jamrock
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Post by jamrock on Sept 3, 2012 17:35:50 GMT -5
But would not heat creation dependent on the efficiency of the amplifier. I would think that the greater the efficiency, the lesser power is dissipated as heat. Therefore, if the XPA-1L is more efficient than the XPA-1, despite having more class A amperage, it would give off less heat than the XPA-1. No?
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stiehl11
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Post by stiehl11 on Sept 3, 2012 17:38:01 GMT -5
But would not heat creation dependent on the efficiency of the amplifier. I would think that the greater the efficiency, the lesser power is dissipated as heat. Therefore, if the XPA-1L is more efficient than the XPA-1, despite having more class A amperage, it would give off less heat than the XPA-1. No? No. Class A is the most inefficient speaker class there is. That's one of the reasons why engineers made the sacrifice to Class A/B. |
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jamrock
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Post by jamrock on Sept 3, 2012 17:53:30 GMT -5
Yes. I agree that while class A is the most linear and most inefficient, class A/B maxxes out at about 70% efficiency as well and dumps about 1/3 of its output as heat. Most A/B amps on the market achieve tops 67% efficiency. Therefore, my thinking was that the closer an A A/B amp gets to its maximun efficency, the less heat it will deposit. But I do yield to superior knowledge.
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Post by dean70 on Sept 3, 2012 17:59:11 GMT -5
I remember back in the 90's I had a Denon stereo amp that ran what Denon termed Class A+, which was moderate power Class A which switched the bias current down with a high speed optically coupled bias circuit for high power Class A/B once the power was over a certain point.
Is the XPA-1L fixed or variable bias?
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stiehl11
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Post by stiehl11 on Sept 3, 2012 18:10:30 GMT -5
The XPA-1L is temperature controlled or controlled by a switch. In Class A mode, if the temperature exceeds a set point it starts to "throttle back" the available Class A wattage to a point that it can become completely Class A/B on its own. However, if the user does not wish to run in Class A they can flip a switch in the back and run completely in Class A/B from (almost) the 1st watt.
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Post by kzone on Sept 3, 2012 19:18:23 GMT -5
The XPA-1L is basically 1/2 the output power of the XPA-1. The XPA-1L was said to have 250w into 8 ohms, and 500w (or very close to it) into 4 ohms at Emofest. I read somewhere on this board, maybe this thread, that the target price is $699. I was under the impression this weekend that was less than that - $550 to $599. And to clarify my statement at 60 watts the XPA-1 was a lot hotter than the XPA-1L. 60 watts of heat is 60 watts of heat. 30 watts of heat is 30 watts of heat. It's analogous, not exactly, to a light bulb. 60w on the XPA1? I meant why would it be too hot for the XPA1 to have 30w when it's ok for the XPA1L to have 30w? Or do u mean that the heat becomes the issue when considering the 500w AB power the XPA1 has? DYohn mentioned about better heat management on the 1L, whic answer my question but will still leave me wondering why this better heat management couldn't be deployed on the XPA1. There are many higher powered pure class A amps out there too so it should not require some great discovery to deal with the heat issue. I'm not saying the XPA1 has suddenly become bad just because the XPA1L is announced, just want to understand better |
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Post by paintedklown on Sept 3, 2012 19:30:44 GMT -5
Very interesting indeed. I had been intrigued by the Nelson Pass amps, but wasn't going to spend that kind of coin anytime soon, especially before I get my speakers. Given Emo's 30 day return policy, i might have to audition these against my regular XPA-1s. The Ls take up less space than my big boys and depending on resale value at the time, I might be able to trade straight across. Mark If you do decide to do this, please post a thread with your A/B results. I too have a pair of XPA-1s, but these XPA-1Ls running in class A mode, may best them in SQ...then again, I may now have the ears to hear it.   I am certainly intrigued, either way.  |
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stiehl11
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Post by stiehl11 on Sept 3, 2012 20:20:15 GMT -5
And to clarify my statement at 60 watts the XPA-1 was a lot hotter than the XPA-1L. 60 watts of heat is 60 watts of heat. 30 watts of heat is 30 watts of heat. It's analogous, not exactly, to a light bulb. 60w on the XPA1? I meant why would it be too hot for the XPA1 to have 30w when it's ok for the XPA1L to have 30w? Or do u mean that the heat becomes the issue when considering the 500w AB power the XPA1 has? DYohn mentioned about better heat management on the 1L, whic answer my question but will still leave me wondering why this better heat management couldn't be deployed on the XPA1. There are many higher powered pure class A amps out there too so it should not require some great discovery to deal with the heat issue. I'm not saying the XPA1 has suddenly become bad just because the XPA1L is announced, just want to understand better The XPA-1 is twice the wattage as the XPA-1L. The same system that was developed for the XPA-1 to run in Class A up to 60 watts was scrapped because the XPA-1 would run too hot in Lonnie's words. That system was incorporated in a "pet project" that eventually became the XPA-1L. It was simply unused tech that was repurposed in the XPA-1L. Because the XPA-1L is half the wattage of the XPA-1 it only runs the first 30 watts in Class A as opposed to the first 60 watts. 30 watts is less power, and therefore less heat generated, than the 60 watts of Class A in the XPA-1 that would be available using this technology. So yes, the heat management that is on the XPA-1L can be implemented on the XPA-1. It will control it to 60 watts; which is too hot according to Lonnie. If you want to control the XPA-1 to 30 watts Class A it would take an engineer to design it and implement it, as well as the additional cost of the components involved. It is not impossible but something like this is not something you toss off under a shade tree in an afternoon. If you want "off-the-shelf" technology then be prepared to pay the licensing fee for the proprietary technology you're going to be using. It would be common sense to understand that to control an amp to Class A at an incremental lower percentage would cost an incremental increase in the net cost of the amp. This is why pure Class A amps generally cost a lot of money compared to Class A/B amps of similar wattage. Everything Emotiva does cost money. Emotiva is in business to make money while providing a product to the public. If Emotiva decides that it would be difficult to make money with a certain product they won't build it. |
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Post by garbulky on Sept 3, 2012 20:37:19 GMT -5
Correct but what an amazing deal would be 60 watts of class A per channel?
