Official Emotiva XPA-5 Owners Thread - Page 43 - AVS Forum
Forum Jump: 
 4Likes
Reply
 
Thread Tools
post #1261 of 2048 Old 05-06-2013, 06:42 AM
AVS Special Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 6,084
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 261
Apparently my post was deleted in the clean-up. I did not think it all that bad but whatever...

Class A = 25% max theoretical efficiency for a single-ended circuit, 50% for push-pull (which is most audio amplifiers). Aside from getting an EE degree there are numerous on-line tutorials on amplifers and their efficiency.

Class A does not automatically provide the lowest distortion; many factors (including amplifier biasing) influence distortion. Most of the class A amplifiers that rotated through my system actually had higher distortion ratings than comparable (in power) AB amps, probably due to lower feedback. Since the speakers dominate the distortion it doesn't matter if it is 0.1%, 0.001 %, or whatever...

Also read Geigar's post as he has summarized quite nicely.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
Sponsored Links
Advertisement
 
post #1262 of 2048 Old 05-06-2013, 07:43 PM
Advanced Member
 
bo130's Avatar
 
Join Date: Sep 2009
Posts: 521
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 71
Quote:
Originally Posted by deltadube View Post

how would you know..

Okay - lets step back for a moment and let me quote what Bill wrote;
Quote:
"You are quite wrong in your assumption. So you have actual hands on experience with the Boston Acoustics A7200 amp? You have no idea what volume levels I listen to, how difficult my speakers are to drive or the size of my room. I have to laugh at this type of post from someone that apparently has no idea what they are talking about. I would seriously consider educating yourself further before discussing this subject further"

(bold is my emphasis)

So what do I know? I know exactly what Bill wrote above, and everything he typed there (particularly the bold) in response to you is correct - understand?

Good! biggrin.gif
bo130 is online now  
post #1263 of 2048 Old 05-07-2013, 12:00 AM
 
GIEGAR's Avatar
 
Join Date: Jan 2013
Location: Australia
Posts: 1,180
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Liked: 322
Quote:
Originally Posted by Bill Mac View Post

GIEGAR,

^^^^ Excellent post smile.gif. Especially this "They've spent $1400 on amps, they're excited, and like you (just above) had almost certainly made up their minds already... and their brains are telling them exactly what they want to hear. I don't doubt these owners are genuine in describing their experience, but what they've experienced actually has nothing to do the "sound quality" of the new amp".

I also agree that when listening to music it can sound better if I'm relaxed and in a good mood. If I'm distracted by whatever and I'm not focused on the music to enjoy it the music doesn't sound as good.

Bill
Thanks for the complement Bill. It's the first one I've received actually, so it's encouraging to learn that once in a while a post strikes a positive chord with a fellow member. smile.gif

Quote:
Originally Posted by Bill Mac View Post

GIEGAR,

Thanks for the kind words smile.gif. I'm definitely saving my back for more enjoyable activities than hauling amps around. The Sherbourn 72100A (120 lbs.) was the last straw for me eek.gif! I just hope that my experiences will help others as it has helped me. I would say we have similar opinions on this hobby (obsession wink.gif) of ours. I really think that common sense has to come into play sooner or later.

Bill
Hopefully sooner, but as a relative newcomer to the hobby and AVS, I'm actually enjoying the challange at the moment.
GIEGAR is offline  
post #1264 of 2048 Old 05-07-2013, 05:41 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by deltadube View Post

 
well the question was directed at K...

you jumped in ...

i guess your the one poking fun eh!!!!!!!

but if you really think A class amps are the same in theory as AB class amps your theory is all wrong eh.. ab is half a sine wave versu the full sine wave of A... im no expert but a full wave is better
than a 1/2 wave eh... LOL...

maybe you just wanted to chop me down... but i got da power... of my xpa 3.. looking to upgrade now for sure.. need more power... full sine wave power eh..

the reviews of people with the amps point to better sound quality!!!

cheers..

 

Directed to me?  OK, well I have been away for a few days so I missed it unfortunately. Nonetheless, I have little to add to Arny's reply - if you can point us to some reasoned discussion on why a 31k amp gives better SQ than a much cheaper one, and especially any info where people can be seen to be able to actually hear a difference in a blind test, then I'll engage.

