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Post by fbczar on Oct 28, 2014 9:59:46 GMT -5
Keith, To follow up on the HomeTheaterHiFi.com review of the XPA-1 this is directly from the review: In both Class A and A/B modes I could also hear a slight hiss from the tweeter. It was very low level, and I had to be close to the speaker, but it was there. It was low enough that I couldn’t hear it in use unless the music was in between tracks. The review states either an Anthem MRX510 or Marantz AV7005 preamp and Revel F208 speakers were used. If the XPA-1 has slight audible hiss between tracks and it has an A weighted SNR of 89Db and the XPA-2 has an A weighted SNR of 97 would it follow that under like circumstances the XPA-2 would not produce an audible hiss? At what A weighted SNR would it be possible to assume that no audible hiss could exist? Thanks
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KeithL
Administrator 
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Post by KeithL on Oct 28, 2014 11:51:06 GMT -5
I'd love to give you a simple answer - but I can't - because there isn't one.  When I put up my last post on this subject, I was talking about different amplifiers under similar conditions; however, in reality, that's rarely the case. Speakers can vary by up to 20 dB or so in efficiency. Even beyond that, since speakers are rarely totally flat, if one speaker has a slight bump at 3 kHz, while another has a slight dip, that could add another 10 dB of difference between them at that frequency (as far as hearing hiss, all that matters is how efficient the speaker is at the frequencies that we hear as annoying hiss; everybody seems to agree that our hearing is most sensitive between about 3.5 kHz and 4 kHz). A room with a carpet will tend to absorb high-frequency noise, while one with lots of glass will bounce it around - possibly accounting for another 10 dB or more difference in how audible the hiss is. And, ignoring all that, the single biggest factor is background noise. Our ears have the biological equivalent of a very effective automatic gain control system. In a totally quiet room, in the middle of the night, with nothing running in the house, you can probably hear your own breathing, and even your heartbeat. At those times, you'd also be hearing hiss - from any amplifier - no matter how quiet it is. I read about one study years ago... there was a certain library that had been built to be super quiet. They had sound absorbers in the air ducts; everything was carpeted; even the fluorescent lights were special ones that didn't hum. Surprisingly, even though the room measured as being very quiet, people complained that it was very noisy and distracting. Why? Because, since there was virtually no background noise, you could hear every rustle of a book page; you could even hear other people moving around; and even breathing. When you entered the room, your ears adjusted to the quiet by "cranking up their gain". The room literally "was so quiet you could hear a pin drop" - and nobody really wants to hear a pin drop. The solution was to remove some of the sound dampening from the ventilators - at which point the gentle whirring hissing of the ventilators produced enough background noise to cause people's ears to reduce their sensitivity. After they did that, the room measured noisier, but sounded much quieter. Normally, when we listen to music, our ears adjust to the level of the music. Not only does the music actually cover up hiss and other noise that is many dB below the average level, but it also causes our ears to adjust to an appropriate sensitivity. This is why, when you're listening to music, you usually don't notice the hiss during the quiet spots. Then, when the music stops, our ears adjust to the normal background level of the room. Another thing you need to realize is that sound level drops as the square or cube of the distance you are from the speaker (which it is sort of depends on the speaker, the room, and the frequency involved). This means that it's downright silly to stick your ear in a tweeter - you should only worry about whether you can hear hiss from your normal listening position. (And, unless everything from your air conditioning to your electric clock is totally quiet, it only matters is that hiss is louder and more annoying than any other noises you hear anyway.) My point to all these facts is that, if you take a set of efficient speakers, put them in a live room, and listen in the middle of a quiet night, by putting your ear six inches from the tweeter, there is no amplifier ever made that won't hiss. What all this means is that, with "average" speakers, in an "average" room, you won't hear hiss in the quiet spots of your music with any amp with an S/N better than 80 dB or so. However, if you want to have it so you don't hear hiss, with efficient speakers, when the world is quiet, and you haven't been listening to music for a while (your ears adjust over several minutes), then it really depends on a lot of different factors - and they're all variable. I know you were hoping for a simple answer, but you aren't going to get it. Of course, there is another way to look at it..... A CD has a theoretical best possible S/N of 96 dB - so any amplifier that is quieter than that (relative to normal listening level; not relative to 1 watt) won't be contributing any noise when you listen to one. A 24 bit audio file can theoretically do 144 dB.... but, since no microphone or microphone preamp is anywhere near that quiet, you won't find recordings that quiet in real life. And, incidentally, vinyl, being optimistic, can reach a S/N of 70 dB or so ... Keith, To follow up on the HomeTheaterHiFi.com review of the XPA-1 this is directly from the review: In both Class A and A/B modes I could also hear a slight hiss from the tweeter. It was very low level, and I had to be close to the speaker, but it was there. It was low enough that I couldn’t hear it in use unless the music was in between tracks. The review states either an Anthem MRX510 or Marantz AV7005 preamp and Revel F208 speakers were used. If the XPA-1 has slight audible hiss between tracks and it has an A weighted SNR of 89Db and the XPA-2 has an A weighted SNR of 97 would it follow that under like circumstances the XPA-2 would not produce an audible hiss? At what A weighted SNR would it be possible to assume that no audible hiss could exist? Thanks |
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Post by Boomzilla on Oct 28, 2014 11:59:56 GMT -5
Let's see - just to tally up - I've now had the pleasure of owning:
XPA-2 (generatiion 1) - twice
XPR-2 once
Mini-X - twice
XPA-5 once
XPA-1L now
The most impressive of these will be difficult to pick. They all sounded similar, and within their power limitations, performed amazingly.
