Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: TexasRugger on May 19, 2010, 01:55:19 AM
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Time for my next noob question - I fired the amp up last night after testing (sounded fantastic) and noticed that the top plate gets very warm. Almost hot. Is this normal? Anything I should be concerned about? Thanks,
Tex
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That's normal.
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I realize that this isn't a very "green" thing to say, but I ran my Crack 24/7 for about a week (burning it and another piece of gear in) and it had absolutely no problems. The top plate does border on getting hot or at least what I'd call, very warm.
Just be sure and install the included feet on the bottom to get some air flow. In fact, since I'm a little paranoid about gear getting too hot, I've since put a set of slightly larger feet (about 2/3" as opposed to the 1/4" supplied) and it seems to help a lot.
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If you do a search about transformers and heat you will find that the engineer who designed the current transformers, Paul Joppa, designed them to run warm. The insulation in the transformers is rated for the heat and they never get so hot as to be dangerous.
The real key, or the best part, is that the transformers are shielded and radiate less than stock or the general transformers on the market. That is the reason why Paul Joppa designs his own.
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The heat is normal, the two 3K, 10W resistors each dissipate about 3.5 watts, so there is a 7 watt heat source just below the chassis plate. The vent holes do help, but as stated earlier, they won't work unless the rubber feet are used to raise the wood base, which will then allow for convective airflow.. The two 270 ohm resistors in the PSU also dissipate a 1.73 Watts each. So there is a total of almost 9 5 watts of resistance "heaters" under the chassis plate.
I found that the tranny and the tubes run at relatively mild temperatures, the 6080 is loafing along at about 5W total plate dissipation, plus about 16W of filament consumption.
HTH
/ed B in NC
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If you think the Crack runs hot, try Paramounts!
I can't agree more with the comments about the necessity of the rubber feet. You guys really hit the nail on the head. In adding the vents, I wanted some airflow without making the chassis plate weak, and that is part of the balance in the size and shape of the holes. It is also good if small fingers, paws, and claws can't reach in and touch live terminals. Unfortunately, the vents are not paperclip proof, but it's still much safer than a toaster!
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Ok, thanks for the responses and help