heat_articleThe appearance of amplifiers hasn’t changed much over the years, which is why a warranty return made to hi fi salesman Geoff Barrett was so arresting. “It looked like something designed by Salvador Dali,” he said.

Barrett is a veteran of hi fi retailing and in all his days he has never, before or since, seen such damage done by overheating. It all started in the early 1990s when one hi fi brand that was obviously paying more attention to its stylists than its engineers started encasing its products in plastic, rather than much less pliable steel.

This made for amplifiers that looked fantastic, with cutting edge designs that spoke of high tech, sophistication and elegance. Adding to their aesthetic appeal was a complete lack of vents. When Barrett saw the first one he predicted disaster – where was all the heat going to go? – but his store manager went ahead and stocked them anyway.

The thing about amplifiers is that they are almost always the biggest of all the various components in a hi fi system, and that means they’re almost always at the bottom of the equipment stack where ventilation is usually worst. So when these units were operating the heat build up was fast and the heat dissipation was slow.

Barrett recalled that every one they sold was returned on a warranty claim. Every one. The cabinets got so hot they distorted and in some cases began to melt, and the Salvador Dali amp was born.

“Our complaints to the manufacturer were brushed off as user mishandling,” he said. “Eventually they supplied us with plastic brackets so the amplifier could be placed at the top of the stack but it did nothing to fix the problem. Needless to say the hi fi store I worked for returned all remaining stock and severed our connection with the brand.” And the brand has never recovered.

Barrett, now retired, remains a hi fi enthusiast and thinks the stylists may be getting on top again as profit margins triumph over sensible designs. Corporate amnesia has set in, he believes, and he wrote to us recently bemoaning the reducing lack of importance component manufacturers seem to be paying to proper ventilation.

“Over the last decade I’ve bought a number of electronic components and I’ve been horrified at the minimal or absent allowance for getting rid of the heat, the only exception being computer towers. It may be counter intuitive, but digital components generate more rather than less heat than analogue, and when digital components overheat they just stop,” he said.

“I have recently purchased a couple of components that are housed in sealed metal cabinets with no ventilation slots and feet that give barely two millimetres of clearance. Both devices give excellent results until they’re heat stressed by lengthly use or high ambient temperatures, then one simply closes down and the other does things that the product hotline people told me are impossible. I’ve remedied the problem by using spacers to give them five centimetres of clearance on all sides.”

He said using spacers to separate components in a stack is a must and he doesn’t hide his equipment away in cabinets. But with the current trend towards minimalism and keeping components out of sight lots of people do. “Unless precautions are taken I predict nothing but grief and frustration and, in the worst case, the danger of fire,” he said.

The veteran editor of Australian Hi Fi magazine, Greg Borrowman, agrees. “A lot of these things are disasters waiting to happen,” he said. “Little attention is being paid to the problem of overheating and it’s only getting worse. We’ve seen one that closes down when the internal temperature reaches 38 degrees. In an Australian summer that’s not a terribly useful piece of equipment.”

He said that many cheap components coming out of China were particularly worrying.

“Their manufacturers copy brand-name products with no real understanding of the engineering,” he said. “They see a big, heavy heat sink and they immediately reduce the size and weight to save money. They use cheap, even fake internal components to save cost and send them out the door.

“And then they’re brought here by an importer who disappears after they’re sold simply by changing his post office box number.”

The fact that manufacturers and importers can now carry out their own CE certification, declaring components safe for sale in the European Union, is making things less safe here in Australia Borrowman says.

“Australian authorities accept CE certification as proof that a product is electrically safe, so an importer only has to declare that the product has a CE certificate for it to be approved for sale in Australia. There are no local tests carried out at all,” he said. “It’s only when things start going wrong that independent checking is carried out, by which time the importer may have changed post office box numbers.”

So what can you do?

Firstly make sure your equipment is well ventilated, with plenty of space around all sides and top and bottom for air to circulate. Three centimetres is good, five is generous. Secondly monitor your equipment, especially when it’s new. It’s as simple as reaching in and placing your fingers on the cabinet top and sides. All equipment gets warm but it shouldn’t get hot.

Finally, remember that you get what you pay for.

Published August 2012