Can amplifier speed and resolution be measured?

[restorer-john]

How often is slew rate measured when the amp is driving a difficult speaker load?

Amplifiers are traditionally tested into capacitive loads at 10KHz using a square wave at a low amplitude and observing the resultant waveform.

 

[DonH56]

Amplifiers are traditionally tested into capacitive loads at 10KHz using a square wave at a low amplitude and observing the resultant waveform.

Exactly. And before someone asks, at low amplitude because bandwidth is much greater, so more likely to show a stability issue. Plus a full-power 10 kHz square wave is rather unlikely to be found in the real world...

 

[sergeauckland]

Exactly. And before someone asks, at low amplitude because bandwidth is much greater, so more likely to show a stability issue. Plus a full-power 10 kHz square wave is rather unlikely to be found in the real world...

Emerson Lake & Palmer.........
S

 

[DonH56]

Emerson Lake & Palmer.........
S

One of my favorite groups, saw them live on their Works tour, even got front-row seats (working the venue, sound guy, got to touch the great Moog!) Probably partly why tinnitus is now a part of my life...

 

[Jimbob54]

One of my favorite groups, saw them live on their Works tour, even got front-row seats (working the venue, sound guy, got to touch the great Moog!) Probably partly why tinnitus is now a part of my life...

The Moog has since gone on record and said the touching was non-consensual. Its retained lawyers and has a publishing deal in the works.

 

[DonH56]

Since we're off-topic, I know Keith and Greg passed away a few years ago; is Carl still with us?

 

[Jimbob54]

Since we're off-topic, I know Keith and Greg passed away a few years ago; is Carl still with us?

Touch wood. 70

 

[preload]

I appreciate the robust discussion, but to answer the OP's original question:
YES, of course amplifier "speed" and "resolution" can be measured.
In fact, I'm surprised that nobody seems to know how, but I guess we're all here to learn.

Let's take the Parasound Halo JC-1 monoblock amplifier, for instance. According to Stereophile, this amplifier was noted to have excellent "transient speed," which allowed it to have "smoother, more refined sound."
This is what the amplifier looks like (see photo below). As you can see, it is resting on the floor. Using a precision instrument, I was able to measure this amplifier's speed. Out of respect for forum members who are in the U.S. vs. other parts of the world, I will report it in both metric and imperial units.

After taking a series of measurements using a radar gun, I was able to determine that this amplifier's speed was:
Metric: 0.0 kph
Imperial: 0.0 mph

Note: this was consistent with my unblinded observation that the amplifier was at rest.

Once finished with the speed measurements, I proceeded to measure the amplifier's resolution.
But full disclosure: I did read the Stereophile article beforehand, where it was mentioned that the amplifier had phenomenal "resolution of low-level detail." I admit that this may have resulted in bias when I determined the unit's resolution. The measurement was also performed unblinded.

Using proprietary calculations that are built into the software code of Adobe Photoshop, I was able to determine that the resolution of the Parasound amplifier you see above was:
500 x 299 pixels

Now I realize that this post will be extremely controversial. I know that I should have measured before reading the Stereophile article, and I should have worn a blindfold while taking these speed and resolution measurements. However, in the name of science, I believe that my measurement technique can be replicated by anyone who chooses to, and this will let us average our results together.

Moving forward, I hope that we now know that, in fact, amplifier speed AND resolution are measurable properties.

 

[restorer-john]

Using proprietary calculations that are built into the software code of Adobe Photoshop, I was able to determine that the resolution of the Parasound amplifier you see above was:
500 x 299 pixels

Ah. The resolution is not the same as the size in pixels. According to my software, the resolution is 72 DPI.

 

[preload]

Ah. The resolution is not the same as the size in pixels. According to my software, the resolution is 72 DPI.

Behold! Not one, but TWO ways to measure amplifier resolution.

 

[andymok]

How about acceleration?

 

[Chrispy]

Or braking?

 

[Blumlein 88]

I've measured them breaking. Oh.............wait.....................................

 

[JSmith]

After taking a series of measurements using a radar gun, I was able to determine that this amplifier's speed was:
Metric: 0.0 kph
Imperial: 0.0 mph

I think you forgot the rotational and orbital speed of the Earth... oh and continental drift.

I always liked this;

There are certainly valid ways to increase sound quality; the electrical and acoustic principles at work here are well understood, and there are real engineers and scientists who work in this field. Noise can be reduced by improved filtering or gain staging; frequency response and distortion improved through the use of negative feedback in amplifiers; and so on. However, the major stumbling blocks are the recording quality and later compression and manipulation of the original signal itself, the cost of better parts, and just how much any change actually increases quality. Once a certain point is reached, further audible improvements become more to difficult to detect. The point of diminishing returns is rapidly reached. The technology available to make most components for playback is said to be sonically transparent. In such, to human hearing, we hear exactly what is on the recorded medium, with nothing added or taken away.

https://rationalwiki.org/wiki/Audio_woo#The_science



JSmith

 

[Asylum Seeker]

Speed and resolution, like pace and timing or musicality are meaningless words used by sloppy subjective reviewers.

...

Yeap, that pretty much describes the moderator of the NoBSBudgetAudio group on FB

 

[Wes]

I suspect a lot of what is thought of as speed in a modern amp is really the ability to drive that speaker (motor).

 

[egellings]

Why would you need speed to reproduce something as slow-moving as just the bass component?

 

[mhardy6647]

Why would you need speed to reproduce something as slow-moving as just the bass component?

Teh speed of sound is (still) independent of frequency.

 

[tomchr]

Yeah, but the speed at which the speaker cone moves is not. The amp drives the speaker, no?

Tom

 

[JSmith]

What is very much related here is the power supply, type used, implementation and amp circuit design/type/class;

https://www.electronicdesign.com/te...measuring-powersupply-transient-recovery-time



JSmith