I finally got my speaker rebuild together; 15" Eminence Kappa 100db/W and a PSD2002 105db/W. I was warned that I might need to put an L-pad on the compression driver an it turns out the the HF is about 6db bright. So I'm going to make an L-pad using aluminium cased 100w resistors (possibly over kill but.... ). Should they mounted to a heat-sink?
Without the heat sink the resistors would roughly take only about 10% of their rated power.
However, with your speakers you probably won't need the heat sinks.
Fuse the input if you like, a 1A fast blow fuse should be ok.
However, with your speakers you probably won't need the heat sinks.
Fuse the input if you like, a 1A fast blow fuse should be ok.
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I’d use a set of resistors that blow before the tweeter as a way to protect it further. You don’t want the most expensive component to be at risk. If I recall you bought a Eminence 1,8kHz HPF too? Didn’t that include some damping and bulbs bot of which should attenuate about 5dB. Did I you measure the 6dB difference or is it just a theoretical estimate? And did you put a crossover at the kappa? I would suggest a variable LPAD in you case.
Normal 10W wirewound cement resistors will probably be fine for this. @105dB on a 6dB pad they can't possibly consume more than a watt or 2 each and that's pretty loud.
20W cement if you're feeling spendy.
20W cement if you're feeling spendy.
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500W 😕
I did a study on my 108dB tweeters (crossed below 1k), before I built the amp for them. I figured I didn't need much more than 50mW, so I built them a half Watt amp.
I did a study on my 108dB tweeters (crossed below 1k), before I built the amp for them. I figured I didn't need much more than 50mW, so I built them a half Watt amp.
Its in the Original post. A 15" kappa and a PSD2002. Kappas can handle 450watts RMS so its silly not to build the rest of the system to that level. This is sound reinforcement equipment.
The lpad should be put after the high pass filter meaning it will never be introduced to more power than what’s left above 1,8kHz given the full system is 500. I’d say it’s unlikely it will be ever more than 50 watt to the HF. At that point the bulbs in the high pass will start to blink and shortly burn up.
pxb:1K8 can handle 400 watt while the two bulbs will protect the tweeter from anything above 50 watt, which is also where you will put the LPAD. You just need to decide what should be the weakest component of your design. I suggest the bulbs or the serial resistor as the cheapest parts. The bulbs are 25w each (50 watt total). PSD2002 is 80 watt. So your resistors should be somewhere between or lower. Not higher than 80 watt.
pxb:1K8 can handle 400 watt while the two bulbs will protect the tweeter from anything above 50 watt, which is also where you will put the LPAD. You just need to decide what should be the weakest component of your design. I suggest the bulbs or the serial resistor as the cheapest parts. The bulbs are 25w each (50 watt total). PSD2002 is 80 watt. So your resistors should be somewhere between or lower. Not higher than 80 watt.
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Metal oxide resistors do not blow when overpowered, they just start to smoke, glow red, then orange and maybe start a fire in the process. I do not know how wirewound resistors behave.