 

The reviews of "the people with the amps" are, unfortunately, sighted reviews and therefore have no real relevance to any objective assessment. They are just 'opinion' and as such are no more valid that anyone else's opinion that "there is no difference". What we need is some objective assessment of the performance of the amps in question, with all possibility of bias removed. Then, if there is an audible difference, and it is reliably heard, we will be on to something. In the meantime, and in the absence of any further information, all we can do is base our views on the results of the many blind ABX tests that have been performed over many years, all of which come to the conclusion that people cannot hear these alleged sonic differences you describe.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1265 of 2048 Old 05-07-2013, 05:47 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by Bill Mac View Post

I have to give credit to the very knowledgable members in this thread that have been trying so hard to help another not so well informed member smile.gif. You have all given examples backed by much experience and science as well. At one time I was under the impression that the more power the better. But many here much more knowledagable than I ever will be taught me different. I was on the "amp a month club" chasing the holy grail of amps. What I found was I did not need even 200 wpc in my small room. I have had the same Boston Acoustics A7200 amp in my system for quite awhile now. I see no need to change amps as the A7200's conservatively rated 100 wpc is more than I will ever need. So I would like to thank all those that have helped me get off the endless merry-go-round of amp change outs. I know my back appreciates it wink.gif.

Bill

 

Hey Bill - the voice of reason! :)  Yes, isn't it amazing how, when one actually understands what amps do and what they contribute to the overall SQ, the endless merry-go-round suddenly stops!  I have had the same amp in my music system for decades now and have had my Emotiva amps in my HT system for a few years and have absolutely no need to, nor intention, of replacing them.  I have all da power that I need for loud, clean, unclipped, dynamic, unstressed performance, and then some, and any of da power that is left on the table is, of course, pointless.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1266 of 2048 Old 05-07-2013, 05:52 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by deltadube View Post

Quote:
Originally Posted by Bill Mac View Post

I have to give credit to the very knowledgable members in this thread that have been trying so hard to help another not so well informed member smile.gif. You have all given examples backed by much experience and science as well. At one time I was under the impression that the more power the better. But many here much more knowledagable than I ever will be taught me different. I was on the "amp a month club" chasing the holy grail of amps. What I found was I did not need even 200 wpc in my small room. I have had the same Boston Acoustics A7200 amp in my system for quite awhile now. I see no need to change amps as the A7200's conservatively rated 100 wpc is more than I will ever need. So I would like to thank all those that have helped me get off the endless merry-go-round of amp change outs. I know my back appreciates it wink.gif.

Bill

well i guess you dont turn up the volume Bill...

cheers..
 
If you made the same guess about me (and I agree 100% with Bill's post), you'd be totally wrong. I watch all my movies at between -5ddB and -9dB from Reference, depending on the source content. This is giving me about 100dB on peaks typically, so there can be no suggestion I don't turn up the volume. I can hit Reference with no problems too, but it is simply too loud, other than for short demos.  This is from an XPA-3 and two UPA-2s.
 
There's no logic at all to what you keep saying - you contradict yourself quite often too. Truth is you need the power you need to hit the levels you require, cleanly. Any more is wasted.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1267 of 2048 Old 05-07-2013, 05:56 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by DonH50 View Post

Class-A push-pull amplifiers are at most 50% efficient, meaning a 35-W Class-A bias level is dissipating more than 70 W constantly, plus losses, plus driver stages and all the other circuits. Probably ~100 W. Ever put your hand on a 100 W light bulb? smile.gif
 

 

Hey Don... I can certainly confirm that. My 50 wpc x 2 Class A stereo amp (now well over 20 years old) has heatsinks bigger than the rest of the amp and they get way too hot to touch safely. All that energy has to go somewhere...



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1268 of 2048 Old 05-07-2013, 06:10 AM
AVS Addicted Member
 
Bill Mac's Avatar
 
Join Date: Nov 2003
Posts: 11,499
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 106 Post(s)
Liked: 451
Quote:
Originally Posted by kbarnes701 View Post

Hey Bill - the voice of reason! smile.gif  Yes, isn't it amazing how, when one actually understands what amps do and what they contribute to the overall SQ, the endless merry-go-round suddenly stops!  I have had the same amp in my music system for decades now and have had my Emotiva amps in my HT system for a few years and have absolutely no need to, nor intention, of replacing them.  I have all da power that I need for loud, clean, unclipped, dynamic, unstressed performance, and then some, and any of da power that is left on the table is, of course, pointless.

