resistor size to safely dissipate current

Hi, I saw an amplifier tech on Youtube show how to dissipate current from the rectifier (on a tube amplifier) to ground while he worked on a section that was close in proximity to the diode rectifier section. He called for a 40K 20 watt resistor to be used. I can't find one that big but I do have a 10K 50 watt resistor. Would that work? What thought process would you use to know how small you can go. I believe his amp had no pwr xfrmr so the voltage on the rectifier would have been 115V x 1.4 (as far as I can assume).

by murfbass
February 02, 2019
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1 Answer

Answer by getwood

If you simply want to replicate his rig, two 20K 10-watt wirewounds (at under $6.00 CDN each) will work; in fact, separating them like this would have some advantages, chief amongst them better heat dissipation.

See, for example, this:

https://www.digikey.ca/product-detail/en/riedon/UAL10-20KF8/696-1428-ND/3886629

+1 vote
by getwood
February 04, 2019
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