• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

On Line Tube Learning for newbies....

For those wanting to see an example of building an amp from load lines to complete chassis, then I would recommend having a look at this very clear article as an example: ...

Interesting, thanks! The placement of the parts on the chassis is a lot more compact than what is considered best practice? This is like a lot of classic amps, maybe it isn't as critical as we are led to believe?
 

NickKUK

Member
2019-12-28 9:16 pm
Interesting, thanks! The placement of the parts on the chassis is a lot more compact than what is considered best practice? This is like a lot of classic amps, maybe it isn't as critical as we are led to believe?

That did occur to me too given tubes radiate more heat than conduct/convection cooling.

I go for a minimum of 1 tube width between them and I go to the extent that I face the the flat face of plates to minimise radiated heat between tubes. Part heater, part disappeared plate heat. You could put tubes in a black radiator tube (ie one with cooling fins that absorbed radiated heat and the allow the air to convey up cooling the heat away).

A matt black chassis will also absorb a lot of heat radiated by the tubes (same with black transformer covers).
 
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Replying to my own post here for a book review after only 1/3 through it. This book is way more than fun, it is the first book that got me to fully understand how gm, u and rp relate and how they can be obtained from a family of plate voltage curves. Also how to make my own curves experimentally. Also how to derive a family of grid voltage curves. Also how to simple transpose a family of plate curves into grid curves. Also how to determine gm, u and rp from a family of grid curves. Also how all these factors come about via the way the tube is constructed. Also how gm, u and rp interact. Also how the space charge works and is interacted upon by the two main force fields in the triode, grid and plate. Also deriving values in AC graphically using a mean point with equal swing. Wow, what an eye opener. Now I know exactly why this book is on the register of most valuable books in electronics. I am going to stop and re-read everything on "static" operation of the triode before proceeding into the next chapter "dynamic" operation. This is all very exciting, I don't know spice, I didn't want to hobby by building from schematics (which is fine), for some reason I needed to learn some first principles then try them out. Out of all the modern tube books that cover characteristics, I've found them all to fall flat in explaining things for a beginner. I highly recommend this book for anyone newbie!
 

TonyTecson

diyAudio Moderator Emeritus
2003-05-29 2:57 am
Maybunga, Pasig City
Replying to my own post here for a book review after only 1/3 through it. This book is way more than fun, it is the first book that got me to fully understand how gm, u and rp relate and how they can be obtained from a family of plate voltage curves. Also how to make my own curves experimentally. Also how to derive a family of grid voltage curves. Also how to simple transpose a family of plate curves into grid curves. Also how to determine gm, u and rp from a family of grid curves. Also how all these factors come about via the way the tube is constructed. Also how gm, u and rp interact. Also how the space charge works and is interacted upon by the two main force fields in the triode, grid and plate. Also deriving values in AC graphically using a mean point with equal swing. Wow, what an eye opener. Now I know exactly why this book is on the register of most valuable books in electronics. I am going to stop and re-read everything on "static" operation of the triode before proceeding into the next chapter "dynamic" operation. This is all very exciting, I don't know spice, I didn't want to hobby by building from schematics (which is fine), for some reason I needed to learn some first principles then try them out. Out of all the modern tube books that cover characteristics, I've found them all to fall flat in explaining things for a beginner. I highly recommend this book for anyone newbie!


the datasheet specs and curves will give a lot of information you will ever need...
 

nzoomed

Member
2015-08-12 11:06 pm
There is quite alot to learn in this area.
I have no degree in electrical engineering, but I started out with guitar amps. Its easy to start out with those, because something that sounds good for a guitar is likely going to be bad for hi-fi, but you can get used to experimenting with swapping component values and see what part of the circuit does when modified, etc.
Adding negative feedback, etc will show you the basics of a tube amp. But thats where it ends, Hi-fi is all about getting the signal through with the least amount of distortion or other alteration of the signal from the source.
I would like to learn more on this, but ive really only got to the point of looking at curves on the datasheets for tubes, there is so much else you need to know about impedances, time constants for cathode bypass capacitors, etc, etc :p
I guess the basics are really about calculating correct load resistors, coupling caps, etc and then work from there.
 
Where did you find those modules? In the introduction I see some very interesting modules which I would like do download.
  • Module 1 - Matter, Energy, and Direct Current (Jun 2011)
  • Module 2 - Alternating Current and Transformers (Mar 2012)
  • Module 3 - Circuit Protection, Control, and Measurement (Feb 2013)
  • Module 4 - Electrical Conductors, Wiring Techniques, and Schematic Reading (May 2013)
  • Module 5 - Generators and Motors (Sep 2011)
  • Module 6 - Electronic Emission, Tubes, and Power Supplies (Mar 2012)
  • Module 7 - Solid-State Devices and Power Supplies (Aug 2012)
  • Module 8 - Amplifiers (Feb 2013)
  • Module 9 - Wave-Generation and Wave-Shaping Circuits (Jul 2012)
  • Module 10 - Wave Propagation, Transmission Lines, and Antennas (Jul 2012)
  • Module 11 - Microwave Principles (Feb 2012)
  • Module 12 - Modulation (Jan 2012)
  • Module 13 - Number Systems and Logic Circuits (Jan 2012)
  • Module 14 - Inroduction to Microelectronics (Sep 2003)
  • Module 15 - Principles of Synchros, Servos, and Gyros (Dec 2012)
  • Module 16 - Test Equipment (Apr 2013)
  • Module 17 - Radio-Frequency Communications Principles (Apr 2013)
  • Module 18 - Radar Principles (Apr 2013)
  • Module 19 - The Technician's Handbook (Jan 2004)
  • Module 20 - Master Glossary (Jan 2004)
  • Module 21 - Test Methods and Practices (May 2013)
  • Module 22 - Digital Computing (May 2013)
  • Module 23 - Magnetic Recording (May 2013)
  • Module 24 - Fiber Optics (Jun 2014)

http://www.compatt.com/Tutorials/NEETS/NEETS.html