Good (more or less) introductory vacuum tube information references

mhardy6647

This kind of, sort of came up in another discussion recently.

http://forum.polkaudio.com/discussion/181256/50-watt-amp-with-5-distortion-only-149-000-interested

In the above mentioned thread, I mentioned a short primer called A Taste of Tubes. Tis is an excellent place to start, especially if all one knows about tubes is that they're... umm... tubular. Maybe one also knows they're called "valves" in the UK, too
Here's a link to a copy of this primer: http://ken-gilbert.com/images/pdf/taste_of_tubes.pdf

I felt like I'd hijacked that thread enough, so I figured I'd start another one

This thread is meant for anyone who is interested in the nuts and bolts of how vacuum tubes do what they do and how they're applied - traditionally - in hifi audio circuits.



ok, now... first and foremost: kudos to pro hifi designer Pete Millett, who also shares much of his skill with the DIY crowd, too, at his wonderful site http://www.pmillett.com

Pete also has gone to great length to scan scads of books and other reference material that is invaluable to DIYers and folks generally interested in audio circuit design and construction, particularly in the realm of the aforementioned vacuum tubes.

That site is www.tubebooks.org

Now -- to the subject of this post!

Here are a few suggestions of sort of basic books on vacuum tubes that you can download from Pete's site. I am going to provide links to the tables of contents to the books; the descriptions are from www.tubebooks.org

Basic Theory and Applications of Electron Tubes, Departments of the Army and Air Force, 1952, 215 pages

This is an excellent, relatively modern (1952) text on vacuum tubes. Very practical, not too much math, and it has some very nice illustrations. Very specific to tubes, discusses how they work, how they're built, and circuits.

link to TOC: http://www.tubebooks.org/Books/intro_army_theory.pdf
link to whole PDF: http://www.tubebooks.org/Books/army_theory.pdf

Inside the Vacuum Tube, John F, Rider, 1945, 407 pages- Courtesy of Earles McCaul

One of my new favorites - this is a fabulous book on how tubes work and how to design tube circuits. this is NOT a college text; rather this is written more at the level of an advanced technician, with not so much math and lots of diagrams that make visualizing what's going on easy. It even has some 3-D drawings - you'll need anaglyph (red/blue) 3-D glasses to view them.

link to TOC: http://www.tubebooks.org/Books/intro_rider_inside.pdf
link to whole PDF file: http://www.tubebooks.org/Books/rider_inside.pdf

Radio Receiving and Television Tubes, James Moyer, 1936, 645 pages - Courtesy of Walter Welch, AI4SP!

A comprehensive text on tubes, how they're made, how they work, and applications circuits. Covers tube testers in some detail, as well as early television circuits.

link to TOC: http://www.tubebooks.org/Books/intro_moyer_radiotubes.pdf
link to PDF: http://www.tubebooks.org/Books/moyer_radiotubes.pdf

Pete's site doesn't have a huge amount of bandwidth, so it'll take a while to d/l the files, but this is an incredible resource for -- well, folks who are interested in stuff like this!

verb

Very cool gesture doc @mhardy6647 ! Tubes 101. I look forward to this semester!

kharp1

Thanks for the good info, much appreciated. I'm an electrician (more a civilian trapped in an electricians body) but the tube is not something we studied much in class, and, definitely not in the work environment. There is a learning curve with valve, but, it's been enjoyable. For me, nothing has changed my love for audio equipment more than tubes. The difference in sound is dramatic.

I'm interested in any educational material you can provide.

tonyb

Educational material ??

Here's all ya need to know pal.....

Buy lots of tubes....listen, buy more....repeat.

What else ya need to know ??

Brock has that system down pat.

kharp1

You know man, like, I want to know what the electrons are doing you know, man.

mhardy6647

kharp1 wrote: »

You know man, like, I want to know what the electrons are doing you know, man.

https://youtu.be/JUOGxePBs50

pitdogg2

tonyb wrote: »

Educational material ??