Hey Keith,

Good to have you back smile.gif. To be honest the deep technical aspects of amps escape me redface.gif. But thanks to the many here including yourself I was able to learn that the SQ differences "I thought I was hearing" were not actually there. So once I removed the "new amp bias expectation" I found that I could in all honestly not hear the "day and night" differences I thought I was hearing wink.gif.

Bill


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
, watch it grow and my wallet shrink ;-).

 

Denon 4311 (in preamp mode), Parasound 2100, Boston Acoustics A7200 amp, Oppo BDP-103, Consonance CD120, Panasonic TC-P60GT50 plasma, Panamax 5100EX, Salk Song Towers, Song Center, ADS 300C (surrounds) and two Rythmik F12SEs.
Bill Mac is offline  
post #1269 of 2048 Old 05-07-2013, 06:54 AM
 
GIEGAR's Avatar
 
Join Date: Jan 2013
Location: Australia
Posts: 1,180
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 41 Post(s)
Liked: 322
Milt99: Caught your short lived post earlier today in which you took umbrage to this part of my post #1257:

Quote:
I'm not surprised. As I said previously, they've just done sighted, non level matched informal listening sessions. They've spent $1400 on amps, they're excited, and like you (just above) had almost certainly made up their minds already... and their brains are telling them exactly what they want to hear. I don't doubt these owners are genuine in describing their experience, but what they've experienced actually has nothing to do the "sound quality" of the new amp. Have you ever noticed how much more you enjoy music when you're already in a great mood? Are your favourite songs the ones that bring back memories of great experiences? These are other examples of the power of the human brain.

Happy to respond if you wish to post again in a manner that will survive. You know what I mean. wink.gif
GIEGAR is offline  
post #1270 of 2048 Old 05-07-2013, 08:05 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by Bill Mac View Post

Quote:
Originally Posted by kbarnes701 View Post

Hey Bill - the voice of reason! smile.gif  Yes, isn't it amazing how, when one actually understands what amps do and what they contribute to the overall SQ, the endless merry-go-round suddenly stops!  I have had the same amp in my music system for decades now and have had my Emotiva amps in my HT system for a few years and have absolutely no need to, nor intention, of replacing them.  I have all da power that I need for loud, clean, unclipped, dynamic, unstressed performance, and then some, and any of da power that is left on the table is, of course, pointless.

Hey Keith,

Good to have you back smile.gif. To be honest the deep technical aspects of amps escape me redface.gif. But thanks to the many here including yourself I was able to learn that the SQ differences "I thought I was hearing" were not actually there. So once I removed the "new amp bias expectation" I found that I could in all honestly not hear the "day and night" differences I thought I was hearing wink.gif.

Bill

 

I think the most important part of the discussion did certainly not escape you, Bill - and that is that the amp makes the least significant contribution of all, when compared with that made by speakers, speaker placement and the room itself, including treatments and/or Room EQ. The difference between you and so many others is that you were prepared to approach this objectively, with a view to learning more, and that approach has paid off for you, big time.  As has been said many times, it's their own money and they can spend it however they choose. The issue I have is when they state as 'fact' that amp A will 'blow away' Amp B in SQ, when Amp B is performing within its design criteria and not clipping. The good news for you and I is that we can spend the money we have saved on CDs, Blu-rays and so on and thus get even more enjoyment out of our systems.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1271 of 2048 Old 05-07-2013, 02:48 PM
AVS Special Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 6,084
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 261
Power is not the only parameter in amplifier design, and often it is among the least important although it drives many other parameters... Ditto THD.

In most systems the speakers dominate the distortion. A lot of folk would be shocked at high how the distortion is from our speakers at volumes well below reference levels.

The room usually dominates the frequency response.

All IMO/IME, of course, and that of various professors, texts/reference books, and other such sources. - Don

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
post #1272 of 2048 Old 05-07-2013, 08:39 PM
Member
 
crystalineblue's Avatar
 
Join Date: Mar 2013
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
hi fellow emotiva owners,

can anyone tell me the input sensitivity of xpa3 or xp5? I presume X series have the same input sensitivity. I cannot find it in our manual. My receiver's rated output is just 200mV with maximum at 4.6V at 470ohms.

Thanks.
crystalineblue is offline  
post #1273 of 2048 Old 05-07-2013, 09:24 PM
AVS Special Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 6,084
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 261
Gain is 32 dB so to reach 200 W (8 ohms) requires a hair over 1 V. This matches the level shown in the test report on the website. Your AVR's output will be plenty.

