Aaron's Valve Appreciation Thread

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This thread is about the discussion of thermionic vales or tubes, the application of valves, applicable circuit designs, pictures and diagrams, and anything tube related. doesn't matter of what type; may they be Triode, Pentode, Tetrode, Nixie, Indicator, Rectifier, Voltage Regular, anything that has a glass envelope that is used for whatever post that stuff here!! !

300B a power triode is used in primarily Hi-Fi applications and has a directly heated cathode, It is a REALY old school valve, and is used more-so for nostalgia than actual output power. However it is the most reputed to give any system the sought-after "tube sound" due to its non-liniartity and design. Generally used in SET (Single-Ended Triode) systems.

A glowy picture of a 0A3 Voltage Regulator.

I appreciate my heart valves. Thanks for keeping me alive, fellas. Sorry about all the crap that's probably clogging you up due to my unhealthy eating habits. You're handling it like pros.

Great thread idea! I could fill this thing, but here are just a few of my treasures. Click the thumbnails for larger pictures.

Here is an old picture of a small piece of my tube collection. I have everything from worthless TV tubes to valuable pieces of electronics history from as early as 1915. This case contains my examples of the latter, although there are a few other ones mixed in just because I find them interesting. There is also a ca. 1905 carbon sign lamp in there. I have a few more of those now.

Interesting tidbit, the second tube from bottom right is a Western Electric 101A repeater tube from 1915, the first tube to use the eventually standard UV base. This tube had a useful life of only 400 hours, but still played an important role in the world's first transatlantic telephone system. Mine is an experimental version, and despite being significantly damaged inside, is still quite valuable to collectors.



And here is a headphone amplifier that I built a few years ago. I am listening to it now, actually. It is an OTL design using a 6922/6DJ8 driving a 6080/6AS7. There is a 60-second thermal relay to switch on the HT since this amplifier uses a solid-state power supply, and the 6080 is prone to cathode stripping if not allowed to warm up first.



And here is a ca. 1923-24 homemade (by the original owner, then later by me) TRF neutrodyne receiver that I re-built using the original parts. It was a dirty rust bucket when I found it, and the wiring was completely trashed. Therefore, the circuit and wire routing is my own design, but the placement of parts is original. I simply transferred everything onto a new base board as the old one looked like it had sat in a barn for most of the 20th century. More information about it can be found here: http://theradioboard.com/radiocontest/2 ... windom.htm



These are some fantasy tubes that I drew up in AutoCAD years ago.

Screen Grid Tetrode: Triode (Inverted Construction): Diode (Inverted Construction):

I remember reading a sci fi story as a kid where a guy crashes his space ship on the moon on his way to a moon-base. He goes outside and builds a transmitter, using pieces of metal to form vacuum tubes since he didn't need to create a vacuum.

Love the bus work on the rebuild, point-to-point FTW!

Why a 60 second thermal relay for HT though, wont the cathode reach operational temp in just 20some seconds or less, seems a bit long tis all. : p

Edit: Or why not just use a valve rectifier instead of I'm guessing 1N4007's? A GZ34 could eliminate most of the need for a timer relay, because it's heat cycle would be more or less synchronous with your signal tube heaters/cathodes thus preventing the full HT from being dropped on a cold cathode.

Aw, and here I thought I'd get to share my knowledge of the wonderful world of control valves and Cv, Kc, and "Kahsee" values.

Whats stopping you?

The timing is mostly a matter of convenience, as the 60-second relay was what I could get my hands on. You could just as easily drop in any other one with a 115V heater, and I will put in a shorter relay if I run across one.

I forget the actual specs on the rectifier but it is one of the big bridges rated close to 1KV at several amps that you bolt to the chassis. Again, I had a bunch in my junk collection so I used one, even if it is overkill. The schematic that I based this project on also used a solid-state bridge in the 150V power supply, so rather than re-engineer the whole thing around a tube rectifier, I decided to try it their way.

If I ever built another one (which I have considered because I like it very much) I might play around with a tube rectifier then.

what do people on this thread think of bob carver's "transfer function" meant to emulate the sound of an SET in a powerful transistor power amp?

Blasty, about how much output power are you drawing from the 6AS7?

Maximum output into 600Ω headphones is 170mW; 40mW for 32Ω phones. It runs my 32Ω set with no effort at all, but I would like to eventually get a good set of 600Ω phones to compare.

My amplifier is based closely on one originally designed by Aren Van Waarde, which seems to have become fairly popular.

Just wondering, do you know of any single output trannys capable of handling 500+W output? that are still in production?