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Is there any difference if a tube is mounted verticaly or
horizontaly? Will They sound different? Will they last just as
long?
Just curious.......DK
Follow Ups:
that preamp tubes mounted horizontally have less shot noise, but I haven't seen that mentioned elsewhere.
Specifically the RGN 2504 mesh plate rectifier. Heard from Tim(Hong Kong Tube Club) that he removed while still hot and laid it on its side. Result: FRIED!!
or upside down and see what happens :)
Dave
...for every rule there are notable exceptions.
Thats true but the RCA spec sheet states they should only be mounted vertically socket down but they seem to do ok in Hickok testers like you say :)Dave
if there is any question, check a tube manual. They will generally state whether a tube can be used in any orientation or if it needs to be vertical. Some tubes can be horizontal only if they are aligned in a specific way. As Steve O states, that is because of potential sagging of a hot filament. As a general rule DHTs need to be mounted vertically whereas indirect heated tubes (IHDT), where the cathode is separate from the heater, can be mounted in any orientation. Some rectifier tubes can be mounted horizontally but only if the tube pins are in a certain orientation, again due to the way a heater filament could sag.
Thanks all for your posts!You brought up conciderations I
would never have thought of.....THANK YOU !!!!!......DK
Tubes with cathodes are not as picky. Directly heated tubes (5U4, 2A3, etc.)are another story. If mounted horizontally, the filamentscan sag and short out to the grid or plate.Hope this helps! Al
See a tube reference manual, like the venerable RCA Receiving Tube Handbook. Many tubes are only recommended for vertical orientation, and others can be mounted horizontally, but often only if certain pins are in the horizontal plane. I think the Earth's magnetic field comes in to play.
"I think the Earth's magnetic field comes in to play."Actually, it's earth's gravitational field that comes into play. If you examine carefully the permitted horizontal orientations, you'll usually find that it places the plane formed by filament structure in a vertical position. IOW, the inevitable filament sag will occur in a direction were clearances betw it and other electrodes are greatest.
Note that in almost all cases of receiving tubes, the orientation restrictions apply to directly heated cathodes only: IDH are usually without restriction.
AudioSoul,There is so much tube gear with horizontal tubes- going back a long while- I'm thinking of 40's communication gear, the famed REL Precedent tuner of 1954 and the Audio Research D250 of 1984 with it's 16- horizontal 6550's. I have to think there are no serious penalties. The structure of the tubes too with plates spanning between micas keeps everything in proper realtionship and are of course made to be shock resistant- tube car radios, WWII walky-talkies, the first portable radios.
And since tubes' electrical operation is not affected by the orientation,- electrons moving 1/8" in a vacuum won't notice gravity- so I don't think there's a sonic difference. There could of course, be a sonic penalty if the mounting was loose and allowed the tubes to "sag" enough to affect socket/pin contact.
I don't know fully the reasons for horizontal tubes- it would save height, but the D250 could probably have had it's 16 output tubes vertically on the same footprint chassis. There is something attractive whne looking at the D250 from above and seeing all the way through the centre volume where the output tubes are- I visualise much better air circulation than if there was a solid chassis under. Still, I also visualise the heat from the lower rows of tubes rising and adding heat to the tubes above -a 6550 convection cooker, with the upper tubes hotter than the lower.
Probably the clamping action of the sockets on the pins, and in the case of power tubes the centre guide pin having some length- creates a tiny cantilever. I have always felt a bit nervous about it, but history seems to accept the idea of tubes laying down on the job.
Still, there hads to be agreater chance of a horizontal tube loosening if the gear is shaken. I would probably be extra careful when ever moving gear with horizontal tubes to either take the tubes out or if it's only across the house- check the seating of every tube- twice- after moving it.
Cheers,
Bambi B
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