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
post #1274 of 2048 Old 05-07-2013, 09:59 PM
Member
 
crystalineblue's Avatar
 
Join Date: Mar 2013
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by DonH50 View Post

Gain is 32 dB so to reach 200 W (8 ohms) requires a hair over 1 V. This matches the level shown in the test report on the website. Your AVR's output will be plenty.


Thanks DonH50.
crystalineblue is offline  
post #1275 of 2048 Old 05-08-2013, 12:08 AM
Member
 
crystalineblue's Avatar
 
Join Date: Mar 2013
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by DonH50 View Post

Gain is 32 dB so to reach 200 W (8 ohms) requires a hair over 1 V. This matches the level shown in the test report on the website. Your AVR's output will be plenty.

Hi DonH50,

Read an article from audioholics about voltage computation. And if my computation is correct (am not an engineer nor an engineering student biggrin.gif), my AVR of 200mV and 4.6v max cannot drive my xpa3 to full power... that is 200 watts in 8ohms. Luckily, I guess (if my computation is correct), it can drive my xpa3 to 125watts in 6ohms easily. Based on my computation, my avr can only drive xpa3 to 146watts in 8 ohms max. I think its good enough for a 125watts 6ohms speaker.

your suggestions/clarfications is very much appreciated.

thanks.
crystalineblue is offline  
post #1276 of 2048 Old 05-08-2013, 02:50 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by crystalineblue View Post

Quote:
Originally Posted by DonH50 View Post

Gain is 32 dB so to reach 200 W (8 ohms) requires a hair over 1 V. This matches the level shown in the test report on the website. Your AVR's output will be plenty.

Hi DonH50,

Read an article from audioholics about voltage computation. And if my computation is correct (am not an engineer nor an engineering student biggrin.gif), my AVR of 200mV and 4.6v max cannot drive my xpa3 to full power... that is 200 watts in 8ohms. Luckily, I guess (if my computation is correct), it can drive my xpa3 to 125watts in 6ohms easily. Based on my computation, my avr can only drive xpa3 to 146watts in 8 ohms max. I think its good enough for a 125watts 6ohms speaker.

your suggestions/clarfications is very much appreciated.

thanks.

 

Which AVR do you have?



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1277 of 2048 Old 05-08-2013, 04:50 AM
AVS Addicted Member
 
Bill Mac's Avatar
 
Join Date: Nov 2003
Posts: 11,499
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 106 Post(s)
Liked: 451
Below is a link to a thread over at the Emotiva Lounge. The thread is discussing the addition of an XPA-5 to a Denon 4520. The interesting part of the discussion are the thoughts that with the addition of the XPA-5 that overall SQ is improved. In that certain aspects of music have better clarity and that the soundstage is improved. It has been a very civil and respectful exchange of differing opinions. My main question is that if the volume levels are matched between using the 4520's amp section and then with the addition of the XPA-5 how does the SQ improve with just the addition of the XPA-5. Also how can one really do an accurate comparison when it takes a fair amount of time to add the XPA-5 or remove it for the comparison. I also asked if these differences happened at low to moderate volume levels and several in the discussion said that they heard SQ improvement at these volume levels as well.

So I would like to ask those in this thread what could the XPA-5 be doing to the signal to improve SQ in both clarity of specific instruments and improve the soundstage? I'm under the assumption that an amp like the XPA-5 should be transparent and not add anything to the signal or alter the SQ of the music one is listening to. But maybe I'm wrong in that assumption. With that I would like to know what in fact an external amp such as the XPA-5 could be doing to improve upon the SQ of the amp section of the 4520. I also would have to believe that the amp section in the 4520 is quite good and not lacking unless driven really hard with challenging speakers. So any thoughts on this discussion would be appreciated smile.gif.

http://emotivalounge.proboards.com/index.cgi?board=amps&action=display&thread=30377


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
, watch it grow and my wallet shrink ;-).

 

Denon 4311 (in preamp mode), Parasound 2100, Boston Acoustics A7200 amp, Oppo BDP-103, Consonance CD120, Panasonic TC-P60GT50 plasma, Panamax 5100EX, Salk Song Towers, Song Center, ADS 300C (surrounds) and two Rythmik F12SEs.
Bill Mac is offline  
post #1278 of 2048 Old 05-08-2013, 05:58 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by Bill Mac View Post

Below is a link to a thread over at the Emotiva Lounge. The thread is discussing the addition of an XPA-5 to a Denon 4520. The interesting part of the discussion are the thoughts that with the addition of the XPA-5 that overall SQ is improved. In that certain aspects of music have better clarity and that the soundstage is improved. It has been a very civil and respectful exchange of differing opinions. My main question is that if the volume levels are matched between using the 4520's amp section and then with the addition of the XPA-5 how does the SQ improve with just the addition of the XPA-5. Also how can one really do an accurate comparison when it takes a fair amount of time to add the XPA-5 or remove it for the comparison. I also asked if these differences happened at low to moderate volume levels and several in the discussion said that they heard SQ improvement at these volume levels as well.

