metal shield

[dud_wity]

hello
im building a guitar head amp and my 2 x rca12ax7 are under the chassis. i have a metal shield cup that can be pot on both tubes with metal spikes inside that touches the tube glass.

the metal will keep the tubes cooler? should i pot the metal shield cups or leave the tube naked?
under the chassis there isn't much breeze for it to cool...

what are you suggesting?

have a great day
David.

[Sch3mat1c]

A 12AX7 isn't going to care about heat. This style will not cool to my knowledge.

Tim

[benny]

if your tubes are inside the chassis, it is not keeping the tubes themselves cool, but the entire chassis you should worry about.... tubes will always be hot, you can't change this, and this is why when you mount them inside the chassis, you must keep it well ventilated, even install a small fan to ventilate it... heat is one of your electrical components worst enemies.

if you want to use the sheilds as some sort of heat sink, then you will want to keep the conduction path going all the way to the chassis, or some larger external heatsink, because the heat will need to escape somewhere, so sheild or not, your chassis will get just as hot unless you can conduct the heat to outside.

cheers

[dud_wity]

i will make some changes in the layout to allow the heat to escape.
have a great day!

David