I am wondering how to determine the wattage needed for the 20ohm resistor in this crossover. I'm running 100 watt sensitivity speakers and the amp puts out 10 watts or less.
Also, how important is the inductivity of the resistor. I have some wirewound resistors but they are not non-inductive.
Thanks in advance.
Also, how important is the inductivity of the resistor. I have some wirewound resistors but they are not non-inductive.
Thanks in advance.
XSim software can easily calculate that for you. Since your amplifier power is on the lower side, there is nothing much to worry about.
Depends on the application & how much you're putting through it but for typical systems, especially low-power types 10w rating tends to be acceptable in the HF & cost very little. The inductance of most wire-wound resistors is at best negligable, and many higher-rated types for loudspeakers that are claimed to be non-inductive are not in fact non-inductive at all (my retired industrial electronic engineer father rolls his eyes at most components specifically flogged to the audio market, and with good reason) so I wouldn't get especially worried about that.
Great info. I have some of the aluminum bodied 25 watt (if mounted on a heat sink which these would be mounted on wood) Ohmite non inductive resistors in stock.
Inductance is a non issue at those low resistance values as it is very very low indeed.
Looks like worst case is with the pot at one end and so if we imagine the 4mF (uF) cap were not present (shorted) then the dissipation is just 4 watts assuming your 10 watt figure is based on an 8 ohm load. With the pot at one end the 20 ohm is effectively directly across the amp output. 10 wrms/8 ohm means the amp puts out about 9 volts ac.
In practice and with typical programme material I would think even a 2 watt metal film would not even get warm with that particular amp.
Looks like worst case is with the pot at one end and so if we imagine the 4mF (uF) cap were not present (shorted) then the dissipation is just 4 watts assuming your 10 watt figure is based on an 8 ohm load. With the pot at one end the 20 ohm is effectively directly across the amp output. 10 wrms/8 ohm means the amp puts out about 9 volts ac.
In practice and with typical programme material I would think even a 2 watt metal film would not even get warm with that particular amp.