5W R22J Resistor In Speaker, Need Replacement - diyAudio
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Old 2nd May 2013, 03:50 AM   #1
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Default 5W R22J Resistor In Speaker, Need Replacement

Is there a better resistor than these ceramic coil ones?
Doing a recap on my Emotiva Airmotiv6.

2cm length, 2cm height, 0.5cm width.
Two Leads.
Click the image to open in full size.

Would replace it with Mundorf M-Resist, but it's too big and costly.

Help would be appreciated.
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Old 2nd May 2013, 08:03 PM   #2
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These look like emitter resistors for an amplifier output stage.

Choose a similar wattage (wirewound, which is what these are) resistor with the lowest possible temperature coefficient. Vishay/Mills have good, low Tc. The existing resistors may not be easy to improve upon.
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Old 2nd May 2013, 08:49 PM   #3
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Thanks so much for commenting Damon.

I've did some looking around and it seems to be a cement ceramic wirewound resistor:
Aliexpress.com : Buy 0.22 5w cement resistor ceramic resistor on China Electronics Wholesale.

Is it ok to go over the wattage rating? (eg. 10W, 15W, 20W)

I'll be sure to look for some emitter resistors with the lowest temperature coefficient.

Do these generally get hot?
I've heard cases where some output stage resistors would melt or run into heating issues which doesn't do justice for sound quality.
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Old 2nd May 2013, 09:17 PM   #4
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Higher wattage won't change anything except the size of the part; it may not be possible to fit neatly.

If actually dissipating five watts, yes, they'll get rather warm. Normally, they should NOT get that hot. A discolored or smoking hot resistor is a sign of a problem elsewhere--resistors are passive devices and don't fail like this on their own. I would leave them as is; a replacement resistor ought to be spaced away from the board on it's own extended leads for better dissipation. No more than half an inch or so should do it.
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Old 2nd May 2013, 09:41 PM   #5
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Oh, so the only time WORTH replacing a resistor like this is if it's discolored or have an overly high temperature coefficient. i see i see.

Let's say i went with Mundorf M-Resist Supreme which is rated at 20W.
Being 50mm long, it's not going to have that "clean fit".

So i was thinking, is it okay to mount on top of each other (piggyback) or would it not be recommended since the leads are too long and can be distorted by EMI signals.
Click the image to open in full size.

Sorry for all the questions.
I'm doing a recap on my studio speakers (Emotiva Airmotiv6) and it's kind of a one-time thing. Just trying to get the best performance out of them since i'm not going to be buying/upgrading speakers for another 5-7 years.

So far i have replaced all Micon (Chinese brand) capacitors with Elna Silmic II, film capacitors (yellow/blue colored Chinese brand) with WIMA FKP2/MKP2 (some MKS2 as capacitance is too high).

Hope i'm doing it right. Your comments are highly taken into account.
I kept the same capacitance/voltage. The main improvement i'm going for with the film cap changes is swapping out those cheap Chinese polyesters with a higher polypropylene dielectric cap.
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Old 2nd May 2013, 09:56 PM   #6
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I really wouldn't change those resistors.
With SMD components on the board, the length of the resistor leads would be massive compared to the rest.
If your concerned about the heat, make up some new U shaped clamps for the output transistors, incorporate heatsinking and physical stability for the resistors.
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Old 2nd May 2013, 10:20 PM   #7
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I was mainly concern with the sound quality if changing them would present any sonic gains, but since it doesn't, it's most likely going to be left alone.

Underneath the PCB near the resistors, there are multiple MOSFETS or Output Transistors that are equipped to the large anodized heatsink (behind the speaker). I don't think heat would be an issue.

Thanks for the commenting whizgeek.
Guess there's no upgrades i can do other than changing out capacitors.
Perhaps changing out copper wires with pure silver is another upgrade.
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Old 3rd May 2013, 08:09 AM   #8
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There's a film capacitor that i can't seem to understand the value to.

"u22nJ2A"

Any ideas?

u22 is 0.22uF, that i know.
J is 5% tolerance.
Where does the n and 2A play in all this?
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Old 3rd May 2013, 07:28 PM   #9
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A hint on choosing quality wirewound resistors: 1% or better tolerance at these low values pretty much means very low Tc. I'd use Mills wirewounds since they're relatively compact for their wattage rating. Vishay/Dale also has good choices; I'm finding them on surplus market.
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Old 3rd May 2013, 07:40 PM   #10
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Hey Damon, can you give me an example somewhere on google or mouser?
I'm looking but don't think i found the right ones.

1% tolerance would be great since the regular for resistors i know of is usually 5%.
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