Hello, I need some sort of push in the right direction. You see, I want to learn how to build, DIY projects that uses vacuum tubes. The folks here seems to be the experts at VT, so I'm throwing this question here.
I'v been reading the RCA receiving tube manual and looking for cheap kits... So far, the S5 amplifier seems to be the most cheapest true-tube/high voltage design out there. I might get this kit to play with.
My background: I'm not new to electronics and DIY. But all my life, I've built either discrete or IC based electronic projects. ... mostly audio stuff, preamp, mic preamp, amp, EQ, that stuff. Now, I want to venture to Vacuum tubes.
Questions:
1. When reading a VT schematic, I've come to the conclusion that you need to know the pin #s of the plate, grid, heater, etc of a particular tube model.... and this is where the RCA manual comes in handy. Right?
2. Knowing the right pin #, I can now do point-to-point wiring??? Is that right?
3. The RCA manual sometimes lists RC components for some of its design (in a table format)... but no voltage ratings (for caps) and wattage (for resistors) are given. If the B+ is say 300V, can I just use 450V rated caps, or should I go 2x at 600V? Should I use 2W for all resistors to be on the safe side?
4. How dangerous *really* are these voltages. IF you make a mistake (i.e. brushed them or touched them accidentally), would you instantly die? I mean, the amperage are very small. (Not that I'm planning on touching them, but I need confidence in this area)
5. Is it safe to poke around with an oscilloscope? Or is there some sort of adapter/protector I must use in my scope before I start poking around?
6. Typically, how much would the power transformers cost... i.e. 300V secondary, 6.3V, etc... what is the price range?
7. Any good VT books you can recommend for a total newbie like me? ...sort of equivalent to Dummies book. That's my knowledge of VT... zero. I'm more comfortable around transistors and solid states.
That's all for now. Thanks in advance!
Owel
I'v been reading the RCA receiving tube manual and looking for cheap kits... So far, the S5 amplifier seems to be the most cheapest true-tube/high voltage design out there. I might get this kit to play with.
My background: I'm not new to electronics and DIY. But all my life, I've built either discrete or IC based electronic projects. ... mostly audio stuff, preamp, mic preamp, amp, EQ, that stuff. Now, I want to venture to Vacuum tubes.
Questions:
1. When reading a VT schematic, I've come to the conclusion that you need to know the pin #s of the plate, grid, heater, etc of a particular tube model.... and this is where the RCA manual comes in handy. Right?
2. Knowing the right pin #, I can now do point-to-point wiring??? Is that right?
3. The RCA manual sometimes lists RC components for some of its design (in a table format)... but no voltage ratings (for caps) and wattage (for resistors) are given. If the B+ is say 300V, can I just use 450V rated caps, or should I go 2x at 600V? Should I use 2W for all resistors to be on the safe side?
4. How dangerous *really* are these voltages. IF you make a mistake (i.e. brushed them or touched them accidentally), would you instantly die? I mean, the amperage are very small. (Not that I'm planning on touching them, but I need confidence in this area)
5. Is it safe to poke around with an oscilloscope? Or is there some sort of adapter/protector I must use in my scope before I start poking around?
6. Typically, how much would the power transformers cost... i.e. 300V secondary, 6.3V, etc... what is the price range?
7. Any good VT books you can recommend for a total newbie like me? ...sort of equivalent to Dummies book. That's my knowledge of VT... zero. I'm more comfortable around transistors and solid states.
That's all for now. Thanks in advance!
Owel
Let me try to attack a few of them:
1. The tube manual (data sheets in general) is indeed invaluable for this. It's also going to be your best friend once you start playing around with designing.
2. Yes.
3. You can generally figure out the voltage and dissipation ratings by drawing out the schematic and seeing what voltages to expect. For coupling caps, at least 1.5x the B+ voltage is a good idea. Two times is even better. 2W resistors in the plate circuits will work most of the time, but again, a few minutes with the schematic and Ohm's Law will get you the answers you seek. Grid resistors can generally be much smaller than plate resistors.
4. EXTREMELY. I wouldn't even CONSIDER working on tube circuits without experienced supervision your first few times through. Death is quite permanent, and among the ways to die, this is among the worst.
5. Subject to the caveat above, you'll want scope probes rated appropriately to the voltages you're looking at.
6. You're on your own here!
7. Assuming you've got a good grasp of Ohm's and Kirchoff's laws, I'd recommend Morgan Jones's book.
1. The tube manual (data sheets in general) is indeed invaluable for this. It's also going to be your best friend once you start playing around with designing.
2. Yes.
3. You can generally figure out the voltage and dissipation ratings by drawing out the schematic and seeing what voltages to expect. For coupling caps, at least 1.5x the B+ voltage is a good idea. Two times is even better. 2W resistors in the plate circuits will work most of the time, but again, a few minutes with the schematic and Ohm's Law will get you the answers you seek. Grid resistors can generally be much smaller than plate resistors.
