rectifier into 5U4?

[Lindsay Mannix]

Tube noise ...or lack thereof?


http://www.john-a-harper.com/tubes201/#Noise

[the_big_m_in_ok]

Hi Lindsay

I for one will keep collecting and building with tubes. Recently bought a batch of several hundred at an auction for $5. Included 5U4's and some 6BQ7's, lots of other power tubes. My collection is in the thousands.

I'm gonna dig up that 885 gas tube and build the Fairbairn oscillator just for old times sake. I found the Fairbairn patent.....1952. Here it is:
(attachment: "pat2607897.pdf")

The attachment wouldn't run on the borrowed computer I was using.  This file would run:

http://www.google.com/patents?id=pD9WAAAAEBAJ&pg=PA1&dq=patent:2607897&as_drrb_ap=q&as_minm_ap=0&as_miny_ap=&as_maxm_ap=0&as_maxy_ap=&as_drrb_is=q&as_minm_is=0&as_miny_is=&as_maxm_is=0&as_maxy_is=&source=gbs_selected_pages&cad=1#v=onepage&q&f=false

--Lee

[Grumpy]

full spectrum noise looks like a dc bias

edit: you can get Vaccum Tubes by Spangenberg here or on a CD via Ebay

http://ken-gilbert.com/techstuff/spang/Spangenberg.html

[darkspeed]

http://www.diyaudio.com/forums/tubes-valves/108768-hybrid-power-supply-diode-bridge-into-diode-tube.html

http://www.freewebs.com/valvewizard/bridge.html


http://www.emissionlabs.com/datasheets/EML5U4G.htm

[Grumpy]

I almost forgot:

full spectrum noise is synonymous with certain forms of radiation and radiation-like phenomena...

hint hint

[BEP]

Does anybody have verifiable information on what the 'B' means in 5U4GB ?

I know there are differences between the 5U4G and 5U4GB. Not enough to worry about when cross referencing for most applications but, the RCA flavor of the 5U4GB may have some less common heater properties. The other differences have proven enough for me to not waste time on a 5U4G.

[poynt99]

The only difference I could see noted in the RCA RC-21 spec book was that the two use different outlines. They only give the specs for the GB version in the book.

.99

[darkspeed]

The 5U4G is a coke bottle tube - the other just a straight tube

5U4GB is lower internal resistance and higher peak current

Up to 5v and 50ma difference depending who made it

In audio terms the 5U4G is tighter than the 5U4GB - once again depending on who made it

[BEP]

The 5U4G is a coke bottle tube - the other just a straight tube

5U4GB is lower internal resistance and higher peak current

Up to 5v and 50ma difference depending who made it

In audio terms the 5U4G is tighter than the 5U4GB - once again depending on who made it

Tighter? As in 'lower head room'? I used to know all those terms but my hearing went South a couple of decades ago.

I guess I'm looking for details not usually supplied. I have mil-spec manuals referring to requirements of thoriated tungsten direct heaters. I've never heard of thoriated tungsten on the heater, just the cathode sheath.

Once upon a time you could tell the heater makeup by the color at rated voltage. Dull to mid-bright red meant thoriated tungsten. Mid-orange to bright orange meant tantalum oxide on tungsten, etc.
I have one RCA with very little use. The heater is a dull red at 5V 3A.

[darkspeed]

Sorry I was vague.. the audio guys have the opinion that the 5U4G is better at enabling a well built tube amp to reproduce high frequency signal.

How they tell that I have no idea.. its all sugar pills to me..

http://www.nj7p.org/Tube4.php?tube=5U4G

http://www.r-type.org/pdfs/5u4g.pdf

http://www.r-type.org/pdfs/5u4gb.pdf