Recommendation for Good/Easy to Understand Novice Tube Electronic Book

[shadowlight]

I want to learn bit more about how everything works in tube gear and was looking for a good book to read and learn from it.  The ultimate goal is to build some tube amp/preamp after I understand how to read schematics.  Right now reading a schematics is hit of miss for me from what the symbols mean and no clue on what they do.  Here is an example of the schematics that I am trying to understand.

http://www.lyrita-audio.in/circuit_dht%20line%20preamp.pdf

TIA

[richidoo]

Intro to tubes website:
http://www.dhtrob.com/overige/boekwerken_en.php

http://www.vacuumtubes.net/How_Vacuum_Tubes_Work.htm

http://www.ibiblio.org/kuphaldt/electricCircuits/Semi/SEMI_13.html

http://www.tubecad.com/ (hodgepodge)


I own these books, they are pretty good.
Morgan Jones - Valve Amplifiers
Morgan Jones - Building Valve Amplifiers
Bruce Rosenblit - Tube Audio Design

Other books worth checking out:
http://www.elektor.com/fundamental-amplifier-techniques-with-electron-tubes

I will label the sch and try to explain as much as I can. I am not a tube expert. But as long as you know what the part is and basic info you can put together a kit that someone else designs. You'll still need help starting it up.

[richidoo]

Designed for 230VAC mains input (for use in a different country,) so you'll need different power transformers that make the required output voltage from your 120VAC mains.

[shadowlight]

Designed for 230VAC mains input (for use in a different country,) so you'll need different power transformers that make the required output voltage from your 120VAC mains.

Thx Rich.  The one symbol that I did not understand on the schematic was the one in the ripple filter/storage with 150mH (symbol with 4 o/0) that looks like register.

[tmazz]

Designed for 230VAC mains input (for use in a different country,) so you'll need different power transformers that make the required output voltage from your 120VAC mains.

Thx Rich.  The one symbol that I did not understand on the schematic was the one in the ripple filter/storage with 150mH (symbol with 4 o/0) that looks like register.

I am not really familiar with that symbol either, but if it is labeled as 150 mH then it has to be some kind of choke coil, which would make sense given where it is located in the circuit.

[richidoo]

Yup, it's a choke/inductor/coil. The standard symbol for it would be



The bars above the coil signify iron core style inductor, aka choke, this is usually the type used for power supply smoothing. Maybe he drew the bars above and below the coils drawn as circles?

Similar vertical bars signify the iron core in the power transformers, with primary and secondary windings on either side.

[shadowlight]

Thx Tom and Rich 

[tmazz]

Yup, it's a choke/inductor/coil. The standard symbol for it would be



The bars above the coil signify iron core style inductor, aka choke, this is usually the type used for power supply smoothing. Maybe he drew the bars above and below the coils drawn as circles?

Similar vertical bars signify the iron core in the power transformers, with primary and secondary windings on either side.

That is the symbol that I think most of us are used to seeing for a choke coil. I have never seen they symbol shown on that print before, but looking at the circuit it is in I cannot think of what else it could be.

[shadowlight]

I will reach out to the owner of the site and ask but I am 99.9% sure that  it is choke as you guys suspect based on some of the comments made by  current owners.

[richidoo]

Hi Deepak, the parts labels says 3H, 40mA for one, and 150mH for the other. Those are inductor specifications, inductance is stated in units called Henry. 3 Henries, and .15 Henries = 150 milli-Henries, 150mH.

Some chokes suitable for this design would be like these:

http://www.londonpower.com/3h-choke

http://au.element14.com/bourns-jw-miller/70f151af-rc/choke-150mh-44ma-5-77khz/dp/1191777

[richidoo]

A decent article on using choke in DC power supply.
http://www.aikenamps.com/index.php/chokes-explained

Notice he says their purpose is adding current inertia to the circuit, so it's really only useful in tube circuits when the load is steady current draw, like class A amplifier. The current draw from class A amp is always the same, no matter what music is played, quiet or loud, the amp is always turned up all the way, always using maximum possible power, so the current draw is steady and a choke is very effective at smoothing the voltage ripples.

Another article on designing DC power suppies for tube audio. Talks technical about using chokes, caps and resistors to smooth and power various loads.
http://www.valvewizard.co.uk/smoothing.html