If I had to pick favorites, I'd say the first XPA-2 - It was the only amplifier that I'd tried that could tame the bass of the Thiel 3.6 speakers (a particularly difficult-to-drive speaker).
Another favorite would be the Mini-X. For its size and performance, I found it the equal to contenders far beyond its cost.
And finally, I'm floored by my current XPA-1Ls. With different sources, they can sound best in either Class-A or Class-AB mode, but they NEVER sound bad (understatement!).
Every time I think I've got a new toy that sounds better, I go back the the 1Ls and they surpass the best of the best that I compare them to. How Emotive does it for their prices is beyond me. I think I've finally got some understanding of the "mono-block club" on the Lounge. Y'all were RIGHT! LOL
Boomzilla
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Post by garbulky on Oct 28, 2014 12:29:27 GMT -5
Let's see - just to tally up - I've now had the pleasure of owning: XPA-2 (generatiion 1) - twice XPR-2 once Mini-X - twice XPA-5 once XPA-1L now The most impressive of these will be difficult to pick. They all sounded similar, and within their power limitations, performed amazingly. If I had to pick favorites, I'd say the first XPA-2 - It was the only amplifier that I'd tried that could tame the bass of the Thiel 3.6 speakers (a particularly difficult-to-drive speaker). Another favorite would be the Mini-X. For its size and performance, I found it the equal to contenders far beyond its cost. And finally, I'm floored by my current XPA-1Ls. With different sources, they can sound best in either Class-A or Class-AB mode, but they NEVER sound bad (understatement!). Every time I think I've got a new toy that sounds better, I go back the the 1Ls and they surpass the best of the best that I compare them to. How Emotive does it for their prices is beyond me. I think I've finally got some understanding of the "mono-block club" on the Lounge. Y'all were RIGHT! LOL Boomzilla You forgot the UPA-500  Also you've auditioned the UPA-2 and the UPA-1 briefly |
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Post by fbczar on Oct 28, 2014 12:40:45 GMT -5
Keith, I am going to buy an XMC-1. I have a B&K 7250 which is a 200 watt per channel A/B, five channel amp. I need two more channels of amplification for my front left and right speakers. Since the XMC-1 has balanced outputs would two XPA-1L's be a better choice than the XPA-2? I assume the XPA-1 would basically be a more powerful version of the XPA-1L, right?
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KeithL
Administrator
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Post by KeithL on Oct 28, 2014 13:59:11 GMT -5
Honestly, all of our amplifiers sound very good - and rather similar (in the big picture). Given your options, and that you really don't need as much power as the XPA-1's put out, I'd go with the XPA-1L's. I think they're one of the best sounding amps we've ever made; they've got plenty of power for what you're doing; and they're just a great deal right now. (Assuming you have the space, I'd always rather have a pair of monoblocks than a single two-channel amp.... just... because... well... they're MONOBLOCKS  ) Keith, I am going to buy an XMC-1. I have a B&K 7250 which is a 200 watt per channel A/B, five channel amp. I need two more channels of amplification for my front left and right speakers. Since the XMC-1 has balanced outputs would two XPA-1L's be a better choice than the XPA-2? I assume the XPA-1 would basically be a more powerful version of the XPA-1L, right? |
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moonwolf
Minor Hero
Audio is a great hobby
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Post by moonwolf on Dec 5, 2014 12:17:36 GMT -5
Hi Keith, Have you heard the new SA-250 yet? I had to make a very hard decision between a pair of XPA-1L's vs a single SA-250. XPA-1L's had better power, was cheaper, and already proven (extensively reviewed by many). But, I had a blind faith in Dan's podcast that SA-250's sound quality cannot even be touched by current amps. Now I'm eagerly waiting to receive mine, but just checking if anyone already have heard it. Honestly, all of our amplifiers sound very good - and rather similar (in the big picture). Given your options, and that you really don't need as much power as the XPA-1's put out, I'd go with the XPA-1L's. I think they're one of the best sounding amps we've ever made; they've got plenty of power for what you're doing; and they're just a great deal right now. (Assuming you have the space, I'd always rather have a pair of monoblocks than a single two-channel amp.... just... because... well... they're MONOBLOCKS ) Keith, I am going to buy an XMC-1. I have a B&K 7250 which is a 200 watt per channel A/B, five channel amp. I need two more channels of amplification for my front left and right speakers. Since the XMC-1 has balanced outputs would two XPA-1L's be a better choice than the XPA-2? I assume the XPA-1 would basically be a more powerful version of the XPA-1L, right? |
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Post by wilburthegoose on Jun 29, 2015 11:52:08 GMT -5
moonwolf - I received an SA-250 last week. I need to return it because it's entering protection mode with any type of significant load (I have zero doubt that its replacement won't have any issues).
