Do all amplifiers sound the same thread

[3db]

I've opened this thread as not derail the thread that started this debate again.

This is issue is almost as contentious as the great cable debate of 1939 ..

Seriously, there has been much chatter about this between the two camps. However, the proponents that maintain amps sound different aren't willing to conduct blind tests (to eliminate sight bias) while the other camp cries foul on them.

I recognize the need for power that separates have to offer especially when driving demanding speakers in large rooms or at louder volume levels. The analogy of an underpowered engine trying to propel a heavy car can be applied here.

However, what if the load presented to the amp isn't overly demanding, the room isn't overly large and the volume kept at comfortably loud levels. If the receiver or amp are well within their power envelope and not anywhere near their limit, would there be a difference in sound?

I'm in the camp that says, there is no difference until one of the variables (isn't overly demanding, the room isn't overly large and the volume kept at comfortably loud levels) changes. The basis for my opinion is based on ruler flat frequency response beyond the audable spectrum.

Lets keep this discussion clean without throwing personall digs. Let the fun begin.

 

[Steve81]

I'm of the opinion that audible differences between amplifiers will be correlated with significant measurable differences. However, we're generally not getting a complete picture with the range of tests typically run (usually into an 8 ohm resistor), and worse we have no idea what kind of load many loudspeakers present. In this kind of climate, it's easy to see why an argument could arise. Add in psychological factors which will play havoc with how we interpret what we hear, and you've got a real ****storm.

 

[gene]

I've opened this thread as not derail the thread that started this debate again.

This is issue is almost as contentious as the great cable debate of 1939 ..

Seriously, there has been much chatter about this between the two camps. However, the proponents that maintain amps sound different aren't willing to conduct blind tests (to eliminate sight bias) while the other camp cries foul on them.

I recognize the need for power that separates have to offer especially when driving demanding speakers in large rooms or at louder volume levels. The analogy of an underpowered engine trying to propel a heavy car can be applied here.

However, what if the load presented to the amp isn't overly demanding, the room isn't overly large and the volume kept at comfortably loud levels. If the receiver or amp are well within their power envelope and not anywhere near their limit, would there be a difference in sound?

I'm in the camp that says, there is no difference until one of the variables (isn't overly demanding, the room isn't overly large and the volume kept at comfortably loud levels) changes. The basis for my opinion is based on ruler flat frequency response beyond the audable spectrum.

Lets keep this discussion clean without throwing personall digs. Let the fun begin.

Assuming a perfectly resistive speaker load, low noise, low output impedance and the amplifier can maintain sufficient output voltage without power supply lag, then its very conceivable the sonic differences between two amps will be indistinguishable. Lots and LOTS of caveats for this to be the case.

 

[3db]

I'm of the opinion that audible differences between amplifiers will be correlated with significant measurable differences. However, we're generally not getting a complete picture with the range of tests typically run (usually into an 8 ohm resistor), and worse we have no idea what kind of load many loudspeakers present. In this kind of climate, it's easy to see why an argument could arise. Add in psychological factors which will play havoc with how we interpret what we hear, and you've got a real ****storm.

I agree that amp testing the way is done currently doesn't represent anywhere near how an amplifiers behaves driving real loads. That is why I've listed the caveats about the load not being overly difficult to drive. Maybe I should further stipulate that phase angles are no higher then a 50 degrees degrees and the impedance doesn't dip below 4 ohms. I also want to eliminate the psychological factors with the blind test. I hope this thread doesn't turn into a sh?t storm.

 

[3db]

Assuming a perfectly resistive speaker load, low noise, low output impedance and the amplifier can maintain sufficient output voltage without power supply lag, then its very conceivable the sonic differences between two amps will be indistinguishable. Lots and LOTS of caveats for this to be the case.

Gene, I'm the first one to agree with you that speaker load will determine how an amp behaves. However, the Pioneers mentioned aren't a difficult load compared to many a speaker you have tested here. So if the load is fairly light, how can the added power of separates benefit the sound of the speaker if its not challenging the amp in the first place?

 

[gene]

Gene, I'm the first one to agree with you that speaker load will determine how an amp behaves. However, the Pioneers mentioned aren't a difficult load compared to many a speaker you have tested here. So if the load is fairly light, how can the added power of separates benefit the sound of the speaker if its not challenging the amp in the first place?

