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Post by subdusted on Apr 21, 2013 3:56:00 GMT -5
Looked at XPA-1L specs and they just don't seem right.
500 watts @ 4 ohm (0.1% THD)
450 VA heavy duty toroidal transformer
How is this actually possible?
Another thing that bothers me is 35 watts in cllass A. This would produce so much heat that with no active ventilation you could make toasts on the amp.. The description says it just gets slightly warmer.
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Post by garbulky on Apr 21, 2013 6:22:57 GMT -5
It would be hot. BTW, the specs are going to be better (not sure what specs) since the fix to the buzzing issue improved the test results.
Very nice! I was wondering about the power supply but there's also capacitance to think of I guess.
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bootman
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Post by bootman on Apr 21, 2013 7:28:44 GMT -5
If you are worried about heat, DONT get a class A amp!!!
Educate yourself on the different amp classes first.
Then the specs may make more sense to you.
Example: how does class D amps make 400W with no transformer and a small switching power supply?
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Post by doc1963 on Apr 21, 2013 7:30:25 GMT -5
If there's one thing that Emotiva does extremely well, it's design amps. So, I would think that the specs are quite kosher. While a 450 VA toroidal transformer may seem small in comparison to some of their other amps, there is also 90,000 uF of secondary capacitance which is quite large, so I don't see where the ability to produce the spec'd output would be a problem whatsoever. Yes, producing the first 35 watts in "Class A" will produce more heat, but if one allows adequate "breathing room" around the amp, that alone should not harm the amp. Additionally, there is an onboard microprocessor that will monitor the internal conditions along with the incoming signal requirements and automatically (and seemlessly) switch into A/B mode when any thresholds are crossed. Personally, I was all set to purchase a pair of XPA-1s until this amp was mentioned as being "in the works" late last year. Since there was a prototype shown and the specs discussed at Emofest, I decided to put my amp purchase "on hold" until these became available and user feedback could be considered. These amps are now on my " very short list" along with the XPA-1. I'll likely wait until I hear some feedback (preferably from those who have also owned the XPA-1) before deciding between the two.....  |
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Post by ocezam on Apr 21, 2013 9:06:59 GMT -5
Another thing that bothers me is 35 watts in cllass A. This would produce so much heat that with no active ventilation you could make toasts on the amp.. The description says it just gets slightly warmer. Pass Labs produces amps with up to 400 watts of class A. I don't think any of their amps have active ventilation. .. |
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Post by ocezam on Apr 21, 2013 9:07:30 GMT -5
If there's one thing that Emotiva does extremely well, it's design amps. So, I would think that the specs are quite kosher. No doubt. ... |
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Post by garbulky on Apr 21, 2013 10:31:37 GMT -5
Another thing that bothers me is 35 watts in cllass A. This would produce so much heat that with no active ventilation you could make toasts on the amp.. The description says it just gets slightly warmer. Pass Labs produces amps with up to 400 watts of class A. I don't think any of their amps have active ventilation. .. The pass chassis are also a completely different ball game. But I have little worry that the xpa-1 L's will be too hot or go out of class A mode too soon. It happened once and I doubt they'll mess up on the third release. |
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Post by ocezam on Apr 21, 2013 11:10:01 GMT -5
Pass Labs produces amps with up to 400 watts of class A. I don't think any of their amps have active ventilation. .. The pass chassis are also a completely different ball game. No kidding. We're talking 35w here. .. |
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Post by Dan Laufman on Apr 21, 2013 11:38:31 GMT -5
The 450 VA rating on transformer is more than adequate for this amplifier.
You need to remember something; it's called duty cycle.
It's is not powering a light bulb or a toaster with a 100% duty cycle. It's powering an amplifier with a typical home use duty cycle of 5-20% when driving speakers with a music signal.
Sure, we can put a larger transformer in the unit and make it larger, heavier, and costlier; but to what end? I doesn't need it to make its specifications.
We provide the most complete test data of any manufacturer I know of. We show our products performance using the finest test and measurement system available today in order to give you the complete, unvarnished story as it relates to performance.
Why don't other makers do this?? Our products are the real thing, as our tens of thousands of satisfied customers can attest to. We welcome comparison with anyone's products.
The XPA-1L does exactly what we claim it does, and more.
End of discussion.
Cheers
Big Dan
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Post by milt99 on Apr 21, 2013 16:23:37 GMT -5
I know Big Dan said "end of discussion", but I'd like to add some more  There are multiple ways to design an amp that does what the XPA-1L does. It's all about how the different components work together that makes the sum total of the final performance specs and sound. Some amps could have larger transformers, less capacitance and fewer transistors or any combo of the above. Personally and FWIW, I'm kind of an ampliphile(?) and I like what I see inside the XPA-1L. Beefy transformer, decent capacitance and lots of transistors. I would like to see maybe a third more capacitance but in reality I'm no amp designer not even in the ballpark. It's more of a more is better POV that has no basis in fact but a personal bias. Just to be clear, I have no doubt as to the veracity of Emotiva's published specs for several reasons. Foremost, from my brief experience with Emotiva, fudging specs doesn't jibe with everything else they do as a company. Emotiva isn't stupid. Any decent review is going to bench test the amp and push it to the limits and publish their results in comparison to the published specs. I've read reviews of Emotiva amps where the reviewer(s) are blown away by the performance specs AND the sound. I know that in the world of the Internet there are certain people who can't let facts get in the way of a personal bias. And once again for the record, I'm so happy I stumbled on to the XPA-1L announcement some months back as I was seriously looking at amps for my new 2-channel system. I was looking hard at Monarchy Audio 100 SE and Pass Labs XA-30.5 among others. I saw XPA-1L specs and jumped for joy. Wow, it was like I put in a wishlist for a mono-amp and somebody at Emotiva built it and for an affordable(unreal) price just for me. |
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Post by audiofile on Apr 21, 2013 20:42:45 GMT -5
My XPA-1's run almost all day on any day I am home and will run 4 - 6 hours a day at the minimum and they barely get warm, even when the listening level is turned up from time to time.