But I did have a chance to play with it at low volume levels. In a word, it sounded amazing, and I can't wait to hear it when I can listen to it at higher volumes.
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Post by nickwin on Dec 28, 2015 11:11:00 GMT -5
Xpa5 gen 1, was it 1600 or 1200va? I'm seeing it listed as both online.
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Post by garbulky on Dec 28, 2015 11:47:04 GMT -5
1200 i think?
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Post by nickwin on Dec 28, 2015 11:54:46 GMT -5
I thought so too but I'm not sure. Here's XPA5 gen 1 specs from highfidelityreview.com, but maybe just a typo? The 4 ohm ratings did go down on the gen 2's so maybe this is the reason?
Specifications:
5 – independent mono blocks @ 200 wpc into 8 ohms; 350 wpc into 4 ohms
Class A/B design with short signal path
Triple Darlington with Toshiba output stages
Dual Differential input
Balanced (XLR) and Un-balanced (RCA)
Audiophile quality 5 way binding post
THD+N at rated power output: 0.007%
S/N ratio: >100db
10 to 120Khz (-3db) and 20 to 20 (with less than .15db deviation)
32db gain structure
1600VA toroidal transformer
60,000uF secondary capacitance
70 pounds
17” W x 7.75” H x 19” D
Price $799
I recently found out that my LPA1 has a 1200VA transformer as opposed to the 850VA in the UPA5, is it possible Emotiva was over engineering there amps a little more in the early days? Then again my UPA500 manual states that it has a 850VA transformer when its really 350, so mistakes do happen.
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Post by nickwin on Dec 29, 2015 17:18:06 GMT -5
Confirmed in an email. Gen 1 was 1200VA.
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Post by DavidR on Aug 12, 2018 16:24:33 GMT -5
Why do I need to sign into Google to view this PDF?
I want nothing to do with a Google Acct
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Post by AudioHTIT on Aug 12, 2018 19:23:06 GMT -5
Why do I need to sign into Google to view this PDF? I want nothing to do with a Google Acct What are you referring to that’s at least three years old? (this thread is 10 pages long) |
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Post by DavidR on Aug 12, 2018 19:28:15 GMT -5
Why do I need to sign into Google to view this PDF? I want nothing to do with a Google Acct What are you referring to that’s at least three years old? (this thread is 10 pages long) First post BUT if it's that old it may nit have been kept up to date. |
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Post by AudioHTIT on Aug 12, 2018 19:48:03 GMT -5
What are you referring to that’s at least three years old? (this thread is 10 pages long) First post BUT if it's that old it may nit have been kept up to date. Got it, we’ll that post is before my time, over 11 years old! 😮 |
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Post by leonski on Aug 12, 2018 21:47:44 GMT -5
I'd love to give you a simple answer - but I can't - because there isn't one. When I put up my last post on this subject, I was talking about different amplifiers under similar conditions; however, in reality, that's rarely the case. Speakers can vary by up to 20 dB or so in efficiency. Even beyond that, since speakers are rarely totally flat, if one speaker has a slight bump at 3 kHz, while another has a slight dip, that could add another 10 dB of difference between them at that frequency (as far as hearing hiss, all that matters is how efficient the speaker is at the frequencies that we hear as annoying hiss; everybody seems to agree that our hearing is most sensitive between about 3.5 kHz and 4 kHz). A room with a carpet will tend to absorb high-frequency noise, while one with lots of glass will bounce it around - possibly accounting for another 10 dB or more difference in how audible the hiss is. And, ignoring all that, the single biggest factor is background noise. Our ears have the biological equivalent of a very effective automatic gain control system. In a totally quiet room, in the middle of the night, with nothing running in the house, you can probably hear your own breathing, and even your heartbeat. At those times, you'd also be hearing hiss - from any amplifier - no matter how quiet it is. I read about one study years ago... there was a certain library that had been built to be super quiet. They had sound absorbers in the air ducts; everything was carpeted; even the fluorescent lights were special ones that didn't hum. Surprisingly, even though the room measured as being very quiet, people complained that it was very noisy and distracting. Why? Because, since there was virtually no background noise, you could hear every rustle of a book page; you could even hear other people moving around; and even breathing. When you entered the room, your ears adjusted to the quiet by "cranking up their gain". The room literally "was so quiet you could hear a pin drop" - and nobody really wants to hear a pin drop. The solution was to remove some of the sound dampening from the ventilators - at which point the gentle whirring hissing of the ventilators produced enough background noise to cause people's ears to reduce their sensitivity. After they did that, the