Home Propeller Head Plaza

Technical and scientific discussion of amps, cables and other topics.

Re: The 100 ohms resistor...

Just to make it perfectly clear: You can use a somewhat higher series resistor in series with the input stage of a power amp, because it operates at a much higher voltage level than a preamp phono stage, or microphone input stage. A 1 Kohm feedback resistor to ground for a PA amp should be OK. Then the main feedback resistor would be 28.2K for a normal home theater power amp, and maybe more or less for some other amplifiers. If you use +/- 100 Volt supplies and presume a full square wave as a worst case output, then the main feedback resistor must have a rating of 100 squared =10000 divided by 28.2K. This is less than 1W, but it is always best to use the largest resistor that is practical in order to keep changes in temperature of the resistor to modulate the output voltage. Still, a 1W resistor can be compact enough to be board mounted and not require an external heatsink. Even a 1/2W resistor (what we use) is good enough with a good resistor and normal operation.


This post is made possible by the generous support of people like you and our sponsors:
  McShane Design  


Follow Ups Full Thread
Follow Ups
  • Re: The 100 ohms resistor... - john curl 00:52:14 08/23/06 (0)


You can not post to an archived thread.