4. EXTREMELY. I wouldn't even CONSIDER working on tube circuits without experienced supervision your first few times through. Death is quite permanent, and among the ways to die, this is among the worst.
5. Subject to the caveat above, you'll want scope probes rated appropriately to the voltages you're looking at.
6. You're on your own here!
7. Assuming you've got a good grasp of Ohm's and Kirchoff's laws, I'd recommend Morgan Jones's book.
Hi,
You'll be too busy with the kids/kits, Peter 😉
OTOH...What took you so long???😀
Owel,
1/ A manual with tube specs, doesn't have to be RCA, is a must have especially when you want to work offline.
2/ Correct.
3/ No, here's where you'll need Ohm's law, loadlines, learn how to bias the grid of the tubes and sometimes even more complicated stuff.
4/ Very. Lethal in most cases in fact. This has been discussed extensively here, there must be a sticky thread about safety issues at the top of this page about this, I think.
5/ I'm no scope jockey. I'll leave that to the guys that do that on a daily basis, I don't.
6/ Check at vendors such as Hammond, perhaps?
7/ Is there a Tubes for Dummies? Dunno. There are some websites with the basic things you need to know though.
I'll try and post a document compiled by one of our members and post it in your thread later on.
Cheers and welcome,😉
EDIT: Dang, SY....you beat me to it...😉
You'll be too busy with the kids/kits, Peter 😉
OTOH...What took you so long???😀
Owel,
1/ A manual with tube specs, doesn't have to be RCA, is a must have especially when you want to work offline.
2/ Correct.
3/ No, here's where you'll need Ohm's law, loadlines, learn how to bias the grid of the tubes and sometimes even more complicated stuff.
4/ Very. Lethal in most cases in fact. This has been discussed extensively here, there must be a sticky thread about safety issues at the top of this page about this, I think.
5/ I'm no scope jockey. I'll leave that to the guys that do that on a daily basis, I don't.
6/ Check at vendors such as Hammond, perhaps?
7/ Is there a Tubes for Dummies? Dunno. There are some websites with the basic things you need to know though.
I'll try and post a document compiled by one of our members and post it in your thread later on.
Cheers and welcome,😉
EDIT: Dang, SY....you beat me to it...😉
Hi Owel,
Welcome to a fascinating avocation, where
you can create wonderful amps (relatively)
cheaply from simple designs, and spend a
lifetime learning the subtleties.
You are in fine hands with Frank and SY,
and let me add just a couple of things:
1. An indispensible online tube reference is:
http://tdsl.duncanamps.com/tubesearch.php
4. Unfortunately, the safety thread is *not* on
this page. 🙁 Here it is:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=30172
(in case the link doesn't work, it's in the Everything Else forum.
7. I started with Morgan Jone's book (Valve Amplifiers,
I'm looking at it) too, and recommend it. Excellent
as it is, it unavoidably skips over some stuff, and
I find myself collecting books (and loving it).
Check out audioXpress.com for a great selection,
and do not miss their Audio Classroom articles:
http://www.audioxpress.com/resource/audioclass/
They are an excellent introduction. If you take
your time and absorb those articles, you will
be well on your way. Besides, they're free
(one of my favorite words), and you can start
right now. 😀
Also, check out the FAQ over at AudioAsylum.com
It's Tubes section has some links to great intros,
including how a tube works and stuff.
Welcome, be safe, and have fun.
Best,
George "I Loves Me Some Tubes" Ferguson
Welcome to a fascinating avocation, where
you can create wonderful amps (relatively)
cheaply from simple designs, and spend a
lifetime learning the subtleties.
You are in fine hands with Frank and SY,
and let me add just a couple of things:
1. An indispensible online tube reference is:
http://tdsl.duncanamps.com/tubesearch.php
4. Unfortunately, the safety thread is *not* on
this page. 🙁 Here it is:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=30172
(in case the link doesn't work, it's in the Everything Else forum.
7. I started with Morgan Jone's book (Valve Amplifiers,
I'm looking at it) too, and recommend it. Excellent
as it is, it unavoidably skips over some stuff, and
I find myself collecting books (and loving it).
Check out audioXpress.com for a great selection,
and do not miss their Audio Classroom articles:
http://www.audioxpress.com/resource/audioclass/
They are an excellent introduction. If you take
your time and absorb those articles, you will
be well on your way. Besides, they're free
(one of my favorite words), and you can start
right now. 😀
Also, check out the FAQ over at AudioAsylum.com
It's Tubes section has some links to great intros,
including how a tube works and stuff.
Welcome, be safe, and have fun.
Best,
George "I Loves Me Some Tubes" Ferguson
I second the duncanamps.com recommendation. Download the database software and the power supply designer- incredibly useful.
