Over the years, I've always used a pair of ceramic wire wound 25W rheostats as load banks. I set the resistance I want to test, then just ramp up the power, and back down. I've connected them together and put 70W into them in parallel with no ill effects, many times.
Lately, I've been repairing increasingly powerful amplifiers, to the point where I have no means of checking full power operation. I looked into load banks, and large power resistors, and have found a few options, but nothing which suits my needs, and desire for a low price point. Basically what I want is something which can take at least 200W per channel, has no heat sink or cooling requirement, and is as cheap as possible. Here's what I arrived at.
20 x 160 ohm 10W ceramic wire-wound resistors in parallel per channel. I'm going to make a plywood base, and put two 14AWG copper bus wires about 3" apart, elevated about 1" off the surface of the wood by wrapping around and soldering to finishing nails every few inches. Then, just solder 20 resistors between them in a line, with about an inch between each resistor. Then, make a second one for the other channel. The total cost of the resistors was about $26CDN at Mouser for both channels, the rest can be made from scraps I have laying around. That's $13 for a mono 200W load bank which requires no external cooling or heat sinking.
I'll post a pic when it's done. I think the first use will be bench testing a Sansui 9090DB properly at full power. Then I have a NAD amp which apparently goes into protection mode too early.. will be great to have the correct tool to figure out why!
Lately, I've been repairing increasingly powerful amplifiers, to the point where I have no means of checking full power operation. I looked into load banks, and large power resistors, and have found a few options, but nothing which suits my needs, and desire for a low price point. Basically what I want is something which can take at least 200W per channel, has no heat sink or cooling requirement, and is as cheap as possible. Here's what I arrived at.
20 x 160 ohm 10W ceramic wire-wound resistors in parallel per channel. I'm going to make a plywood base, and put two 14AWG copper bus wires about 3" apart, elevated about 1" off the surface of the wood by wrapping around and soldering to finishing nails every few inches. Then, just solder 20 resistors between them in a line, with about an inch between each resistor. Then, make a second one for the other channel. The total cost of the resistors was about $26CDN at Mouser for both channels, the rest can be made from scraps I have laying around. That's $13 for a mono 200W load bank which requires no external cooling or heat sinking.
I'll post a pic when it's done. I think the first use will be bench testing a Sansui 9090DB properly at full power. Then I have a NAD amp which apparently goes into protection mode too early.. will be great to have the correct tool to figure out why!