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One of four (4) 750 ohm 5w ceramic resistors in a subwoofer's power amp section seems to be open. I want to replace it with a compatible ceramic resistor.

Questions:

  1. Will the 10W one generate more heat?

  2. Is it OK to mix one 10W resistor with three (existing) 5W resistors? (All 750 ohms and 5% tolerance.)

[They are in the immediate proximity of transistors]

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Added on 2/2/17:

I think I was overlooking the importance of derating factors operating temperature range differences when resistors are used in audio amplifiers because audio amplifiers can get hot.

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    \$\begingroup\$ Will the 10W one generate more heat? Nope, it means that the maximum power which that resistor can dissipate is 10 W. \$\endgroup\$ Commented Jan 26, 2017 at 21:43
  • \$\begingroup\$ There are 2 more points which, although not in the questions you asked, might be relevant: (a) There might be an underlying reason elsewhere which caused that resistor to be open circuit. If so, replacing the resistor only fixes the symptom, not the cause, meaning further failures may be possible. (b) A 10W resistor will likely be larger than the 5W original resistor - e.g. one manufacturer shows their 5W resistors are 26 mm long x 7 mm dia and their 10W resistors are 47 mm long x 10 mm dia. Whether the increased size is a problem for you or not, depends on available space etc. \$\endgroup\$
    – SamGibson
    Commented Jan 26, 2017 at 23:52

2 Answers 2

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  1. No more or less heat as total energy, but the 5W unit very likely runs hotter because its cooling is designed to be less effective due the smaller rating

  2. No problems in circuit's function because Ohm's law is the same. Mechanical problems can occur. I've seen, how heavier parts make mechanical resonance frequencies lower and their sheer mass is more tiring to the solder joints. If not mounted with glue or a proper clamp, it's well possible that the bigger parts rip themselves off sooner.

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Is it OK to replace a 750 ohm 5W ceramic resistor with a 750 ohm 10W ceramic resistor?

Yes.

Will the 10W one generate more heat?

No.

Is it OK to mix one 10W resistor with three (existing) 5W resistors? (All 750 ohms and 5% tolerance.)

Yes.

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    \$\begingroup\$ I am sorry, don't they ban for short answers here? :) \$\endgroup\$
    – user76844
    Commented Jan 26, 2017 at 21:13
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    \$\begingroup\$ Everyone else, sure, but not when it's Olin ;-) \$\endgroup\$ Commented Jan 26, 2017 at 21:41
  • \$\begingroup\$ He should change to Odin \$\endgroup\$
    – user76844
    Commented Jan 26, 2017 at 21:49
  • \$\begingroup\$ @Gregory: This answers clearly and exactly what the OP asked. If that doesn't result in the OP getting what he wants, then that's on him for not asking the right question. \$\endgroup\$ Commented Jan 27, 2017 at 11:32
  • \$\begingroup\$ I am completely with you on this. Hope moderators wiil not punish me- i same cases i was voted down and my answers were deleted. \$\endgroup\$
    – user76844
    Commented Jan 27, 2017 at 13:22

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