just wanted to ask if this load resistor is appropriate for bench testing the amp out of the leslie, or can someone suggest a better alternative. thanks.
It's overkill for your needs, but it would work. I use a couple of smaller chassis-mount resistors mounted to an aluminum heatsink, and I can configure them for 4, 8, or 16 Ohm loads.
thanks David, i wish i know how to build something like your set up and what those parts would be. your response makes me feel comfortable to use what's in the picture
You can look up 'speaker dummy load' online and get some pointers. Many people use the gold-colored chassis mount wirewound resistors, but these do have to be mounted on an adequate heatsink (as listed on datasheets) with thermal grease to get maximum ratings.
If you use two 8Ω resistors, you can put them in series for 16Ω and in parallel for 4Ω.
My late brother used to use a huge power resistor to test solid-state amps he repaired for dance clubs, and he would put them in a bucket of water for cooling. No joke.
=-O bucket of water!!! OMG that's hilarious
let's say i would go your recommended route with two 8 ohm resistors mounted on a heatsink...what wattage those resistors should be? are these resistors need to be non inductive? i might stop by an electronics store not far from where i work. thanks again
The wattage of the resistors would depend on what you plan to test. If you go with two 8 Ohm 50W resistors with adequate heatsink area, you can test amps up to 100W @ 16 and 4 Ohms and up to 50W @ 8 Ohms.
My brother was testing amps that put out ~1,200 Watts, so he had two large, hollow resistors, screwed together at one end, with the other ends coming up out of the water. I'm sure there are more professional ways to do it, but it worked.
Yes, that should work, as long as the heat sink has the surface area required. That information is on the resistor datasheet. And mount the resistor with thermal grease under it for better thermal transfer.
the local electronics supply store i mentioned didn't have any of the two items, so i went and purchased the ones on e bay. thanks so much for the help David, i really appreciate it.
I have a 147 amp. Never knew the reason for the impedance selector switch and if using the amp with a clone through a preamp pedal, where should the switch position be?
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