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Post by Dark Ranger on Sept 3, 2012 21:57:10 GMT -5
OK, I will admit all the talk about this new product is causing me to seriously rethink my plans about the XPA-200. I was dead-set on buying it, but this XPA-1L is just mouth-watering. For me, the biggest drawbacks about this amp include: - Class A inefficiency = 30 watts X 2 amps = 60 watt space heater in my office - Class A inefficiency = wasted electricity doing nothing. I live in FL. The electric bill is already high enough. - breaks my budget for two-channel amplification - would have to buy another shelf for my rack On the other hand, the biggest advantages about this amp include: - Class A sound quality and performance. 'Nuff said. - Class A/A-B operating mode switch - likely a "last amp you'll ever need" with monoblock bragging rights - small form-factor is a big plus - reasonable price for quality monoblocks - balanced/differential amp (compared to the XPA-200) If this amp did not have an A/A-B operating mode switch, I'd probably pass it by. However, the ability to run in either mode is a fantastic option. So I could effectively use A-B mode to keep down the heat, and switch to A mode for SQ and critical listening. But if I keep it in A-B mode often, why not just go with the regular amps instead? This will require more thought. |
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Post by kzone on Sept 3, 2012 22:06:40 GMT -5
60w on the XPA1? I meant why would it be too hot for the XPA1 to have 30w when it's ok for the XPA1L to have 30w? Or do u mean that the heat becomes the issue when considering the 500w AB power the XPA1 has? DYohn mentioned about better heat management on the 1L, whic answer my question but will still leave me wondering why this better heat management couldn't be deployed on the XPA1. There are many higher powered pure class A amps out there too so it should not require some great discovery to deal with the heat issue. I'm not saying the XPA1 has suddenly become bad just because the XPA1L is announced, just want to understand better The XPA-1 is twice the wattage as the XPA-1L. The same system that was developed for the XPA-1 to run in Class A up to 60 watts was scrapped because the XPA-1 would run too hot in Lonnie's words. That system was incorporated in a "pet project" that eventually became the XPA-1L. It was simply unused tech that was repurposed in the XPA-1L. Because the XPA-1L is half the wattage of the XPA-1 it only runs the first 30 watts in Class A as opposed to the first 60 watts. 30 watts is less power, and therefore less heat generated, than the 60 watts of Class A in the XPA-1 that would be available using this technology. So yes, the heat management that is on the XPA-1L can be implemented on the XPA-1. It will control it to 60 watts; which is too hot according to Lonnie. If you want to control the XPA-1 to 30 watts Class A it would take an engineer to design it and implement it, as well as the additional cost of the components involved. It is not impossible but something like this is not something you toss off under a shade tree in an afternoon. If you want "off-the-shelf" technology then be prepared to pay the licensing fee for the proprietary technology you're going to be using. It would be common sense to understand that to control an amp to Class A at an incremental lower percentage would cost an incremental increase in the net cost of the amp. This is why pure Class A amps generally cost a lot of money compared to Class A/B amps of similar wattage. Everything Emotiva does cost money. Emotiva is in business to make money while providing a product to the public. If Emotiva decides that it would be difficult to make money with a certain product they won't build it. very well explained! Thank you so much!  |
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Post by kzone on Sept 3, 2012 22:11:11 GMT -5
This will require more thought. there... these are all that matters! Your own thoughts : - Class A sound quality and performance. 'Nuff said. - Class A/A-B operating mode switch - reasonable price for quality monoblocks - balanced/differential amp (compared to the XPA-200) |
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stiehl11
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Post by stiehl11 on Sept 3, 2012 23:11:59 GMT -5
The XPA-1 is twice the wattage as the XPA-1L. The same system that was developed for the XPA-1 to run in Class A up to 60 watts was scrapped because the XPA-1 would run too hot in Lonnie's words. That system was incorporated in a "pet project" that eventually became the XPA-1L. It was simply unused tech that was repurposed in the XPA-1L. Because the XPA-1L is half the wattage of the XPA-1 it only runs the first 30 watts in Class A as opposed to the first 60 watts. 