As for safety, start with low voltage projects first. 250V won't kill ya, 400V still unlikely, 1000V pretty likely.
For caps use a decent margin, eg 450V caps for a 350V project.
Wattage for resistors- just find how much voltage they are dropping, divide by the resistance to get current, times the current by the voltage drop to get power dissipated. Make the resistor 50-100% bigger power rating.
As for safety, start with low voltage projects first. 250V won't kill ya, 400V still unlikely, 1000V pretty likely.
For caps use a decent margin, eg 450V caps for a 350V project.
Wattage for resistors- just find how much voltage they are dropping, divide by the resistance to get current, times the current by the voltage drop to get power dissipated. Make the resistor 50-100% bigger power rating.
Incorrect: 250v can easilly make you (permanently) dead.
But Shifty's sentiments are correct: The lower voltage projects are lower risk.
Brushing past high voltages is unpleasant, but you are more likely to damage yourself from the muscular reaction, that from electrocution.
**The golden rule, is to keep one hand behind your back, or in your pocket**
Such things as insulated shoe soles, and non-metalic bench, are essential for any electronic testing.
I too recommend Morgan Jones Valve Amplifier books.
Cap ratings: SY says 1.5x +B. That's correct unless a reactive load such as a choke is used, then go for 2.5x. Also, cathode bypass cap ratings should be calculated individually.
Resistor values: we often use higher wattage resistors, not for the power dissapation, but for their higher voltage rating.
In addition to Jones' writings, Principles of Power by O'Connor and Basic Electronics for Scientists by Brophy are good references.
If you understand FET circuitry, you have the beginnings of understanding tubes. FETs, like tubes, are voltage controlled high impedance devices. The characteristic curves of FETs and pentodes are remarkably similar in appearance.
The warning about working with only 1 hand can't be over emphasized. Even with careful work habits, an occasional shock will occur. In the hand, a shock is UNPLEASANT. A shock across the heart can be, and frequently is, deadly.
BTW, people UNDERESTIMATE the danger of SS equipment. A 200 W. SS power amp has rail voltages > 40. Several Amperes at 40+ V. can easily burn you very badly.
If you understand FET circuitry, you have the beginnings of understanding tubes. FETs, like tubes, are voltage controlled high impedance devices. The characteristic curves of FETs and pentodes are remarkably similar in appearance.
The warning about working with only 1 hand can't be over emphasized. Even with careful work habits, an occasional shock will occur. In the hand, a shock is UNPLEASANT. A shock across the heart can be, and frequently is, deadly.
BTW, people UNDERESTIMATE the danger of SS equipment. A 200 W. SS power amp has rail voltages > 40. Several Amperes at 40+ V. can easily burn you very badly.
Thanks!
Excellent replies. A very big thanks to all.
I've bookmarked the sites and links you've given and will start reading them. I subscribe to Audioxpress, and sometimes visit their website. I'm surprised I didn't see their free VT tutorials (their website can be confusing to navigate sometimes).
>Morgan Jones's book
What is the complete title of this book? Valve Amplifiers?
>BTW, people UNDERESTIMATE the danger of SS equipment.
Funny story, when I was 16 (many decades ago) I was trying to check how my DIY SS amp was doing, checking for heat, and with moist hands I reached in the back and put my two fingers on the case (i.e. the collectors) of the NPN and PNP power transistor. I got a SHOCK there!
I'll come back again for more questions. Thanks.
Excellent replies. A very big thanks to all.
I've bookmarked the sites and links you've given and will start reading them. I subscribe to Audioxpress, and sometimes visit their website. I'm surprised I didn't see their free VT tutorials (their website can be confusing to navigate sometimes).
>Morgan Jones's book
What is the complete title of this book? Valve Amplifiers?
>BTW, people UNDERESTIMATE the danger of SS equipment.
Funny story, when I was 16 (many decades ago) I was trying to check how my DIY SS amp was doing, checking for heat, and with moist hands I reached in the back and put my two fingers on the case (i.e. the collectors) of the NPN and PNP power transistor. I got a SHOCK there!
I'll come back again for more questions. Thanks.
that's funny sy... how the hell did you find that???
while speaking of morgan jones, i too recomend this book. it is excelent value for it's price too, and it contains a lot of useful and invaluble information.
go to www.duncanamps.com and go to the software section. download the tdsl personal edition, and this will give you all the pinout info you need, as well as a small amount of data, in most cases a few operating points and max ratings, and it also gives links to full blown data sheets. I have this program and i can't recomend it enough.. it is VERY handy!!! This will give you pinouts and max ratings at the least while offline which is all you'll need while you're just starting out... once you start designing amps yourself, then you might want to get hold of a good tube manual, although, i just use online data sheets still... but i am planning on buying a tube manual soon as this will make it much easier on me... but i am waiting until my financial resources alow for it...
