HT 100 head really hot

[Buzzzsaw]

I just bought a used HT-100 head to replace my HT-60 Stage combo.
The head plays really great, the sound I get out of it is even better than my old HT-60.

The thing is: the amp gets really hot after some use.
I had a band rehearsal yesterday that lasted 2h30, and when I went to turn the amp off, the metal plate on top of the lamps was burning hot (I left my hand 3 seconds on it and I almost got a burn). The wood was hot too, but not that much more than the HT-60 in similar context.
I checked the lamps right before turning the amp off, and they had a nice orange-ish color with a blue glow, and the plates weren't colored.

Is that amp supposed to run this hot?
Is mine biased to run too hot?
Am I worrying for nothing?

Thanks!

[thephantum]

First of all, biasing has nothing to do with how much or little heat an amp will produce. When someone talks about biasing an amp cold, warm or hot, they are referring to current level, which is based percentage of maximum plate dissipation used in the calculation. So for example: 60% of max plate dissipation is considered cool, 70% is warm and 80% is hot. Again, it has nothing to do with how hot the amp will get.

Also, looking at the tubes will tell you nothing about them. The only exception to that is if they are red plating, which is a very specific kind of failure.

Tube amps get hot. I've had heads with no issues....but I swear I could have fried eggs on them they got so hot. Keep in mind that the HT-100 has four EL34's where the HT-60 only has two. So it's generating twice the amount of heat. I don't think it's anything to worry about. However, I would have the amp re-tubed and checked out by a tech. Not because it's running hot, but simply because it's used.

[Buzzzsaw]

Thanks for the feedback, thephantum!

I understand what you say about tube biasing. I'm still kind of new to this!
So in the end, I understand that there's nothing to worry about, as long as there's no smoke coming from the amp!

Even though the previous owner told me he got the tubes checked, I was already tempted to swap the tubes to put some JJ EL34 in the amp, and keep the current ones as backup.

[thephantum]

One piece of advice. Do not move the head when it's that hot. Do so can cause damage to the tubes over time. After a gig, turn it off and give it at least 15 minutes to cool before moving it...longer if possible.

[Buzzzsaw]

One piece of advice. Do not move the head when it's that hot. Do so can cause damage to the tubes over time. After a gig, turn it off and give it at least 15 minutes to cool before moving it...longer if possible.

I'll take note of that.
Thanks for the advice!