## About

Some people have made the mistake of expressing interest in electron
tubes. They're about to learn more than they bargained for.

## News

The first session was a great success. We covered the first item in the
syllabus and part of the second.

The next session will feature a brief review of the first session and
finish covering the second section. I think it should be possible to
reach the section on advanced circuits. during the next session.

I also owe you guys a tube dissection, I'll try to work that into the
next session too.

## Schedule

Next class: Aug 11 at 7:30 PM.

## Silly Bus

- Thermionic emission: From the lightbulb to the pentode.
- Fundamental circuits and coupling
- Push-pull and Phase splitting circuits
- Transformers in single-ended and push-pull.
- Advanced circuits
- Tube failure modes

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- Hands-on experience building a battery-powered single tube filamentary
  pentode pre-amp.

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- Power supplies and tweaking.

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- What is the real secret to great sound?

### Laboratory Supplies

[cheap demo
pre-amp](http://www.bottlehead.com/store.php?crn=220&rn=438&action=show_detail)

Go to \[tubedata.info\] and obtain what you think is the most
informative datasheet for the following tubes and print out a copy. --
you need a physical copy.

**filamentary diode** 5U4\* Optional: GZ34 / 5AR4

**canonical triode** 2A3 Optional: 845

**to explore gain versus output** 6SN7\* 6SL7\* or 12AX7 / ECC83

**Pentodes** 6BQ5 / EL84 Optional: KT88, EF86

3S4 \<\<\< absolutely required, this is the tube we're using.

### Suggested Reading

Radiotron Designer's Handbook 4th ed. \[www.pmillett.com\] Might have
one lying around.

Tube Circuits for Audio Amplifiers (1-882580-03-6) features some very
elegant and practical designs.

An Approach To Audio Frequency Amplifier Design. (1-882580-05-2) Has
some good discussions about output transformers and ultralinear design.
Then it starts out with some nice practical amps but, before long at
all, starts talking about 1,100 watt monsters with 2.5KV power supplies.

Building Valve Amplifiers (0-7506-5695-6) is probably too practical to
be enjoyable but I have to deem it essential. His other book is
fantastic, one of the most well worn tomes in my personal library, but
get this one first.

[Category:Classes](Category:Classes "wikilink")