So I would like to ask those in this thread what could the XPA-5 be doing to the signal to improve SQ in both clarity of specific instruments and improve the soundstage? I'm under the assumption that an amp like the XPA-5 should be transparent and not add anything to the signal or alter the SQ of the music one is listening to. But maybe I'm wrong in that assumption. With that I would like to know what in fact an external amp such as the XPA-5 could be doing to improve upon the SQ of the amp section of the 4520. I also would have to believe that the amp section in the 4520 is quite good and not lacking unless driven really hard with challenging speakers. So any thoughts on this discussion would be appreciated smile.gif.

http://emotivalounge.proboards.com/index.cgi?board=amps&action=display&thread=30377

 

Hey Bill.

 

This sort of thing comes up all the time. Someone buys a new amp, adds it to their system and suddenly they hear 'night and day' differences. Typically, they hear things on their discs that they 'never heard before', 'improved clarity', 'better soundstage', 'better imaging' and so on. Often their wives/girlfriends hear the differences too ;)

 

The one thing that all of these reports have in common is that they are subjective. They are always sighted tests, always in uncontrolled conditions. In every branch of science where A is tested against B, (eg medicine) these conditions for testing would result in immediate dismissal and incredulity. Sighted tests mean that the well-proven phenomenon of expectation bias cannot be ruled out of any apparent 'result'. And of course when someone has laid down significant coin for a new amp, expectation is high. If the test was conducted blind, the question we need to ask is if the same differences could be heard?  The answer, in every properly conducted blind test that I have read about is that people cannot differentiate between any two modern SS amps that are not broken and are working within their design parameters. 

 

Another problem with the 'tests' of the type you report on is that it is also well known that volume levels need to be very precisely matched if the test result is to be valid. This is due to a well-proven and documented psychoacoustic phenomenon where 'louder' usually sounds 'better' to the listener, and indeed when the signal is louder, it may also be possible to hear some things that could not be heard when the signal was less loud. It is impossible for people at home, without suitable equipment, to accurately set the volume levels on each amp to +/- 0.5dB, so again their results have no real value.

 

A further complication in this sort of subjective evaluation is that the tests are usually conducted by swapping Amp A out with Amp B and then listening again. But for a test to be valid, the swap must be instantaneous, using some form of switching device. Otherwise, 'auditory memory' comes into play and, again, it had been well-established that human auditory memory lasts only a few seconds. As it is impossible to swap amps in that time, the test is again invalidated by proven scientific research. 

 

Finally, the conditions in which the 'tests' take place are not controlled in any way. In addition to the points raised above, people will often move speakers, change other components at the same time, listen days apart, use random audio tracks for testing, not necessarily the same on each item under test and so on. Given all of this, it is likely that their 'tests' will indeed show variations in SQ - but these variations are not a result of the difference between Amp A and Amp B.

 

There are very good reasons that, in other fields of science, tests are done in controlled conditions, following well-researched and understood protocols. In medicine, for example, when Drug A is tested against Drug B or a placebo, the trials are always blind (usually double blind). The idea of telling the patient which drug he was taking is laughable. 

 

Coming to the second part of your post - what can account for any differences in Amp A and Amp B that will deliver the differences alleged by the posters you reference?

 

If both amps are not broken and both are working within their design parameters, and not clipping, then the answer is nothing. In every properly conducted blind test that I have seen, the results are always the same: people cannot differentiate between the two amps under test with any reliability more than pure random chance. Often they 'hear' differences between amps when it is the same amp that has been 'switched to'!

 

If you look at the specs of modern SS amplifiers of the type we are discussing, you will see that in all cases they all have levels of distortion well below the threshold of human audibility. IOW, they take the input signal and output it in identical form, but louder. It follows therefore that if all amps take the input and output the same thing, but louder, there can be no audible differences between Amp A and Amp B.

