I am working on a dummy load as well and was trying to mostly use parts that I already have. My plan is to house this in a Hammond 1590D aluminum enclosure (7.4x4.7x2 inches),and use 2 8 Ohm 100W resistors, 3 TRS jacks, and a 3PDT switch. My 3PDT is rated: 250vac at 3A and 125vac at 6A. Hoping that the enclosure will provide enough of a heat sink for the 2 resistors.
Schematic attached. The switch in the "up" position on the schematic will be for a 4 Ohm load at 200W. The 8 Ohm jack should work regardless of switch position at 100W and the 16 Ohm jack would work with the switch in the down position at 100W.
I am wiring the + side to the Tip and then the - side wired to the Ring. Ground is wired to the Sleeve. That way when a mono cable is inserted there is a connection made between the Ring and Sleeve to provide a ground for the circuit.
I would use this when testing amps or burning them, so I don't want a reactive load.
Does this look like it should work? I am not sure what kind of current the 3PDT will see.
Thanks
-Dan
Good designs for dummy loads?
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Re: Good designs for dummy loads?
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Re: Good designs for dummy loads?
I've taken to using an dryer heating element, clip on to the needed resistance, simple stupid. Rated to 5k. I know there's bones to pick with it, but heck,... free to cheap.
lazymaryamps
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Re: Good designs for dummy loads?
Absolutely this....
https://www.thegearpage.net/board/index ... d.1072793/
i built one....sounds terrific! FEELS terrific.....very cheap to do too....
don't do resistive load....do a reactive load....
here is my build....thats a computer fan on the heat sink...now the case does not get hot.
https://www.thegearpage.net/board/index ... d.1072793/
i built one....sounds terrific! FEELS terrific.....very cheap to do too....
don't do resistive load....do a reactive load....
here is my build....thats a computer fan on the heat sink...now the case does not get hot.
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Re: Good designs for dummy loads?
Take the resistors you need, - usually 10 or 20 ohm ww's will do, and dunk them in a quart paint can with oil... add connectors, switches - whatever..... if you need sustained loading, - use a gallon can.... This has been used for RF for ages....
Re: Good designs for dummy loads?
you mean 10 or 20 Watt, right?
Tube junkie that aspires to become a tri-state bidirectional buss driver.