I haven't measured the impedance of the Pios yet but I suspect they aren't as easy of a load to drive as you may think. I noticed they do eat up a lot of power to play loudly. They will probably be driven just find with a good mid level A/V receiver but it's never a bad thing to have more power at hand, especially when driving a mult-channel system. Realize that small bookshelf speakers (surrounds) are usually very in-efficient so again more power is a good thing.

 

[Steve81]

That is why I've listed the caveats about the load not being overly difficult to drive. Maybe I should further stipulate that phase angles are no higher then a 50 degrees degrees and the impedance doesn't dip below 4 ohms. I also want to eliminate the psychological factors with the blind test.

I guess the question is, what do you hope to achieve?

I'm not disputing that two different amplifiers, say an XPA-2 and my Onkyo TX-SR707, could sound quite similar if not indistinguishable under the right circumstances (in fact, I've made such arguments myself). But if you're restricting the circumstances, then you're also restricting the real world utility of such a test.

 

[AcuDefTechGuy]

Why don't we take a poll on this?

If you can hear a difference between amps, that's great.

If you cannot hear a difference between amps, that's great too.

I do like properly conducted DBT in audio. I know it's not as rigorous and meaningful as drug testing on patients. But it does remove human bias. I think it is unfair comparing amps when people know exactly which amp costs $300 (like Pioneer AVR) and which amps cost $20,000 (like Boulder monoblocks).

Sure, some speakers are more difficult to drive, so there must be some exceptions too.

 

[adwilk]

I wanna play. This should be fun.

Here's my take... My knowledge of solid state amplifier operation is far from comprehensive, but what I do know leads me to believe that any number of amplifiers of similar architecture operating within their intended design parameters would be indistinguishable. I also think there is reasonable threshold beyond those limits where no audible differences could be heard.

 

[3db]

I haven't measured the impedance of the Pios yet but I suspect they aren't as easy of a load to drive as you may think. I noticed they do eat up a lot of power to play loudly. They will probably be driven just find with a good mid level A/V receiver but it's never a bad thing to have more power at hand, especially when driving a mult-channel system. Realize that small bookshelf speakers (surrounds) are usually very in-efficient so again more power is a good thing.

I guess the question is, what do you hope to achieve?

I'm not disputing that two different amplifiers, say an XPA-2 and my Onkyo TX-SR707, could sound quite similar if not indistinguishable under the right circumstances (in fact, I've made such arguments myself). But if you're restricting the circumstances, then you're also restricting the real world utility of such a test.

I'm trying to prevent the incorrect assertion of amps sound different" as a broad statement that fits all speakers and that people should upgrade their amplfication to improve upon the sound. My assertion is that amps will sound different only if their load is difficult to drive or the environment that the speakers are in or used for..large room/loud sound. I want to see qualifications behind statements to make it more accurate.

 

[gene]

Why don't we take a poll on this?

If you can hear a difference between amps, that's great.

If you cannot hear a difference between amps, that's great too.

I do like properly conducted DBT in audio. I know it's not as rigorous and meaningful as drug testing on patients. But it does remove human bias. I think it is unfair comparing amps when people know exactly which amp costs $300 (like Pioneer AVR) and which amps cost $20,000 (like Boulder monoblocks).

Sure, some speakers are more difficult to drive, so there must be some exceptions too.

Salk had a very cool switcher at our GTG event that allowed you to instantaneously switch out amps and speakers all level matched via remote. I need to get me one of those. No need for a Blind test as you can't determine which amp is playing like you could with speakers seeing the cones moving. It would be fun to instantly switch between amps.

I want to be able to test sonic differences between say an Emotiva XPR-2 and a Pass Labs X350.5.

 

[AcuDefTechGuy]

Salk had a very cool switcher at our GTG event that allowed you to instantaneously switch out amps and speakers all level matched via remote. I need to get me one of those. No need for a Blind test as you can't determine which amp is playing like you could with speakers seeing the cones moving. It would be fun to instantly switch between amps.

I want to be able to test sonic differences between say an Emotiva XPR-2 and a Pass Labs X350.5.