 

So when could an amp make an audible difference?  Well, if Amp A is underpowered for the speakers it is driving and incapable of driving them cleanly to the desired SPLs, then replacing it with a more powerful amp will solve the clipping issues and it will therefore potentially sound better than the original amp. Hence my qualification above where I say that the amps must be not broken and working within their design parameters. It is also possible that a certain speaker presents a very difficult load to an amp and if the replacement amp has better capabilities with low impedance loads, then again there could be a noticeable difference.  HST, you are specifically referencing the amps in a Denon 4520 and an Emotiva XPA-5 and none of this is likely to apply to those two units, both of which will drive most speakers to very high SPLs without clipping. Bottom line: if the amp can drive the speakers you own to the levels you require and do so cleanly and without clipping, then swapping for another amp that can do the same will yield no sonic differences. 

 

If the XPA-5 and Denon 4530 were tested A-B or ABX in a properly conducted blind test, I would eat my hat without ketchup if a reliable difference in SQ could be identified between the two, given the caveats I mention above. So, unfortunately, the guys in the other thread are indeed 'hearing differences' - but they are perceived and not real, the result of improper testing procedures (eg no level matching) or expectation bias (as would be expected in a sighted test). IOW, their results have no real value to anyone else.

 

Oh yes, one final thing - if they are claiming that their new amp has improved soundstage, then that is usually a good clue that they are 'hearing things'. Amps don't impact on soundstage - that is a function of the speakers and their placement in the room. 

 

Disclaimer: if anyone wants to get into a never-ending discussion about the validity of ABX tests etc, saying that the tests themselves are not valid rather than the results derived from them, then pelase know that I will not respond nor be drawn into that discussion. It is a waste of everyone's time - the 'believers' will not change their mind no matter what the scientific evidence is that is presented. There are numerous other threads here on AVS devoted specifically to that sort of discussion and it seems to me to serve no purpose to derail this XPA-5 thread with all that.

BarracudaDelGato likes this.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1279 of 2048 Old 05-08-2013, 06:18 AM
AVS Addicted Member
 
Bill Mac's Avatar
 
Join Date: Nov 2003
Posts: 11,499
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 106 Post(s)
Liked: 451
^^^ Keith,

Thank you for your detailed and insightful post smile.gif. I have to agree with your thoughts. In the thread over at the Lounge I will not dispute what some are hearing. But the basis for those thoughts as you point out can be skewed by the fact that they are sighted listening comparisons. The other factor is that they are not direct A-B comparisons with significant time (5-10 minutes minimum I would think) for the amp to be added or removed. I also agree that the slightest difference in volume can effect the comparison as well.

I found this post (#86) from the previously linked thread to be very insightful and agree totally with the member who made the post. I hope he does not mind that I post his thoughts here, if he does I will delete it.

Regarding the wah-wah pedal in the track from Santana III: Was it that your old equipment didn't reproduce the wah-wah pedal, or was it that you just didn't notice it? I would wonder what would happen if you put your old equipment back in and then listened to the track to see how much different it really sounded.

I have had the experience of noticing something on a song that I never noticed before, but that could very well be that I just wasn't previously paying attention to that aspect. When we get new gear, I think we tend to listen more carefully and critically and thus may notice something now that was there before but we just didn't notice it back then. I'm not doubting what you say; I'm saying perhaps there is another explanation rather than the equipment. Something in the chain would have to be pretty poor in order not to reproduce a wah-wah pedal effect.


Bill


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
, watch it grow and my wallet shrink ;-).

 

Denon 4311 (in preamp mode), Parasound 2100, Boston Acoustics A7200 amp, Oppo BDP-103, Consonance CD120, Panasonic TC-P60GT50 plasma, Panamax 5100EX, Salk Song Towers, Song Center, ADS 300C (surrounds) and two Rythmik F12SEs.
Bill Mac is offline  
post #1280 of 2048 Old 05-08-2013, 06:34 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by Bill Mac View Post

^^^ Keith,

Thank you for your detailed and insightful post smile.gif. I have to agree with your thoughts. In the thread over at the Lounge I will not dispute what some are hearing. But the basis for those thoughts as you point out can be skewed by the fact that they are sighted listening comparisons. The other factor is that they are not direct A-B comparisons with significant time (5-10 minutes minimum I would think) for the amp to be added or removed. I also agree that the slightest difference in volume can effect the comparison as well.

