Vacuum Tubes

[Hi-Fi-Mogul]

I'm starting this topic with noting this nice treatise from
1960, a book titled: Getting the Most Out of Vacuum Tubes.

I'm sure there are many contributions from you guys
to come on vacuum tubes.

I'll have some more as I organize my thoughts.

The link I tried to post was not accepted, but do a search
for the title, and the link will work.

[electra225]

What kind of issue did you have trying to post a link? Did the system give you an error message? Or was the link not right somehow? If it's something I can fix, I'd be happy to take a look and see what I could do. As far as I know, I have the system set to accept all the attachments.

[Hi-Fi-Mogul]

What kind of issue did you have trying to post a link? Did the system give you an error message? Or was the link not right somehow? If it's something I can fix, I'd be happy to take a look and see what I could do. As far as I know, I have the system set to accept all the attachments.

Here is the link to the book pdf. It is working here now.

http://nutshellhifi.com/library/MostVacuumTubes.pdf

BTW, I tried to edit my first post, and could not find
an edit button to use.
Is there a time limit on edits ?
Thanks !

[William]

Thank you, and the link worked for me.

Bill

[electra225]

Mogul, there is a little square box on the upper right hand corner of each post with a crayon symbol in it. The first box, actually. That is the "edit" icon. There is a 30 minute time limit on edits. If you will run your cursor over those boxes, they will be identified.

[Hi-Fi-Mogul]

Mogul, there is a little square box on the upper right hand corner of each post with a crayon symbol in it. The first box, actually. That is the "edit" icon. There is a 30 minute time limit on edits. If you will run your cursor over those boxes, they will be identified.

Thanks, Greg.
I saw the edit button, on posting another topic, and the 30 min edit window.

[Hi-Fi-Mogul]

It is necessary to understand how vacuum tubes' parts are named,
what their function is, and how the vacuum tubes' pins are
conventionally numbered. Tube pin numbers are essential to
reading a tube circuit schematic's wiring.

Tubes have different types of bases through which the pins are
attached to the internal parts of the tube. The base name may refer to
the number of pins of the tube.

Here are links to the Navy Electricity and Electronics Training Series (NEETS),
a 1975 RCA Receiving Tube Manual, and Frank's Electron Tube Data Sheets.

Module 6 of NEETS addresses a full background on vacuum tubes,
electron tubes, or thermionic emission "valves". All refer to the same thing.

When you see a circuit with the tube listed as part "V6", for example, that
is a holdover from the very early days of tube development.
Valve was a term coined by British researchers for a vacuum tube.

The RCA tube manual will contain most all tubes encountered in use.
It has the tube's pin out diagram and information on each tube's use
and performance characteristics.
It also has ancillary info such as replacement guides for
obsolete/hard to find tubes.

Frank's Data Sheets is a very convenient quick tool for finding
tube data, as you would find in the RCA manual.

https://archive.org/details/RCA_RC-30_1975

https://archive.hnsa.org/doc/index.htm#neets

https://frank.pocnet.net/

[Motorola minion]

Pulling tubes from old TVs and other equipment set out for "pick-up" (trash or found outside) was a common practice in the 1970s. :geek:Totally how I got started. Many of these tubes were pulled from radios and console stereos, even TV-stereo combinations. These are of interest to the high fidelity crowd regardless of where it was used initially. For example, 6V6 GT and other audio output tubes were used in electronic organs and older car radios. 6BQ5, 6CG7, 6AU6 and 12AU7 was used in many pre-1970 televisions.

Many drug, tire/auto and hardware stores including service shops sold tubes over the counter. Liquidation sales may turn these up. Other times, in-store tube-testers had new-in-box tubes in the locked cabinet part underneath. Unfortunately many tubes saved this way were not as popular, as the troublesome ones sold out. Some shops saved borderline but functional tubes in order to repair used sets that were sold for a fraction of new sets, but barely worth the thin margin made on them.

Box lots of loose and boxed tubes left over from this irresistible pastime are commonly found at ham fests, antique radio swap meets and many "for sale" ads. Unless its a truly "rare bird" like a 6HR6 for example, pricing is competitive. Shop around but please also mention your vacuum tube search anywhere on this forum and you will get some thoughts and opinions.

One of the bigger problems here is that many tubes with weak emission, gas or leakage found their way into boxes that contained the replacement tube. If the tube is not obviously dust-covered, giving a false impression that its a new-old stock (NOS) or new-in-box (NIB). Tubes can be "cleaned up" so they look unused, but painted logos and often the tube number itself is faded or worn off. This rarely happens with a new tube, in its box. Dust is obvious on tubes that are used, bronze-silver getter flashes and black streaks can look like something bad went down but its perfectly normal for many European tubes. But a milky white - flaky getter is a sure sign of a dead tube.

If you are faced with a dilemma when looking for a tube, you may need to consult a substitution guide and the best I have found to date was published by TAB books. The Sams Tube substitution guide is much more common but lacks details you may find important for your equipment when making a substitution.

Edition: 1976, Tab Books
ISBN: 083065870X
ISBN-13: 9780830658701
Pages: 321
Alibris ID: 16521781755

I will leave tube testers, their criteria for "good" and its inherent pitfalls for another member to explain.

[electra225]

There is a lot of good information in this thread, guys. Thank you both so much for sharing this. Information like this is EXACTLY what I had in mind when I started this board.

[hermitcrab]

I heard that one tube site in florida the owner passed away , and his family want nothing to do with the tube business... how many thousands will be dumped due to no interest in them?... sad to think..

[electra225]

I sold Stan a few thousand tubes in 2002. You'd think the family would look for a buyer, even for pennies on the dollar rather than just dumping that stuff. I sold over twenty thousand tubes at my sale and still have 5 thousand or so left.