I don't think it has to be double-blinded; but a single-blinded test using that amp switcher would be cool. IOW, the person physically doing the switching knows which amp is which, but the person doing the listening/ comparing does not.

I don't think we should tell everyone, "Okay, this is the Pass Lab........this is the Emotiva........"

I think it should be, "This is amp#1.......this is amp#2......."

 

[3db]

I wanna play. This should be fun.

Here's my take... My knowledge of solid state amplifier operation is far from comprehensive, but what I do know leads me to believe that any number of amplifiers of similar architecture operating within their intended design parameters would be indistinguishable. I also think there is reasonable threshold beyond those limits where no audible differences could be heard.

Everyone is welcome. I think its a good fact finding thread as its intended to be.

 

[3db]

I don't think it has to be double-blinded; but a single-blinded test using that amp switcher would be cool. IOW, the person physically doing the switching knows which amp is which, but the person doing the listening/ comparing does not.

I don't think we should tell everyone, "Okay, this is the Pass Lab........this is the Emotiva........"

I think it should be, "This is amp#1.......this is amp#2......."

+1 .... That's how I would run it. The level match Salk device would make it so much easier.

 

[Steve81]

I'm trying to prevent the incorrect assertion of amps sound different" as a broad statement that fits all speakers and that people should upgrade their amplfication to improve upon the sound.

I'm not sure anyone here is trying to make a broad statement: it's always a case by case basis, ie picking the right tool for the job. It's like trying to say there's no difference between 16AWG wire and 12AWG wire...realistically it just depends.

 

[mtrycrafts]

I'm trying to prevent the incorrect assertion of amps sound different" ...

Just curious. Preven yourself or others?

Why don't we take a poll on this?

If you can hear a difference between amps, that's great.

If you cannot hear a difference between amps, that's great too.

Yes, but that is valid for singular realities only, no?

I do like properly conducted DBT in audio. I know it's not as rigorous and meaningful as drug testing on patients. But it does remove human bias. I think it is unfair comparing amps when people know exactly which amp costs $300 (like Pioneer AVR) and which amps cost $20,000 (like Boulder monoblocks).

Sure, some speakers are more difficult to drive, so there must be some exceptions too.

It is more than unfair, it has no meaning.

The exception is that one does not exceed design limits of an amp, period. Driving it into clipping is outside of the design, right?

Maybe Gene should also look into the device Dr. David Rich used to test amps for The Audio Critic what he called the Power Cube method or something. It measure amps into loads as low as 1 Ohm and + and - phase shifts to 60 degrees and showed a cube diagram of voltage sags. Such a cube may still be up on their web site, not sure. I remember even the Bryston 5 ch amp had problems with that test

 

[ski2xblack]

I posted this link in another thread. Seems appropriate here too.

 

[mtrycrafts]

Salk had a very cool switcher at our GTG event that allowed you to instantaneously switch out amps and speakers all level matched via remote. I need to get me one of those. No need for a Blind test as you can't determine which amp is playing like you could with speakers seeing the cones moving. It would be fun to instantly switch between amps.

I want to be able to test sonic differences between say an Emotiva XPR-2 and a Pass Labs X350.5.

Yes, but does that switcher keep an internal count of correct guesses???
Just declaring one is different is not enough unless you can do it consistently, even if no switching has taken place.

 

[AcuDefTechGuy]

If my cousin thinks his $50,000 tube amp sounds better with his Focal Grande Utopia III than some Emotiva or Crown amps, I'm not going to argue with him no matter what I think because it is not worth it.

And if someone thinks his Emotiva or Crown amps sound just as good as Pass Lab, Mark Levinson, Krell, etc, there's no harm in that as well.

 

[Steve81]

It is more than unfair, it has no meaning.

From a technical standpoint, this is true. From a real world standpoint, I think the implications are clear: you can't just write off human psychology. Pride of ownership matters quite a lot to most people.

One thing I found interesting was that before the (in)famous Stereo Review test, they let both the "skeptics" and the "believers" spend some time with the amplifiers they were going to blind test; during this session, it was noted that practically all the listeners, including the skeptics who should have (at least in theory) known better, felt they could hear differences.

http://webpages.charter.net/fryguy/Amp_Sound.pdf