Can you hear a difference in Sound between Audio Amplifiers?

[AcuDefTechGuy]

It's an easily provable point that audio systems sound better in a very quiet environment than a noisier one. That's why I prefer to listen late in the evening or very early in the morning. Sometimes I get up at 4:30am and listen.

Wow, 4:30 a.m?

I'm still in R.E.M. around that time.

I don't really have a set time. Just whenever I'm in a happy mood and not busy is a good time for me.

 

[cpp]

I don't really have a set time. Just whenever I'm in a happy mood and not busy is a good time for me.

That's pretty much the same for me as it takes a good mood to set back and compare amps while listening to the sounds, the music, the speakers and the waves lapping on the shoreline as I in most cases fall into R.E.M. when some soft jazz in playing.

 

[mtrycrafts]

There are many different frequency response parameters, like into different power levels or into different loads, or even with different input loads. Frequency response curves are also measured by doing a spectrum sweep, which is one frequency at a time. Amplifier performance gets a lot more interesting with complex input loads. These days I expect any well-designed amplifier, tube or solid state, to have a flat 1W frequency response curve into 8 ohm loads. Since they're all pretty much the same these curves are not very telling at all.

Delayed response:
I contacted a reliable source on this. In essence I am told that FR will be flat from 1 watt to rated power into the same load like 8 Ohms. At lower loads it will have a slight decrease at the top end. Since he tests gear frequently over the years I have no reason to doubt his input to me on this.

 

[mtrycrafts]

..
The Power Cube tells us how much voltage an amplifier can deliver into a variety of loads, yes; however, it only does so using 1kHz bursts.

And, I would think that just as measuring full power at 1kHz and at 20hZ-20kHz will drop about 10%-15% power so would that voltage. But, that is a tough test on the amp as it doesn't see full bandwidth at all times, no?

 

[Steve81]

At lower loads it will have a slight decrease at the top end.

Here's an interesting one:
Pioneer SC-57 9.1 A/V Receiver - Secrets of Home Theater and High Fidelity

Frequency response showed difference values, based on the load the amplifier encountered. With an 8 ohm load, we had a ride of 0.7 dB from 20 Hz to 20 kHz, but with 4 ohm loads we had a fall of just over 1.0 dB across the same range. A bit peculiar, but those were the bench results.

 

[Steve81]

But, that is a tough test on the amp as it doesn't see full bandwidth at all times, no?

Not sure what you mean here; no, we're generally not playing white noise on our systems, but we're not listening to 1kHz sine tones either. In any event, yes these types of tests are tough; more than one amp has died at the hands of the power cube.

 

[Irvrobinson]

Delayed response:
I contacted a reliable source on this. In essence I am told that FR will be flat from 1 watt to rated power into the same load like 8 Ohms. At lower loads it will have a slight decrease at the top end. Since he tests gear frequently over the years I have no reason to doubt his input to me on this.

It's not just lower loads or different phase angles or whatever, it is what happens to the amp's frequency response linearity as it is reproducing a complex set of signals into differing loads. I'm sure you'll agree, few of us listen to test tones. Static frequency response tests based on sweeps tell you something, but not everything.

 

[mtrycrafts]

.... I'm sure you'll agree, few of us listen to test tones. ....

Well, I am forced to agree here with one caveat, when setting up the system, level matching and EQ if needed.

 

[mtrycrafts]

Here's an interesting one:
Pioneer SC-57 9.1 A/V Receiver - Secrets of Home Theater and High Fidelity

I wonder how that FR would change with just a change in power output and not load differences.
Or, would that .3 dB or so make an audible difference with music source?

 

[Steve81]

I wonder how that FR would change with just a change in power output and not load differences.
Or, would that .3 dB or so make an audible difference with music source?

Read again; it's about a 2dB difference.

 

[mtrycrafts]

Read again; it's about a 2dB difference.

I thought I did
With an 8 ohm load, we had a ride of 0.7 dB from 20 Hz to 20 kHz, but with 4 ohm loads we had a fall of just over 1.0 dB across the same range. A bit peculiar, but those were the bench results.

 

[Steve81]

I thought I did

Get it now?

Into an 8 ohm load, the receiver in question had an upward tilting FR, rising by 0.7dB at 20kHz; into a 4 ohm load, that reversed, with a downward tilt of a little over a dB for a total difference of a bit over 1.7dB at 20kHz.

 

[STRONGBADF1]

It's an easily provable point that audio systems sound better in a very quiet environment than a noisier one. That's why I prefer to listen late in the evening or very early in the morning. Sometimes I get up at 4:30am and listen.

You've got the sickness really bad!

 

[mtrycrafts]

Get it now?

Into an 8 ohm load, the receiver in question had an upward tilting FR, rising by 0.7dB at 20kHz; into a 4 ohm load, that reversed, with a downward tilt of a little over a dB for a total difference of a bit over 1.7dB at 20kHz.

Yes, thanks, now I see it.

 

[Irvrobinson]

You've got the sickness really bad!

You have no idea...

 

[DD66000]

Poppycock!!!

What you've done is altered the electrical properties of croossover shifting its frequency response up or down not to mention the possibilities of adding unwanted anomalies such as increased phase angle. Dynamics is a term used to describe the output of an amplifier, not a speaker. Speakers use the term linearity.

There is NOTHING added that was unwanted. And any phase shift from the signal passing through the zero volt line is eliminated via the bias voltage.
They are some of the most natural sounding speakers you will ever hear. Musicians I know have told me they can't believe how real they sound compared to live music.

 

[Pyrrho]

Imagine most people saying "I have VERY good hearing, yet I can't make the difference between this 1k$ Denon/Emotiva and the 50 k$ Uberpriced amp"...

I have a friend who was a small time reviewer whom I tired to convince to do a blind test. His response, something to the effect: what will my readers say if I cannot hear a difference. Yep, that is the crux of the matter.

I think this pretty well sums up the situation for many reviewers. They dare not conduct such tests, because many of their readers will imagine that the reviewers have flawed hearing rather than showing that the two things really are audibly indistinguishable. Most people have a far greater interest in their livelihood and their reputations than they have in the truth.

Of course, many people who write reviews are not capable of competently performing a proper double blind test anyway, so they obviously will never do such tests.

 

[3db]

And you are side stepping the fact that what was in the '50s, '60s, '70s may not apply to today's technology. Look at capacitors, Polypropylene and Polystyrene produce slightly different sounds. Polystyrene caps, when used as by-pass caps in the HF circuit of a XO produces a more open, airy sound. Whereas using Polypropylene by-pass caps produce more of a dynamic sound. And those caps did not exist 1/2 a century ago.

So far, all you have been able to do is throw out subject claims but have not backed up anything you said with any tangeable test data or white papers to support your cause. Just sayin.

 

[3db]

I think this pretty well sums up the situation for many reviewers. They dare not conduct such tests, because many of their readers will imagine that the reviewers have flawed hearing rather than showing that the two things really are audibly indistinguishable. Most people have a far greater interest in their livelihood and their reputations than they have in the truth.

Of course, many people who write reviews are not capable of competently performing a proper double blind test anyway, so they obviously will never do such tests.

You pretty well summed up the whole audio review industry as a whole. There are exceptions of course....this site being one of the exceptions. Most reviewers don't back up their claims with factual data which renders the whole review nothing more than a personal opinion.

 

[panteragstk]

You pretty well summed up the whole audio review industry as a whole. There are exceptions of course....this site being one of the exceptions. Most reviewers don't back up their claims with factual data which renders the whole review nothing more than a personal opinion.

Which is why this is one of the very few sites I've read over the years. A press release is not a review. Too many seem to be exactly that.