For years I've been using plain old resistors for amplifier loads but the largest I had was rated at 100W and they became hot very quickly. Some Google searches turned up a suggestion to use heating elements as loads. A bit of searching on Amazon turned up some Emerson/Maytag dryer heating elements. They are rated for 4750W each, no issues with capacity and just over $20 each delivered, so worth a shot. One thing that was an unexpected bonus, the coils are wound in opposing directions for each row, making the load essentially non-inductive. The LCR bridge shows only about a 20mOhm difference between 100Hz and 10kHz, close enough.
The overall resistance is about 10.6R, so I simply measured from each end to find the 4R point, cut the coils at that spot and tied them together along with some 10GA wire. This allows for 8, 4 and 2 Ohm loads with various jumper connections. I finally got around to mounting them in something non flammable and with plenty of airflow. I purchased the chassis from JoshK many years ago and we used it at work for a drive array until recently. It was going to the trash and it occurred to me that it would make a dandy housing for this purpose. All the other components except for the fan and banana jacks were scrap bits; much to the agony of my wife, I am a pack rat. The front plate was some leftover 2U rack mount panel, the brackets one the wire end of the loads were from a failed transformer, the other brackets from a dead amp, they originally held some heat sinks. Some aluminum angle for the panel mount, no idea where it came from but it was a freebie, some extra holes but they don't matter.
Not pretty, very industrial but works well. The fan is rated at 195CFM and even with 1200W into 2R I didn't have any heat problems.
The best part is I have less than $100 invested, excluding the original cost of the chassis and that has long since been recouped.
mike
