all it takes is one touch and you may have a corpse on your hands. There are times when my B+ rail is kicking out 400v DC, that is a lot to have shooting down through your toes. Otherwise, GREAT video, really well explained.
I saw a Japanese amplifier where they had put LEDs shining up through the centre, it looked pretty good actually!
Totally agree on the HT. Its good practice as anyone who's worked with 211s or 845s will tell you:
250v HT - Ouch!
400v HT - Sit down with a cup of tea and get your nerves back together.
1,300v HT - Goodnight Vienna.
B plus does not kick out, also unless you stand on a grounded metal plate, touching 400 volts will not harm you. Go get you facts straight.
Also what if you run the 2 triads in series for say a distortion channel? Does it work like that? I'm trying to understand the components of a guitar amp.
....Alan,do u know how to attatch the transformer at b+?
Not really without looking at the actual transformer. I'm just learning this stuff myself. Lol. I know a little about electronics I'm trying to understand the relationship between various parts and their affect on tone.
Allen Toler .......um........i was listernin to the man in his studeo talkin amps.........he said.......if you use the highest qualerty components ...you have the best sound........eg....use high grade coper wire ,the purest steal,inserlate everything........mabe........use aluminuim foil and wrap it around the transformers..!!?
Watch "Uncle Dougs" Videos....;) This video here is not very informative it rather tells you nothing....
Whats the feasibility of making a tube microphone preamp?
What a great video !
Is it possible to use the 12ax7 with 12v dc current? I would like to make a tube booster pedal, adding a footswitch(obviously).
No.
nice video, willbe nice if you should do a video about srpp topology ,
Can you tell me where you got the tube sockets from? Please
Try www.parts-express.com
Hello! I have an electroguitar tube amp but i need headphone/record out for it. As far as i know there is one preamp tube and 2 power tubes in the amp. What i need to do in order to connect it to pc sound card's line-in? (i made a cable with one side golden instrumental jack and other end with multimedia jack, so except this one)
Thats a massive question - without a model number and no schematic I'd guess that there is a pair of output valves, a diode phase splitter, a driver and before that is where you would put an output BUT! you need to measure the signal voltage to know where you stand. Also, this would be a preamp output and will not sound anything like the amplifier does post output stage and speaker.
I would much rather recommend getting a microphone and a decent recording interface as you'll have a way better time.
My very thanks to you pal. I'll check and stand at the lower voltage outputs i guess.. I'm not sure maybe i'll buy just a preamp tube pedal or something IF! i find.. At least i know where to start now.
Would you use an input transformer to get a high enough voltage for your B+?
I am quite the noob, hence why I am viewing this video my self. But, yeah, you would use a power transformer. Like this: (I dont really post on youtube so I am not sure whether or not the link will work.)
www.mouser.com/ProductDetail/Hammond-Manufacturing/272JX/?qs=3TG34Bgp1HChVFd5VPojqw==
That particular transformer is quite a bit of overkill for just a pre-amp AFAIK. I referenced this transformer from a 50w power amp schematic that you can find at ax84.com
Thank you!
No problem man! I am learning so much lately and excited to share. I figure, the more I share what I THINK I know, the more opportunity I have to be corrected. Cheers.
Fantastic! Thank you so much! Jon
wow... very interesting. Suggest you number your videos to make it very easy for us to follow the chain of knowledge you are sharing. Realy helps when binge watching!...
+Paul Gdry Derp. you need to post more videos! You are too good at this not to, time considerations aside..
very well explained learned heaps
Awesome video!!!
So i can do a simple drive control by just putting a variable resistor on the cathode?
I meant plate
I'd like our commercial studio to start selling our own line of products. These resources are wonderful, but I'm wondering if there are people like this guy here that would be willing to build for us...that would be amazing lol
can I use the 12AX7 two anodes to have a stereo output, like right channel in one 6v and left channel on the other 6v?
yes
I find it odd that you would consider grounding to the socket mount. I thought it was best to star ground everything to one point?
+Nicholas Smerk True enough, if you want a really quiet front end. I think he was simplifying the locations you _could_ use for ground. As a rule, I always tie one of these four ground lugs to a tightly fitted single chassis ground lug. I don't depend on the tube socket being grounded solidly to the chassis by its hardware.
The socket ground makes a nice ground and its close. The problem with star grounding is that it can result in long wires going to the one point. In grounding shortness is key.
I tried to make a 4 stage pre-amp, for more distortion... it sounds pretty bad...
Hi my compliments from italy
Could i use a 5u4gb for the rectifier tube?
Do i need a transformer for B+ if in my home in plugs i have 220 V powersource ?
yes you need it to be isolated from the power line for safety
thanks :)
I would advise using a transformer but if you insulate the whole amp and you could also use a polarized plug and use a few capacitors like they used on the ac dc 5 tube radios you could get by without a transformer but you better know tube electronics before taking shortcuts in tube circuits.
also they used output transformers on the output to match it with the speaker. so you were safe from line voltages on the output jack or headphones.
you always need a power transformer for isolation from the line and to get the high and low voltages.
What is your take on the low-voltage (9-12 volt) 12au7 based drive pedals?
Unless they step it up with a voltage multiplier its too low for a good plate voltage. The tube can draw no reasonable current at that low voltage.
would it work for turntable pre amp?
what is the value of cathode resistor?
Typically 1.5kΩ.
Very well done !
