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Post by odedia on Feb 10, 2021 7:11:50 GMT -5
So after a week of usage, the situation appears to be as follows:
In Class A/B mode, Amp #1 remains literally cool to the touch, barely any heat being dissipated. Amp #2 runs warm, but nothing to worry about. My only "concern" in this regard would actually be, why is Amp #1 never gets even a little warm? Perhaps that one is the problem and its bias is set incorrectly?
In Class A mode, both amps run quite hot. Amp #1 is hot, but I can put my hand on it for a reasonable time. Amp #2 is very hot, and I can only place my hand on it for a few seconds before it becomes uncomfortable.
Audio-wise - both sound fantastic. I merely worry about long-term sustainability and reliability in this setup.
If I have an electrician friend, how hard would it be for him to adjust the bias? Is there any reference diagram I can refer to to understand the process? I don't say I'll do it immediately, but would be nice to have it just in case.
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cawgijoe
Emo VIPs 
"When you come to a fork in the road, take it." - Yogi Berra
Posts: 5,033
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Post by cawgijoe on Feb 10, 2021 11:01:09 GMT -5
So after a week of usage, the situation appears to be as follows: In Class A/B mode, Amp #1 remains literally cool to the touch, barely any heat being dissipated. Amp #2 runs warm, but nothing to worry about. My only "concern" in this regard would actually be, why is Amp #1 never gets even a little warm? Perhaps that one is the problem and its bias is set incorrectly? In Class A mode, both amps run quite hot. Amp #1 is hot, but I can put my hand on it for a reasonable time. Amp #2 is very hot, and I can only place my hand on it for a few seconds before it becomes uncomfortable. Audio-wise - both sound fantastic. I merely worry about long-term sustainability and reliability in this setup. If I have an electrician friend, how hard would it be for him to adjust the bias? Is there any reference diagram I can refer to to understand the process? I don't say I'll do it immediately, but would be nice to have it just in case. Contact Emotiva and ask them if they could provide you with a schematic and also point you in the direction for adjusting bias. Worth asking. |
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Post by leonski on Feb 10, 2021 13:24:17 GMT -5
So after a week of usage, the situation appears to be as follows: In Class A/B mode, Amp #1 remains literally cool to the touch, barely any heat being dissipated. Amp #2 runs warm, but nothing to worry about. My only "concern" in this regard would actually be, why is Amp #1 never gets even a little warm? Perhaps that one is the problem and its bias is set incorrectly? In Class A mode, both amps run quite hot. Amp #1 is hot, but I can put my hand on it for a reasonable time. Amp #2 is very hot, and I can only place my hand on it for a few seconds before it becomes uncomfortable. Audio-wise - both sound fantastic. I merely worry about long-term sustainability and reliability in this setup. If I have an electrician friend, how hard would it be for him to adjust the bias? Is there any reference diagram I can refer to to understand the process? I don't say I'll do it immediately, but would be nice to have it just in case. Contact Emotiva and ask them if they could provide you with a schematic and also point you in the direction for adjusting bias. Worth asking. If I wanted a new outlet installed, I'd call an Electrician. If i wanted the BIAS adjusted on an amplifier? I'd find an electronics technician. 2 different guys. And sure, the difference in temp IS based on BIAS. I think #2 is running a LITTLE warm and #1 a LITTLE cool. EMO may part with a schematic. You'll have to ask 'em. And for the correct bias value and test points. |
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Post by garbulky on Feb 10, 2021 14:12:31 GMT -5
So after a week of usage, the situation appears to be as follows: In Class A/B mode, Amp #1 remains literally cool to the touch, barely any heat being dissipated. Amp #2 runs warm, but nothing to worry about. My only "concern" in this regard would actually be, why is Amp #1 never gets even a little warm? Perhaps that one is the problem and its bias is set incorrectly? In Class A mode, both amps run quite hot. Amp #1 is hot, but I can put my hand on it for a reasonable time. Amp #2 is very hot, and I can only place my hand on it for a few seconds before it becomes uncomfortable. Audio-wise - both sound fantastic. I merely worry about long-term sustainability and reliability in this setup. If I have an electrician friend, how hard would it be for him to adjust the bias? Is there any reference diagram I can refer to to understand the process? I don't say I'll do it immediately, but would be nice to have it just in case. I think the only way you'll really know which amp is having a problem is sending it in for service but that's $$$ |
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Post by Ex_Vintage on Feb 10, 2021 22:58:09 GMT -5
In Class A mode, both amps run quite hot. Amp #1 is hot, but I can put my hand on it for a reasonable time. Amp #2 is very hot, and I can only place my hand on it for a few seconds before it becomes uncomfortable. As a general rule, if you can hold your had on it for only 5 seconds, its about 60 degrees C. That's on the cover, so the power amp output devices are getting much hotter (100+ deg C.). That level of heat will definitely reduce the life of the output semiconductors and the associated power capacitors are running in a high local ambient environment which will drastically reduce their lifetime. |
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Post by 405x5 on Feb 11, 2021 12:04:32 GMT -5
Hi, I just got a pair of XPA-1 Gen 2's (used). They sound wonderful. I'm a bit worried because I notice the one of them is considerably and consistently hotter then the other, in both Class A and Class A/B Mode (less hot in A/B). Any ideas what would be the reason for this? Anything I can do or test to prevent it? They both sound the same so I don't think there's any specific defect with it that I notice. ......Had you but one......wouldn’t have noticed! Bill |
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Post by leonski on Feb 11, 2021 20:01:32 GMT -5
In Class A mode, both amps run quite hot. Amp #1 is hot, but I can put my hand on it for a reasonable time. Amp #2 is very hot, and I can only place my hand on it for a few seconds before it becomes uncomfortable. As a general rule, if you can hold your had on it for only 5 seconds, its about 60 degrees C. That's on the cover, so the power amp output devices are getting much hotter (100+ deg C.). That level of heat will definitely reduce the life of the output semiconductors and the associated power capacitors are running in a high local ambient environment which will drastically reduce their lifetime. Are the caps in this amp.....at least the Big PS Cans, 85c or 105c rated? |
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Post by odedia on Mar 1, 2021 7:31:42 GMT -5
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Post by DavidR on Mar 1, 2021 19:45:25 GMT -5
As others mentioned: Bias and swapping wires is a good idea to rule that out. Is it the same side i.e. R or L?
Another possibility is speaker output relay/device.
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Post by leonski on Mar 4, 2021 22:12:15 GMT -5
A RELAY will make a 'ping' or 'click' noise when cycling. Does amp have relays?
Bias is still on the short list. I'd like to see the layout, but link above doesn't
HOME Theatere and Hi Fi in the review of the XPA1 G2 claims 90 watts at idle. This can be confirmed with a Kill-A-Watt meter, available for maybe 25$ on Amazon. And is accurate enough for this purpose.
Higher or lower by a LOT confirms bias issue. Or a high side / low side. Amp is 'differential' and based on the image I looked up, has 2 sets of output devices. Look at all that nice Heat Sinking!
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Post by frogman122 on Nov 28, 2021 18:48:20 GMT -5
OP,….
Did you get this all,remedied?
I would have brought to emotiva, and have them look at the amps, something is wrong.
Hope,all,went,well
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