later
while speaking of morgan jones, i too recomend this book. it is excelent value for it's price too, and it contains a lot of useful and invaluble information.
go to www.duncanamps.com and go to the software section. download the tdsl personal edition, and this will give you all the pinout info you need, as well as a small amount of data, in most cases a few operating points and max ratings, and it also gives links to full blown data sheets. I have this program and i can't recomend it enough.. it is VERY handy!!! This will give you pinouts and max ratings at the least while offline which is all you'll need while you're just starting out... once you start designing amps yourself, then you might want to get hold of a good tube manual, although, i just use online data sheets still... but i am planning on buying a tube manual soon as this will make it much easier on me... but i am waiting until my financial resources alow for it...
later
i just went and looked at the audioXpress site... and without even reading the articles, i can already tell you that they will be very good... Norman Crowhurst is one of the truly great mind's to have researched vacuum tube technology, and not only was he an amazing engineer, his way of explaining things (from what i've read of his), is fairly easy to understand considering, because he also has a good way of comunicating with the written word. I have read quite a lot of papers by Norman, and i consider him to be truly great.
cheers
cheers
You are very welcome.
Heartily agreed.
I only found the Audio Classroom articles because Bandersnatch send me a link. Even when I'm looking for something I've already seen there, I can't find it--and have to resort to Google to find it.
(tip-- when Googling, add the site:sitename.com command
to your search string to limit results to that particular site.
e.g. "site:audioxpress.com audio classroom")
A case in point--Norman Crowhurst's "Understanding Hi-Fi Circuits" book is highly recommended, and I find it impossible to find using AudioXpress's navigation. Thanks to google, here's the link:
http://www.audioxpress.com/bksprods/books/bkaa63.htm
Rant off! 😉
Welcome, have fun, and be safe!
Best,
George "Enthusiastic Amateur" Ferguson
My own copy of Crowhurst's UHFC is tattered, stained, and worn- a good sign. But it's not a good introduction, it's better to read once you've got a solid understanding of the basics of tube operation.
Hi SY,
At our advanced age, isn't everything we have tattered, stained, and worn?
But your point is well taken--I have not yet read UHFC, and shouldn't have given the impression I was recommending it as a primer.
BTW, the source of the quote you were guessing at is "Army of Darkness". Classic.
Best,
George "And This Is My BOOM Stick!!!" Ferguson
At our advanced age, isn't everything we have tattered, stained, and worn?
But your point is well taken--I have not yet read UHFC, and shouldn't have given the impression I was recommending it as a primer.
BTW, the source of the quote you were guessing at is "Army of Darkness". Classic.
Best,
George "And This Is My BOOM Stick!!!" Ferguson
Thanks- didn't know AoD at all.
A lot of Crowhurst's articles are now on line at various sites. They should be read and understood by anyone who's even half-serious about tube design.
A lot of Crowhurst's articles are now on line at various sites. They should be read and understood by anyone who's even half-serious about tube design.
Another nice tube site with good links, helped me (still does) alot 😉
http://www.funwithtubes.com/
And if everything (place) else fails, always try this one. Will get your answers 😉
http://www.diyaudio.com/forums/forumdisplay.php?forumid=5
http://www.funwithtubes.com/
And if everything (place) else fails, always try this one. Will get your answers 😉
http://www.diyaudio.com/forums/forumdisplay.php?forumid=5
>Another nice tube site with good links, helped me (still does) alot
http://www.funwithtubes.com/
What a coincidence. I have corresponded with Max!!! He's been very helpful and friendly in our email conversations! I like him.
During our email conversations, when he saw my interest in VT, he took one of his copies of RCA Tube Manual and sold it to me. Very pristine condition.
Yes, his site is very helpful.
I think this is a pic of the RCA manual he sold me.
http://www.angelfire.com/electronic/funwithtubes/Philco.html
Did you know the maintainer of this site, Max, is legally blind in one eye... 2% vision.
http://www.funwithtubes.com/
What a coincidence. I have corresponded with Max!!! He's been very helpful and friendly in our email conversations! I like him.
During our email conversations, when he saw my interest in VT, he took one of his copies of RCA Tube Manual and sold it to me. Very pristine condition.
Yes, his site is very helpful.
I think this is a pic of the RCA manual he sold me.
http://www.angelfire.com/electronic/funwithtubes/Philco.html
Did you know the maintainer of this site, Max, is legally blind in one eye... 2% vision.
You're welcome. Someone of your sensibilities should at least give it a look.
(Read into that what you may.
)If you ever see any of his articles on advanced ouput stages--unity-coupled, etc.-- online, please let me know. Or by anyone else, for that matter. I have been unable to find any of the seminal unity-coupled articles, by McIntosh, et. al., online.
Best,
George "Shop Smart, Shop S-Mart!" Ferguson
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