room measured noisier, but sounded much quieter. Normally, when we listen to music, our ears adjust to the level of the music. Not only does the music actually cover up hiss and other noise that is many dB below the average level, but it also causes our ears to adjust to an appropriate sensitivity. This is why, when you're listening to music, you usually don't notice the hiss during the quiet spots. Then, when the music stops, our ears adjust to the normal background level of the room. Another thing you need to realize is that sound level drops as the square or cube of the distance you are from the speaker (which it is sort of depends on the speaker, the room, and the frequency involved). This means that it's downright silly to stick your ear in a tweeter - you should only worry about whether you can hear hiss from your normal listening position. (And, unless everything from your air conditioning to your electric clock is totally quiet, it only matters is that hiss is louder and more annoying than any other noises you hear anyway.) My point to all these facts is that, if you take a set of efficient speakers, put them in a live room, and listen in the middle of a quiet night, by putting your ear six inches from the tweeter, there is no amplifier ever made that won't hiss. What all this means is that, with "average" speakers, in an "average" room, you won't hear hiss in the quiet spots of your music with any amp with an S/N better than 80 dB or so. However, if you want to have it so you don't hear hiss, with efficient speakers, when the world is quiet, and you haven't been listening to music for a while (your ears adjust over several minutes), then it really depends on a lot of different factors - and they're all variable. I know you were hoping for a simple answer, but you aren't going to get it. Of course, there is another way to look at it..... A CD has a theoretical best possible S/N of 96 dB - so any amplifier that is quieter than that (relative to normal listening level; not relative to 1 watt) won't be contributing any noise when you listen to one. A 24 bit audio file can theoretically do 144 dB.... but, since no microphone or microphone preamp is anywhere near that quiet, you won't find recordings that quiet in real life. And, incidentally, vinyl, being optimistic, can reach a S/N of 70 dB or so ... Keith, To follow up on the HomeTheaterHiFi.com review of the XPA-1 this is directly from the review: In both Class A and A/B modes I could also hear a slight hiss from the tweeter. It was very low level, and I had to be close to the speaker, but it was there. It was low enough that I couldn’t hear it in use unless the music was in between tracks. The review states either an Anthem MRX510 or Marantz AV7005 preamp and Revel F208 speakers were used. If the XPA-1 has slight audible hiss between tracks and it has an A weighted SNR of 89Db and the XPA-2 has an A weighted SNR of 97 would it follow that under like circumstances the XPA-2 would not produce an audible hiss? At what A weighted SNR would it be possible to assume that no audible hiss could exist? Thanks I was speaking to a guy at an AIRSHOW. Not exactly a quiet place. I was wearing my Fitted Earplugs and wife had some sound attenuating over-ear headphones. But in talking about the IDIOTS running around the show with children on their shoulders with NO hearing protection on either, he let me in on a study. It seems that a 50 year old African Bushman ends up with BETTER HEARING than a Westerner 1/2 his age. We are immersed in a loud sound field from birth to death. No wonder a very quiet room seems LOUD. I was in a recording studio that was very inert. You could stand back-to-back with another person and almost couldn't hear them. Don't forget also that the SNR quoted is Best Case. SNR would seem to be lower at the very lowest powers and drop to some point than rise quickly. Link provided to a Threshold power amp. Skip down to figure 8 and figure 9 for THD vs Power. IMO, this is another reason NOT to get a MONDO power amp with highly sensitive speakers. 96db speakers never DID make any sense to me when run with 500 watt amps. Speaker is highly sensitive and you're running it at the WORST point in the THD / Power curve. www.stereophile.com/content/threshold-t-200-power-amplifier-measurements |
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Post by DavidR on Aug 12, 2018 21:49:13 GMT -5
First post BUT if it's that old it may nit have been kept up to date. Got it, we’ll that post is before my time, over 11 years old! 😮 Oh, well. Was just perusing the site for new (err old in this case) material to read.
Sorry and thanks for the input.
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Post by AudioHTIT on Aug 13, 2018 5:08:16 GMT -5
Got it, we’ll that post is before my time, over 11 years old! 😮 Oh, well. Was just perusing the site for new (err old in this case) material to read. Sorry and thanks for the input.
This post has an updated spreadsheet version of the original document, though it’s still old. emotivalounge.proboards.com/post/454252 |
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Post by DavidR on Aug 13, 2018 9:08:39 GMT -5
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