How hot should chassis plate get?

[denti alligator]

I wondered this for the first time today. Mine isn't too hot to touch, but it's pretty damn warm. Is this normal? I'm worried the wiring inside might get too hot and cause trouble down the road. Should I relax?

[groomster]

I had wondered the same thing for days after noticing that the top plate  was hot and the tubes were extremely hot, but was assured this was normal.  I'm almost assuming that if it does not get hot, then something must be wrong!!  Anyways, I am not an expert on it, but just thought I would throw my 2 cents in.

[InfernoSTi]

Here is a similar question and answer (in short, it is normal).

http://www.bottlehead.com/smf/index.php/topic,739.0.html

If you are used to transistor amps, tube amps will seem very hot.  This was one of the reasons "they" said transistors were "better" than tubes back in the day. The resistors have a lot of heat to shed due to the higher voltages the tubes use so it is a combination of sources of heat.   Just make sure you have good air flow by using the little feet under the wood case so that air can circulate.

Oh, one more thing: just because you can fry an egg on it doesn't mean you should....

John

[Grainger49]

It may be more of a class A amplification thing than just Thermionic thing.  Class A transistor amplifiers stay pretty hot.  The heat is a reason Bottlehead has warned against using the Bees wax caps under the hood in the SEX amp. 

In addition, PJ has designed the power transformer to run hotter than many people are used to.  He includes winding techniques and shielding that keeps the circuit quiet.  He includes insulation for the windings that is safe running at the temperature that the transformer reaches in normal use.

Both are normal things and shouldn't burn you.  You won't want to leave you hand on either the top plate or transformer bell for a long time, but It shouldn't hurt you.

[Jim R.]

I suppose that if you were careful, you could drill a matrix of small vent holes above where the cathode resistor is and that would allow for more air flow across those, which are probably the hottest parts under the hood, except maybe the resistor in the heater supply or the transistors in the c4s boards.  I didn't do this with mine though I did think about it.

-- Jim