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Resistor wattage help

Copa1934

Copa1934

My ears are bleeding
More often we see posts regarding capacitors. Usually the recommendation is same or greater "voltage" value, and where voltage is not known usually 50v, or greater, is suggested.

But I have resistors to replace. Not because they are bad, but because the leads are literally broken off at the resistor.

The value is 1-Ohm, 15w. I know to stay with 1-ohm so as not to change the crossover characteristics, but what wattage would be safe? I realize that we're not talking about "RMS" wattage but rather "current".

Is there a minimum wattage that is safe? Is there a rule depending on the amount of wattage, again RMS, that is fed?

Thanks!
 
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Looking on eBay I've come across "Aluminum Case Power" resistors. They have ring like terminals rather than leads. They're also reasonably priced and start around 25W. Are these suitable or meant for different applications.
 
I expect the stock resistor's wattage rating would pretty much define the minimum for an appropriate replacement. One could also go higher of course.

Not all of the aluminium clad power resistors are "non-inductive." Manufacturers offer both types which look identical. But non-inductive units are typically twice the price. Note part numbers and consult data sheets. Non-inductive Vishay/Dale are the NH series, for example. Arcol are NHS.

Except for being pricy, seems to me these have the qualities suitable for crossover duty: high power, tight tolerances, non-inductive ... and they look purdy. What more could you want?
 
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Are you talking about sandcast resistors for speaker crossovers?

10 Watt resistors are pretty much the standard for those.

If you really needed a 15 watt rating a cheap and easy way to do it would be to buy two 2 watt resistors and wire them in parallel. That would give you a 1 Ohm 20 watt resistor. :thmbsp:
 
I have worked on rebuilding PA cabinet crossovers with upwards of 1000w power handling capabilities, and don't recall seeing any resistors higher than 10w. 15w might have just been overkill.
 
Agree on 10W being a good safe minimum, unless it appears that the manufacturer deliberately raised the rating on a particular circuit. Pretty much every pair of speakers I've worked on was 10 at most, stock. The only exception I recall was the JBL 4435 lower bass woofer, which has four ten-watters in parallel for an effective forty-watt (!) rating.
 
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Zonker92 said:
Agree on 10W being a good safe minimum. Pretty much every pair of speakers I've worked on was 10 at most, stock. Only exception was the 4435 deep bass woofer, which has four ten-watters in parallel for an effective forty-watt rating.
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I'm wondering about the math here. You state 40w (4x10), which makes sense to me. Sound states 2x2 for 20w total. Now, I know that caps have very different behavior when wired in parallel vs series, but resistors?

I would suspect that 15w may likely have been what they stocked, overall, and or simply used because of availability or cost. But I just wanted to play it safe.

I rarely feed more than 5-10 watts to my speakers.

I like the idea of the aluminum, assuming the cooling affect would be effective in a speaker. Didn't know, however, about the non-inductive vs inductive, so I'll have to pay attention to this when I order the resistors.

I'll wait for any additional posts, comments before buying. Not in a hurry and hope this post will help others who have to replace resistors for similar reason.

I've never had to replace resistors before. All have checked out, in most cases near perfect. So saw no reason to replace. But with broken leads that changes things.

Appreciate all the input.
 
Small Caveat:
Take Extreme Care in buying Electronics bits on Ebay.
Fakes are pretty well ubiquitous.. Even 1 cent resistors, let alone more expensive ones
 
bare said:
Small Caveat:
Take Extreme Care in buying Electronics bits on Ebay.
Fakes are pretty well ubiquitous.. Even 1 cent resistors, let alone more expensive ones
Click to expand...
Definitely NOT going for the cheapest. I look at feedback too to make sure. The more positive feedback the better. Also look at whether or not the normally sell electronics or just "dumping" stuff they have. And last, if what's for sale is NOT the image I pass.

Thanks for the warning.
 
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