Here's all ya need to know pal.....

Buy lots of tubes....listen, buy more....repeat.

What else ya need to know ??

Brock has that system down pat.

True dat lol

pitdogg2

kharp1 wrote: »

You know man, like, I want to know what the electrons are doing you know, man.

They flow what more is there to know

FestYboy

Thank you @mhardy6647, that's fantastic. Just the type of info to really get my learn on.

mhardy6647

DSC_0128 by Mark Hardy, on Flickr

nooshinjohn

pitdogg2 wrote: »

kharp1 wrote: »

You know man, like, I want to know what the electrons are doing you know, man.

They flow what more is there to know

Does this have anything to do with the Fluid Dynamics course discussed in another thread?

FestYboy

mhardy6647 wrote: »

DSC_0128 by Mark Hardy, on Flickr

That's perdy

verb

mhardy6647 wrote: »

DSC_0128 by Mark Hardy, on Flickr

Awesome! What kind of material is used for the plate? Why the holes? To modify the shape of the space charge? Or heat dissapation?

Ahem, yes up to chapter 3!

mhardy6647

Perforated metal -- sort of a cheap (relatively speaking) way of doing a mesh plate.
I really don't know why mesh plates have a certain -- cachet, to tell you the truth.

verb

mhardy6647 wrote: »

Perforated metal -- sort of a cheap (relatively speaking) way of doing a mesh plate.
I really don't know why mesh plates have a certain -- cachet, to tell you the truth.

Bling factor! Unintended consequence at the time of industry application I'm sure!

mhardy6647

that perforated plate "Sofia" (Chinese-made) branded "2A3" (actually more like a 300B with a 2.5 v filament) is certainly bling-y; sort of the 1974 Eldorado of DHTs.

I prefer the vintage 2A3 look -- but those goofy looking things do sound good.

oh, for anyone not used to playing in this sandbox -- "DHT" = direct heated triode. The filament and cathode are one in the same. Most "modern" (it's all relative!) tubes have a separate heater and an indirectly heated cathode.

The 2A3, as best I know, has been around since the 1930s -- and also as far as I know has been in production continuously since it was introduced.



Here's a more typical, vintage double-plate 2A3.




The earliest 2A3s were single-plates. Reputed to be the sweetest-sounding of all 2A3s, but not terribly common and pretty darned expensive. I do have one.

2A3sp n box by Mark Hardy, on Flickr

verb

Hard to tell from the pic of the double plate 2A3 @mhardy6647, but what kind of grids are in there? Oval Helix? What are the advantages of a double plate? Are they interchangeable with the single plate?

mhardy6647

Dual plate 2A3 can dissipate twice the power of a single plate tube. The single plate has a more magical presentation, though.


... and then there's the famous 45 DHT. Only 2.2 watts of output, but arguably the most soulful of all the DHTs.

The 46, an interesting dual-grid tube (so technically not quite a triode, although also DHT) is only capable of about 1.3 watts, but also quite sublime -- and cheaper than a 45 on today's market.

verb

mlistens03

I've been wanting a tube amplifier for a while, anyone know of good models to get me started? I have never looked at tubes before other than the monoprice, so I don't know much about them.
Thanks @mhardy6647 for this, I will read it later when I have more time

mhardy6647

mlistens03 wrote: »

I've been wanting a tube amplifier for a while, anyone know of good models to get me started? I have never looked at tubes before other than the monoprice, so I don't know much about them.
Thanks @mhardy6647 for this, I will read it later when I have more time

Where do you live (regionally speaking)?
If you're anywhere near northern New England, I have a "lending library" of things that might be worth a try There are probably other like-minded enablers hanging around here, looking for new converts!

It's a harder question to answer than you might think.
Do you want current production or vintage? In the latter case, any interest in doing restoration yourself? I am guessing "no".

What speakers do you want to use it with and how much money do you want to spend?

nooshinjohn

I welcome anyone looking at tube amps to drop by my place and give them a listen.

FestYboy

Road trip!!