[tx2sturgis]

I was very surprised to note the glass surface temperatures with, and without, the tube cage. Nearly 200 degrees hotter measured in about the same place, with the tube cage in place for an hour or so.

Wow.

[FullRangeMan]

How so 200º hotter? You must be talking F deg.

[bregez]

Yeah its not an absolute lab measurement in any case....just for reference, the IR gun that I used measures the glass surface IR...it has no way to see the plate

This image shows how there is a temperature gradient on the glass of a tube.  The signal tubes (12AU7) run cool on this line stage (Hagtech Clarinet). Image was taken with a SC-6000



I like to use passive thermography after a build as a check to make sure components are not stressed.  This image shows the power supply resistor getting hotter than the other components.  It also shows the temperature of the board under the tubes





 

[tx2sturgis]

How so 200º hotter? You must be talking F deg.

Yep...that celsius stuff is a passing fad....