30 watts is less power, and therefore less heat generated, than the 60 watts of Class A in the XPA-1 that would be available using this technology. So yes, the heat management that is on the XPA-1L can be implemented on the XPA-1. It will control it to 60 watts; which is too hot according to Lonnie. If you want to control the XPA-1 to 30 watts Class A it would take an engineer to design it and implement it, as well as the additional cost of the components involved. It is not impossible but something like this is not something you toss off under a shade tree in an afternoon. If you want "off-the-shelf" technology then be prepared to pay the licensing fee for the proprietary technology you're going to be using. It would be common sense to understand that to control an amp to Class A at an incremental lower percentage would cost an incremental increase in the net cost of the amp. This is why pure Class A amps generally cost a lot of money compared to Class A/B amps of similar wattage. Everything Emotiva does cost money. Emotiva is in business to make money while providing a product to the public. If Emotiva decides that it would be difficult to make money with a certain product they won't build it. very well explained! Thank you so much! All that said... the XPA-1 is still 10 watts Class A! So, if you have very efficient speakers (or you don't drive your inefficient speakers too hard), 10 watts will be all you need (if Class A is your bag). |
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Post by wrinklemash on Sept 4, 2012 0:25:20 GMT -5
very well explained! Thank you so much! All that said... the XPA-1 is still 10 watts Class A! So, if you have very efficient speakers (or you don't drive your inefficient speakers too hard), 10 watts will be all you need (if Class A is your bag). Yep, and there about 15 XPA-1 B-stocks left late Sunday afternoon at Emofest. $799 ea.....hmmmm |
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Post by garbulky on Sept 4, 2012 2:11:17 GMT -5
OK, I will admit all the talk about this new product is causing me to seriously rethink my plans about the XPA-200. I was dead-set on buying it, but this XPA-1L is just mouth-watering. For me, the biggest drawbacks about this amp include: - Class A inefficiency = 30 watts X 2 amps = 60 watt space heater in my office - Class A inefficiency = wasted electricity doing nothing. I live in FL. The electric bill is already high enough. - breaks my budget for two-channel amplification - would have to buy another shelf for my rack On the other hand, the biggest advantages about this amp include: - Class A sound quality and performance. 'Nuff said. - Class A/A-B operating mode switch - likely a "last amp you'll ever need" with monoblock bragging rights - small form-factor is a big plus - reasonable price for quality monoblocks - balanced/differential amp (compared to the XPA-200) If this amp did not have an A/A-B operating mode switch, I'd probably pass it by. However, the ability to run in either mode is a fantastic option. So I could effectively use A-B mode to keep down the heat, and switch to A mode for SQ and critical listening. But if I keep it in A-B mode often, why not just go with the regular amps instead? This will require more thought. You make some good points. However...keep in mind a 60 watt old school light bulb doesn't actually throw off that much heat or is very bright to begin with. So the equivalent cost of fantastic audio is a weak light bulb  Your electricity bill is mostly the AC and the drier, heater units etc. It does take a good amount of power to heat up a room and 60 watts is really not that bad nor is it a whole lot of power. For instance a decent graphics card in a computer may give off more heat than two xpa-1 l's. Mine used to give off about a 120 watts of heat and a lot of cards will easily consume 2 to 300 watts of power. Hope that helps in making your decision. |
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Post by kzone on Sept 4, 2012 5:36:09 GMT -5
All that said... the XPA-1 is still 10 watts Class A! So, if you have very efficient speakers (or you don't drive your inefficient speakers too hard), 10 watts will be all you need (if Class A is your bag). Im using the Penaudio Sinfonia, they need quite abit of power & current. It's normal for the XPA1 lights to cross midway but I normally off the leds so it's not distracting. |
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harri009
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Post by harri009 on Sept 4, 2012 6:55:57 GMT -5
As far as heat, Pass amps say they all idle at 127F. I wonder what idle temp Lonnie is trying to avoid
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Post by kzone on Sept 4, 2012 7:45:44 GMT -5
Harri009, u paired the Ayre K5xe with UPA2? Why not a balanced amp?
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harri009
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Post by harri009 on Sept 4, 2012 8:24:28 GMT -5
Harri009, u paired the Ayre K5xe with UPA2? Why not a balanced amp? Just waiting on the moolaa  |
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bootman
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Post by bootman on Sept 4, 2012 8:47:42 GMT -5
Just in case anyone was wondering, most tube amps run in class A.
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Your electricity bill is mostly the AC and the drier, heater units etc. It does take a good amount of power to heat up a room and 60 watts is really not that bad nor is it a whole lot of power. For instance a decent graphics card in a computer may give off more heat than two xpa-1 l's. Mine used to give off about a 120 watts of heat and a lot of cards will easily consume 2 to 300 watts of power. 
