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Post by Ivanhoe on Nov 3, 2013 21:58:30 GMT -5
About a week ago, I got two XPA-1L and I love their sound. I find they sound much better than my UPA-1s. They have a much richer sound, more detail and better dynamics. My only concern is that they get really really warm in A/B mode at normal listening volumes. Around 75db. Note: My room temperature is around 65-70 degrees and its dimensions are 12 ft by 15 ft. The XPA-1L has a clearance of 9.5 inches from the top. I understand this amps are suppose to get hot in Class A mode and I am fine with that but in A/B mode I was expecting it to be as hot as my UPA-1 which barely gets warm to the touch at the same listening volumes. It fact, since the XPA-1L is a better amp with bigger power supply, heat sinks, capacitance etc, I was expecting it to be even cooler as it can be pushed harder than the UPA-1. I am sure there is a good technical reason for this difference and others may have the same concern. Can someone explain me why such a difference with the heat each unit puts out (XPA-1L vs UPA-1) in class A/B mode. Any feedback will be appreciated.
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Post by garbulky on Nov 3, 2013 22:17:09 GMT -5
Well the XPA-1 L is half an XPA-1 in half the space. The main difference that is the smaller power supply.
IT would make sense that it is significantly warmer than the UPA-1. The XPA-2 even in AB mode is also warmer than my UPA-2 during idle. However it shouldn't be just slightly cooler than it in class A mode. It should be significantly cooler. But if you aren't experiencing anything wierd you are probably fine. Just don't set it on carpet or anything like that and give it some room to breathe.
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Post by Ivanhoe on Nov 4, 2013 8:27:13 GMT -5
Yes my XPA-1L in class A/B do not get nearly as hot as in class A mode. In class A mode they get super hot. On the other hand in class A/B mode they are very warm to medium hot. Otherwise they work just fine and their sound is fantastic in either mode!!! I wonder if the reason why they get so much warmer than my UPA-1 has to do with a much higher A bias even when set in class A/B mode. Maybe someone from Emotiva can clear the air. Or should I say hot air. Ha Ha Ha.  |
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bootman
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Post by bootman on Nov 4, 2013 8:38:47 GMT -5
If heat was an issue why did you chose this type (high class A bias) amp?
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Post by solarrdadd on Nov 4, 2013 8:51:52 GMT -5
If heat was an issue why did you chose this type (high class A bias) amp? it sounds like he's saying he's surprised it gets as hot as it does and is wondering if that's normal. emotiva doesn't state at their amp product pages warnings about high heat or anything. i'd also gather he was hoping that other folks with that same amp might chime in on their experiences with them as well as maybe someone from emo too. but it's Monday morning and i haven't had any coffee yet so i could be waaaaaaaaaaay off!  |
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Post by Jim on Nov 4, 2013 9:09:11 GMT -5
Yes my XPA-1L in class A/B do not get nearly as hot as in class A mode. In class A mode they get super hot. On the other hand in class A/B mode they are very warm to medium hot. Otherwise they work just fine and their sound is fantastic in either mode!!! I wonder if the reason why they get so much warmer than my UPA-1 has to do with a much higher A bias even when set in class A/B mode. Maybe someone from Emotiva can clear the air. Or should I say hot air. Ha Ha Ha. What's the XPA-1L like when it's sitting idle in class *A/B* mode? It should be pretty cool. In idle, A/B should be cool (or slightly warm), in A it will be cooking (by design). If it's hotter than the UPA-1 in Class A/B while operating (not idle), I'd suspect that's just that the 1L is a bigger more powerful amp. |
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Post by Ivanhoe on Nov 4, 2013 9:26:42 GMT -5
Yes, I am aware that the XPA-1L in class A mode gets very hot and I am fine with that. My concern is with regard to A/B mode and the amount of heat they produce in A/B mode compared to my UPA-1 which just get slightly warm at the same volume level. In class A/B mode I was expecting my XPA-1L to produce the same or lower amount of heat than my UPA-1. I thought that since the XPA-1L is better and more powerful than my UPA-1 it will sweat less not more at the same volume level. I am probably missing something and I am sure this will be sorted out. I did not check how warm the XPA-1L gets sitting idle. I will check tonight after work. Again thanks for all the replies.
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Post by solarrdadd on Nov 4, 2013 9:31:17 GMT -5
since i don't own one and don't plan on it, how do you know when it's in class A vs A/B? is there some indicator that tells you when your in one or the other mode?
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Post by Jim on Nov 4, 2013 9:38:30 GMT -5
since i don't own one and don't plan on it, how do you know when it's in class A vs A/B? is there some indicator that tells you when your in one or the other mode? There is a switch on the front to set it to start in A/B, or to do up to 35W in A, then transition if needed:  |
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bootman
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Post by bootman on Nov 4, 2013 9:44:41 GMT -5
If heat was an issue why did you chose this type (high class A bias) amp? it sounds like he's saying he's surprised it gets as hot as it does and is wondering if that's normal. That is correct. High class A bias amps do run hotter than amps that are typical plain A/B amps. (1W or less class A before going to class A/B) Now I get that the OP didn't know this going in. The extra heat is normal. If cool temps are required other types of amps are better candidates like class H or class D etc. |
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Post by creimes on Nov 4, 2013 9:51:27 GMT -5
I have mine stacked with an extra spacer between them and they do get warmer in Class A/B than my UPA-1's or XPA-2 did and my XPA-5 Gen 2 does, Class A they get really warm as it actually can be painful to touch in certain areas, as of yesterday though I went and bought a cheap 10" desk fan that sits beside them in which keeps them way cooler.