Hi, if a 12AX7 glows at the top and the bottom is that a problem please?
No
Bob Lucas Thank you
Thats normal
i just feel you how you make it easy i just learn from you
hi joey here, ? will it work if you put 12 volts to 16 volts on a 12ax7 tubes, because china made a 12 volts tubes, I understand how tube amplifier works, but what's dangerous is 200 to 400 volts.
400 volts DC is not going to kill anyone. AC kills not DC.
Huh, what are you saying?
Awesome video! Very informative, thank you :)
That sounds fine.
Great video but I was taught electronics first in Jr. High in the mid 1960's and then in the Navy in the early 1970's. Electron flow is everything. I know they teach the "Current Flow" method but that is really a misnomer. The current actually flows the same direction as the electrons. The spaces, or holes, the electrons use to occupy flow in the opposite direction. If there are no free electrons to replace the ones that left a positive potential is developed but no current is detected. Current is defined by the number of electrons moving past a point in a defined unit of time. This has always been a bit of a sticking point with me and I really cannot understand why Engineers and others continue to use the Current flow , Positive to Negative, when actually it is not what is happening.
+megaohmz Actually that isn't really true, certainly in a free electron metal. The conduction elextrons move in the conduction band and don't leave 'holes'. The solution for the electron on a periodic potential yields Bloch wavefunctions, and when the electrons are almost completely free (as in a metal) you get a continuous conduction band. Current flows with the electrons, as that is what current is. The concept of holes makes more sense with semiconductors when the electrons are not free, and the quantum mechanics gives band gaps.
Like Richb313 I find the current flow method confusing too.
Went through CTM "A" school in the late '90's and we were taught Electron flow is negative to positive, we were also taught "Hole Theory," as it pertained to semiconductors. It was what was deemed the "I believe" section of training. We were also taught "Current Flow," as it made tracing "signal flow" through the circuit easier...but it was stressed that "current flow" was not how the electrons actually moved. I think most people use the "current flow" method to explain circuits, as it makes it easier to relate "signal flow," but few stress the actual electron flow is negative to positive.
Before the discovery of the electron, the early pioneers of electrical and electronic theory did not know what current actually was, or which way it was flowing. There was a meeting and it was arbitrarily decided that it flows from positive to negative. By the time it was discovered that it is in fact electrons flowing from negative to positive, so much electrical and electronic engineering had been based on 'conventional' current that it was impractical to change. From personal experience, it is not difficult to think in terms of whichever system is more appropriate for the subject. E.g. electron flow to understand a vacuum tube, and conventional current to understand a preamp stage.
thanks for clearing that up! another arbitrary decision we all have to live with
That 12AX7 looks bigger on video than it does in person! LOL
Thanks!! Keep up the Good Info. Work on the Audio Quality, though. It's a bit 'Shear'. Just for Positive Feedback.
thank you
Thank you.
It's really a bummer that there is no follow up to this video. This is exactly the sort of step by step I've been looking for as a newbie, and unfortunately it's only partial.
We are on the case with that & hope to up for early 2015 very basic & easy step by step...
Vintage-Audio-Workshop If you are still working on it, Just a suggestion but a rather realistic one..... It would be nice to see something like this but also to get out a real schematic such as a Fender, Vox, Marshall, etc. and go through the circuits, identifying them and pointing out the differences in components used and why. I have been studying as best I can and can almost identify the different parts but how different values affect tone, is still eluding me. In essence a complete tutorial on how tube amps work would be very helpful to us solid state guys. :-D A monumental task, to be sure but WOW, what a help for us beginners.
A grade video on tubes but i would have enjoyed to be looking at diagram right way up.
I have a couple of questions. Why are you running the tube at such a high plate voltage if this is a 12 series tube? Aren't they happy with a 12 volt power supply? Also, how would I get a better bass response out of the distortion channel of my solid state Randall Warhead? Thanks.
the "12" in the its "name" e.g. 12AX7 is for the filament, the heater, not the plate voltage.
To operating a tube you need three voltage souces.
One for the filament, the heater, as tube needs some heat to produce free "flying" electrons. The do have to come out somewhere, and that´s the heater.
Next is the plate voltage, no plate voltage no amplification. As the electrons comes out of the filament (=kathode) they need to know how to go....that´s the plate, so to let the electrons know their way, apply a high voltage at the anode and the electrons will go there....
And this leads us to the third voltage, the grid bias voltage. When applying a high voltage at the anode, all electrons where called to fly to the anode....but the anode is not able to take them all together at the same time. Doing so will simply melt down the metal plate which forms th anode. So the flew of the electrons need to be controlled. This
is what the grid does. Making the grid negative the electron stream is bekomming lower...here is the control function...
Hope that helps...;)
12 volts at 150 MA is for the heater only. The high voltage is for the plate. Less than 100 Volts on the plate is not enough.
hello.
Great video.
Thank you.
Thanks for this very informative video..
I wish that this was done on a white board so it was easier to absorb. Other than that, thank you.
A sensible tutorial on valves (tubes) for a change, with a logical approach that won't result in my being burnt to death, electrocuted to death, or getting AIDS.
nice informative video, thanks
Damn your good !!!!!!! :)
Interesting
veja
Very clear explanation thank you. Back to bench
Very good however the cathode bypass increases gain but also increases distortion. There is a trade off here
🙋♂️🤝👍
Damn
He really left ALL y'all hanging on comment questions LMAO
Current flows from negative to positive.