Vertical vs. Horizontal – does it matter?

[Joshua_G]

Are there any implications or considerations for mounting tubes vertically or horizontally?

Are there difference between small signal triodes, power pentodes and HT rectifiers?

 

[jmilch]

Are there any implications or considerations for mounting tubes vertically or horizontally?

Are there difference between small signal triodes, power pentodes and HT rectifiers?

The original datasheet will tell you what mounting limitations a particular tube may have.

 

[Joshua_G]

The original datasheet will tell you what mounting limitations a particular tube may have.

Thanks.
1. Most data sheets don't mention this issue.
2. Even for tubes that the data sheet says they can be mounted either way, there may be some issues related to mounting position, like sound quality, immunity to vibrations and lifetime.
Therefore my questions.

 

[kavermei]

If you want to mount tubes horizontally, it is usually best to make sure that the posts which support the grid wires are in the same vertical plane. Otherwise the grid wires may sag because of the heat, and at one side will come closer to the cathode while on the other side coming closer to the anode. That would change the characteristics of the tube.

 

[analog_sa]

Yes, DHTs can even fail if mounted horisontally at the wrong angle.

 

[Joshua_G]

Thanks.
What's DHTs and which angles are wrong?

 

[analog_sa]

I'll leave to someone else to explain what's DHTs If the filaments are not perpendicular to ground they may eventually sag and hit the grid.

 

[Sch3mat1c]

Directly heated rectifiers also recommend this, e.g. 5Y3, 5U4, etc. I suppose the grid is closer to the filament in a triode than a rectifier, making this an even greater concern.

Tim

 

[pointy]

the internal heating will be different due to thermal lift. also some of the external wires may sag and short in horizontal mode.

 

[Sch3mat1c]

Well, the envelope will be hotter on the top side unless you use a fan (and if you have a lot of tubes crammed inside, that's a good idea, as Tektronix did back in the day). In a vacuum, heat knows no gravity.

Tim