Chad
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KeithL
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Post by KeithL on Nov 4, 2013 9:54:10 GMT -5
The temperature an amp "runs at" depends on how much power it is dissipating at the moment, its thermal mass, ventilation, and things like that.
When a Class A/B amp is idling, the power dissipation is determined by the bias - which is set by design, but is usually designed to vary as the amp warms up (usually it runs higher when the amp is cold so that it does warm up). When a Class A/B amp is running at moderate power levels, it is usually 60% - 70% efficient. When an XPA-1L is in Class A mode, the bias is much higher, so it gets warmer when idling. (On a test bench, at full output, it will run about the same temperature in either mode.)
You should also remember that the heat sinks are inside the amplifier, so you shouldn't judge how hot the amplifier is running by how warm it feels on the top of the case. It is the temperature AT THE HEAT SINKS that counts. Depending on the design of the amp, where the vents are, and how close the heat sinks are to the cabinet, it may feel quite different at the top cover. (Incidentally, electronic components all have recommended operating temperature limits, and there are safety limits - which we comply with - that determine how hot the case is allowed to get. As a guideline, most people say "it's hot enough to actually hurt to touch" at a temperature between 130 and 140 degrees F - which, in electronic component terms, isn't all that hot.) The XPA-1L should NEVER get hot enough at the case to actually burn you (but it may just reach the point where you say "ouch" if you hold your hand against the top right over the heat sinks for too long.).
The short answer to your question is that the units are designed differently, and so operate at different temperatures (especially when running relatively quietly). It is simply a characteristic that is specific to each amplifier design.
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Post by audiobill on Nov 4, 2013 10:22:57 GMT -5
I have mine stacked with an extra spacer between them and they do get warmer in Class A/B than my UPA-1's or XPA-2 did and my XPA-5 Gen 2 does, Class A they get really warm as I can actually burn my hand on them in certain areas, as of yesterday though I went and bought a cheap 10" desk fan that sits beside them in which keeps them way cooler. Chad So why do you stack them? To expedite replacement |
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Post by creimes on Nov 4, 2013 10:26:58 GMT -5
I have mine stacked with an extra spacer between them and they do get warmer in Class A/B than my UPA-1's or XPA-2 did and my XPA-5 Gen 2 does, Class A they get really warm as I can actually burn my hand on them in certain areas, as of yesterday though I went and bought a cheap 10" desk fan that sits beside them in which keeps them way cooler. Chad So why do you stack them? To expedite replacement They sit where my XPA-2 used to be, it is the only spot I have for them, that is why I have the fan there for when I am wanting to use the Class A  Chad This pic is before I added 1.5 inches between the two amps  |
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Post by audiobill on Nov 4, 2013 10:37:53 GMT -5
So why do you stack them? To expedite replacement They sit where my XPA-2 used to be, it is the only spot I have for them, that is why I have the fan there for when I am wanting to use the Class A Chad This pic is before I added 1.5 inches between the two amps Why not add a shelf to that nice rack? |
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Post by creimes on Nov 4, 2013 10:42:09 GMT -5
[/quote]Why not add a shelf to that nice rack?[/quote]
That means I would have to take the whole rack down and I'm lazy to do that and most importantly don't have much spare time for it either lol, maybe one day as I do have extra MDF for it, but it's just a lot of work to do right now and the fan does it's job for now, I might have some spare time this coming weekend but I wanted to get some acoustic panels made as well.
Chad
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Post by Ivanhoe on Nov 4, 2013 12:18:42 GMT -5
So basically, it is o.k. and normal that my XPA-1L are running hotter in "class A/B mode" than my UPA-1 due to the way they are design. Thanks for the prompt reply Keith. Much appreciated !!!
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Post by dac0964 on Nov 4, 2013 13:01:08 GMT -5
Ivanhoe,
I experience the same with my 1Ls compared to my previous UPA-200. When I leave the 1Ls in idle even when they are switched to A/B, they are warmer than the UPA-200. So you're good.
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Post by deltadube on Nov 4, 2013 16:18:34 GMT -5
They sit where my XPA-2 used to be, it is the only spot I have for them, that is why I have the fan there for when I am wanting to use the Class A Chad This pic is before I added 1.5 inches between the two amps Why not add a shelf to that nice rack? Hi Chad ... looks like one amp has the film on and one has film off.. i like my amps with the film off the window cheers |
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Post by creimes on Nov 4, 2013 16:32:56 GMT -5
no no no no no no no no film on those babies Bob
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