5840 tube question

[Oddvar]

Might be the wrong place this, but I wonder if anyone could tell how to turn a 5840 tube into a triad, I need to know how the eight pins can be connected to: anode, H+, H-, gate and cathode?  Eight pins into five points. I have looked everywhere, but info is a bit vague.  Best advice so far is in the pic, but I am in the dark.  Some say one shouldn't kee pins unconnected, if so, who should go where?

[sluckey]

This tube has wire leads instead of pins. It does not plug into a tube socket.



Lead 1 connects to the grid circuit.

Lead 2 connects to the cathode circuit. Just tape off leads 4 and 8 since they are internally connected to lead 2.

Connect leads 5 and 7 together. This makes the tube a triode. Connect the two leads to the plate circuit.

Connect leads 3 and 6 to the 6.3V filament supply.

[Oddvar]

Great Sluckey, thank you ever so much.

[DummyLoad]

This tube has wire leads instead of pins. It does not plug into a tube socket.

But can and do have sockets specifically for them.

https://www.dropbox.com/sh/u690mpdw8qxiqid/AAAPv8EpvgAJnfk5NznxyMbza?dl=0

They (sockets) are scarce and are a pain to solder to - Typically I use 24-26AWG solid core teflon insulated wire. Those pics are of a pedal I was working on. Two 6788 pentodes and a 6948 dual hi-mu triode. Power is provided by a wall-wart to a 5W DC-DC converter supplying ~200VDC for the B+ rail. Wall wart provides 15VDC@3A and we regulate 6VDC for filaments with a 7806 linear v. reg.   

--Pete
 

[kagliostro]

On e-bay you can find this to simplify your life

https://www.ebay.com.my/itm/201105035628








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Also this is an option but, can I say, expensive


https://www.ebay.it/itm/175204203602?chn=ps&norover=1&mkevt=1&mkrid=724-128315-5854-1&mkcid=2&mkscid=101&itemid=175204203602&targetid=1827389197184&device=c&mktype=pla&googleloc=1008894&poi=&campaignid=17955385566&mkgroupid=142692416071&rlsatarget=pla-1827389197184&abcId=9301109&merchantid=116379287&gclid=CjwKCAiAy_CcBhBeEiwAcoMRHLZYQw9-CKZkK2i8XtmnvtpxQVrbllDn7dlnroplu5-S0Xp6Ubp6xhoC7hcQAvD_BwE




Franco

[scstill]

Connect leads 5 and 7 together. This makes the tube a triode. Connect the two leads to the plate circuit.

perfect timing for me as I am triode strapping a #78 pentode and 6A7 pentagrid (still have two grids on this one to deal with)

I have read that if you add a 100R between screen and plate it works better because it prevents parasitic oscillations, whatever that is :-)  http://www.audiodesignguide.com/New2A3/ETF06TS.pdf

also, Can we use the same pentode curves for setting bias when operating as triode?