I found this post (#86) from the previously linked thread to be very insightful and agree totally with the member who made the post. I hope he does not mind that I post his thoughts here, if he does I will delete it.

Regarding the wah-wah pedal in the track from Santana III: Was it that your old equipment didn't reproduce the wah-wah pedal, or was it that you just didn't notice it? I would wonder what would happen if you put your old equipment back in and then listened to the track to see how much different it really sounded.

I have had the experience of noticing something on a song that I never noticed before, but that could very well be that I just wasn't previously paying attention to that aspect. When we get new gear, I think we tend to listen more carefully and critically and thus may notice something now that was there before but we just didn't notice it back then. I'm not doubting what you say; I'm saying perhaps there is another explanation rather than the equipment. Something in the chain would have to be pretty poor in order not to reproduce a wah-wah pedal effect.


Bill

 

That quote is spot on IMO. I often hear things I have never heard before, even on content I am very familiar with. And this is without changing the gear at all!  'Hearing something I think I never heard before, and even having my wife hear it' is no reliable guide to what is going on. That's why the proper tests were invented. 

 

Stay true to the science, Bill - and spend your cash on either the things that really do make a difference to SQ (room and speakers) or on music and movies!  You shouldn’t need a new amp, ever, now you have a good one like yours is. I dont expect to buy a new amp in my lifetime really.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1281 of 2048 Old 05-08-2013, 08:21 AM
 
runnin''s Avatar
 
Join Date: Jan 2009
Posts: 1,557
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 42
* For those who believe they can hear a difference between the amp section of an AVR and a separate amp, let me suggest one of the many fine forums where such discussion is not frowned upon or censored. My current fave is Audiokarma.
runnin' is offline  
post #1282 of 2048 Old 05-08-2013, 09:38 AM
Advanced Member
 
Elmo C's Avatar
 
Join Date: Aug 2003
Posts: 618
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 16
Do they have any scientist over there? Music sounds better with the science to back it up...
Elmo C is offline  
post #1283 of 2048 Old 05-08-2013, 10:25 AM
 
runnin''s Avatar
 
Join Date: Jan 2009
Posts: 1,557
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 42
Music sounds best when a scientist is telling you so? I do not concur.
runnin' is offline  
post #1284 of 2048 Old 05-08-2013, 10:51 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667

Quote:

Originally Posted by Elmo C View Post

Do they have any scientist over there? Music sounds better with the science to back it up...
 

 

Quote:

Originally Posted by runnin' View Post

Music sounds best when a scientist is telling you so? I do not concur.

 

Of course not. Nobody is saying that. Reproduced music sounds best when you use good speakers, properly placed, in an acoustically treated room. The choice of amp (eg Denon 4520 or XPA-5) rarely has anything at all to do with it these days, that's all. Anyone using a system in an untreated room and sweating about his choice of amp is totally failing to understand even the most basic aspects of acoustic science. 

 

Worrying over minuscule levels of distortion produced by decent modern SS amps (which is always below the threshold of human audibility anyway) is pointless when also ignoring the distortions in the order of tens of magnitudes greater that is produced by the speakers/room. 

 

Anyone looking to improve the sound in his room needs to be looking at speakers, placing them properly and treating the room they are in. That is where the big differences come from - not from amps. Everyone who has actually tried this will tell you the same.



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1285 of 2048 Old 05-08-2013, 10:53 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by runnin' View Post

* For those who believe they can hear a difference between the amp section of an AVR and a separate amp, let me suggest one of the many fine forums where such discussion is not frowned upon or censored. My current fave is Audiokarma.

 


Got a link to some of their relevant threads?  I’d like to have a look.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1286 of 2048 Old 05-08-2013, 11:40 AM
AVS Special Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 6,084
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 261
Quote:
Originally Posted by crystalineblue View Post

Quote:
Originally Posted by DonH50 View Post

Gain is 32 dB so to reach 200 W (8 ohms) requires a hair over 1 V. This matches the level shown in the test report on the website. Your AVR's output will be plenty.

Hi DonH50,

Read an article from audioholics about voltage computation. And if my computation is correct (am not an engineer nor an engineering student biggrin.gif), my AVR of 200mV and 4.6v max cannot drive my xpa3 to full power... that is 200 watts in 8ohms. Luckily, I guess (if my computation is correct), it can drive my xpa3 to 125watts in 6ohms easily. Based on my computation, my avr can only drive xpa3 to 146watts in 8 ohms max. I think its good enough for a 125watts 6ohms speaker.

your suggestions/clarfications is very much appreciated.

thanks.