I do not have any cooling employed other than normal air circulation in the room and I provide them the amount of airspace recommended in the manual.
I can't seem to get them hot. I don't think I'd be able to be in the same room if I were to try and heat them up. The levels and sound pressure needed to get there would be murder to my ears.
So I may not understand all the niceties of the design, the math and the build requirements but from a practical application standpoint, my XPA-1's do what they are designed to do without being on the edge of failure when they do it.
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Post by garbulky on Apr 22, 2013 7:49:22 GMT -5
Plus don't forget the 5 year transferrable warranty. That means that emotiva warranties this product no matter how badly it's been placed, or how many trips in uncertain rides and box tosses it takes to get to its first, second, and even third owners. So they have to build something that isn't on the edge of failing or it will eat right into their profits.
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Post by sergeantynot on Apr 22, 2013 9:58:58 GMT -5
Lonnie mentioned over in the XPA-1L thread that the specs are actually improved...I'm looking forward to seeing what they come out as. That might be a game changer over the XPA-2 then.
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Post by mgm on Apr 22, 2013 15:38:56 GMT -5
While I don't doubt the XPA-1L can deliver the power as claimed, it is obviously not going to be continuous power. I doubt any speaker or your ears can withstand that kind of continuous power anyway.
However, since it appears to rely heavily on the storage caps, I'm wondering how the power is going to degrade as the caps age. Electrolytic capacitors are well-known to degrade after 5-10 years (increase in ESR...etc.) Using more caps rather than a larger transformer is probably more economical, but I'll be curious about the design lifetime of these amps.
On a side note, I just replaced the bias LEDs on my 20 year-old tube amps. I never expected that the original tubes actually lasted longer than the LEDs...
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bootman
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Post by bootman on Apr 22, 2013 16:55:24 GMT -5
While I don't doubt the XPA-1L can deliver the power as claimed, it is obviously not going to be continuous power. Sigh, What is your definition of "continuous power"? Now before you answer that, what audio device do you know of that actually can do this in the way that you think continuous power means? (and please post test results that actually show this) Seriously, think about that for a bit before answering. |
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Post by deltadube on Apr 22, 2013 17:07:46 GMT -5
If there's one thing that Emotiva does extremely well, it's design amps. So, I would think that the specs are quite kosher. While a 450 VA toroidal transformer may seem small in comparison to some of their other amps, there is also 90,000 uF of secondary capacitance which is quite large, so I don't see where the ability to produce the spec'd output would be a problem whatsoever. Yes, producing the first 35 watts in "Class A" will produce more heat, but if one allows adequate "breathing room" around the amp, that alone should not harm the amp. Additionally, there is an onboard microprocessor that will monitor the internal conditions along with the incoming signal requirements and automatically (and seemlessly) switch into A/B mode when any thresholds are crossed. Personally, I was all set to purchase a pair of XPA-1s until this amp was mentioned as being "in the works" late last year. Since there was a prototype shown and the specs discussed at Emofest, I decided to put my amp purchase "on hold" until these became available and user feedback could be considered. These amps are now on my " very short list" along with the XPA-1. I'll likely wait until I hear some feedback (preferably from those who have also owned the XPA-1) before deciding between the two..... im waiting for some feed back too.. what would happen if everyone waited tho.. nice to see big Dan come out .. im really tempted to buy 2 of these.. but im a bit scared too yet cheers |
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Lsc
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Post by Lsc on Apr 22, 2013 17:25:13 GMT -5
It seems like Big Dan is just making it 100% clear that the specs are not embellished in any way, shape or form and if you owned any other Emotiva amp, you know if anything, they error on the side of caution.
They have test lab results for each amp that they sell. LOL. The answer is right there...in front of your face.
They didn't break out the class A portion, but maybe they will given the issues at the introduction.
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Post by garbulky on Apr 22, 2013 17:30:38 GMT -5
Don't jump on the poor guy for a legitimate question....
I wonder what is their definition of constant power output? Till the capacitors run out?
Anyway, I'm not very worried about it. I have no doubt it actually tests out as the AP specs say it does and pumps out those watts.
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bootman
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Post by bootman on Apr 22, 2013 17:58:53 GMT -5
Don't jump on the poor guy for a legitimate question.... I wonder what is their definition of constant power output? Till the capacitors run out? Anyway, I'm not very worried about it. I have no doubt it actually tests out as the AP specs say it does and pumps out those watts. Yeah, I may have jumped on him a bit hard, but people need to realize that amps are not designed like light bulbs! Music is not a continuous sine wave, speakers are not simple resistors (ok maybe maggies are close but I digress) and everyone forgets about time!!!! <loud heavy breathing> Ok, I'm done for now.  |
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DYohn
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Post by DYohn on Apr 22, 2013 18:13:59 GMT -5
Again, it comes down to non-engineers who don't really understand the specs they are reading or how to interpret yet they try to pass judgement on specs they know very little about. It seems to happen a lot on this forum - and on many others including some who pretend to be about "science.". Mr. Laufman has properly answered the question. Any further questioning simply demonstrates lack of understanding.
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