Your math is off. smile.gif

The XPA-3 only needs about 1 Vrms to drive to full power into 8 ohms, and your AVR's max output is 4.6 V per your post, so you have plenty of headroom.

200 W into 8 ohms is sqrt(8 ohms * 200 W) = 40 Vrms (power is voltage squared divided by resistance, P = V^2 / R, so V = sqrt(P * R) solving for voltage)

The amplifier's gain is 32 dB from the data sheet, and since we are talking voltage gain G = 20 * log (Vout / Vin). Plugging in 40 V and solving for Vin, we find Vin = 1.005 V to produce 200 W at the output. Most amplifiers look like voltage sources, so ideally would simply ratio power as the impedance drops as the voltage would remain the same (e.g. the amp would put out the same voltage and thus twice the power into an 4-ohm load). 40 Vrms into 6 ohms is thus 200 * 8/6 = 267 W if the amp is not current-limited. They spec 300 W into 4 ohms so you'd get your 267 W

If you go to the Emotiva site there are test results posted for the XPA-3 showing full power is reached with 1.050 V.

HTH - Don

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
post #1287 of 2048 Old 05-08-2013, 05:25 PM
Member
 
crystalineblue's Avatar
 
Join Date: Mar 2013
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by kbarnes701 View Post

Which AVR do you have?

Hi,

I have onkyo 818. smile.gif
crystalineblue is offline  
post #1288 of 2048 Old 05-08-2013, 05:30 PM
Member
 
crystalineblue's Avatar
 
Join Date: Mar 2013
Posts: 37
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by DonH50 View Post

Your math is off. smile.gif

The XPA-3 only needs about 1 Vrms to drive to full power into 8 ohms, and your AVR's max output is 4.6 V per your post, so you have plenty of headroom.

200 W into 8 ohms is sqrt(8 ohms * 200 W) = 40 Vrms (power is voltage squared divided by resistance, P = V^2 / R, so V = sqrt(P * R) solving for voltage)

The amplifier's gain is 32 dB from the data sheet, and since we are talking voltage gain G = 20 * log (Vout / Vin). Plugging in 40 V and solving for Vin, we find Vin = 1.005 V to produce 200 W at the output. Most amplifiers look like voltage sources, so ideally would simply ratio power as the impedance drops as the voltage would remain the same (e.g. the amp would put out the same voltage and thus twice the power into an 4-ohm load). 40 Vrms into 6 ohms is thus 200 * 8/6 = 267 W if the amp is not current-limited. They spec 300 W into 4 ohms so you'd get your 267 W

If you go to the Emotiva site there are test results posted for the XPA-3 showing full power is reached with 1.050 V.

HTH - Don

Hi Don,

My math is very rusty. I am only right with 40vrms, biggrin.gif
I'll try to catch up with your computation by comparing with audioholics and check where I got lost in translation. smile.gif

thanks.
crystalineblue is offline  
post #1289 of 2048 Old 05-09-2013, 03:04 AM
AVS Addicted Member
 
kbarnes701's Avatar
 
Join Date: Jan 2008
Location: Main Listening Positon
Posts: 17,795
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1344 Post(s)
Liked: 1667
Quote:
Originally Posted by crystalineblue View Post

Quote:
Originally Posted by kbarnes701 View Post

Which AVR do you have?

Hi,

I have onkyo 818. smile.gif

 

OK - well Don has answered the question like a Math God now anyway :)  The reason I asked is that I figured your answer would show that you are good to go with your chosen AVR and the XPA-3, as indeed you are. You will have no problem using the 818 with the XPA-3 - as Don says, your 818 will drive the XPA-3 to its max rated power, as I suspected. Enjoy!



To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
kbarnes701 is offline  
post #1290 of 2048 Old 05-09-2013, 07:55 AM
AVS Special Member
 
DonH50's Avatar
 
Join Date: Feb 2010
Location: Monument CO
Posts: 6,084
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 159 Post(s)
Liked: 261
Thanks kbarnes, but hardly that, just EE 101. Gobs of folk on AVS could do the same and plenty more; acoustics is more a hobby with me (decades since my grad acoustics classes).

Raining here today, much needed but a bit unusual, minds me of your side of the pond. smile.gif

"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley
DonH50 is offline  
Reply Receivers, Amps, and Processors

Tags
Emotiva Xpa 5 5 Channel Power Amplifier

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off