Are class D amps tone affected by master volume level?

[Wicked G]

I own quite a few Class D amps and have owned many more and agree that any change in tone is more than likely just perceived. However I and other Orange Terror Bass owners have noticed that the louder the Terror Bass gets, the more it changes in tone. And I'm not talking about more low end, I'm talking about more mids coming through as though the amp is compressing the low end and allowing more mids to shine through like a tube amp would. Plus it behaves differently. Really cool what it does.

 

[hasbeen]

Yeah you need more bass and treble at lower volumes, thus the loudness control on home stereo amps (see Fletcher-Munson curves)

Thanks for that. That's exactly what I was referring to in my post.

 

[agedhorse]

Thanks everyone for the insight. It does seem to me like there is some difference when I turn the amp up during a show. Which after reading to all your replies, I now believe is probably the speakers themselves coming alive and getting fuller, maybe some additional room reinforcement added in.
The music I'm playing is Americana, so other than compressor (which I have and will start using), I'm not sure what in the way of other pedals might be genre appropriate.

Our perception of sound is affected by its volume. Part of this is the Fletcher-Munson curve, part of it is the phenomenon of perceiving more detail in louder sounds. So you might hear your playing differently at different volumes, even though the preamp is working exactly the same way in all cases and the power section is not meaningfully changing the tone as you change the master volume.

I definitely hear more low end at higher volume.

It's not the amp or speakers as much as it is your ears and the human perception of hearing versus frequency. This is very much built into some lower powered amps amps to compensate for low volume applications.

Class D doesn't overdrive as class A /AB does. It's perfectly clean, the input is (typically) compared against a sawtooth oscillator to generate the pulse width modulated RADIO frequency the amplifier amplifies. It's a mathematical process, it's internally limited, if not it would give the same result as overdriving an A/D recording interface: random noise. There's no clipping level at which the output saturates and generates all the harmonics.

This is simply not true, the entire (end to end) process is adapted to allow for clipping or overdriven operation via a number of management methods. It's not a digital process like an A/D, there is no numerical representation of the value at any given point, when the PWM process runs out of duty cycle the output remains at that value and the demodulate result is a clipped signal (provided the feedback loop remains stable and compensated). There is no random noise.

 

[LiptonJigglers]

It's been my experience, with any class of amp I've used, that my sound improves when the master volume is turned up. The only exception is when I'm considerably underpowered for the job at hand. That's when turning up creates more problems than it's worth

 

[JeezyMcNuggles]

I have an 800 watt Genzler Magellan class D amp, (running into one or two 1x12 Bergantino cabs, or a 2x10 Revsound cab, depending on venue/mood).

The amp is overkill for 90% of the gigs I play. Current band's gigs are lower in volume than others I’ve played in the past, and we typically have PA support. So I barely get the master volume on the Magellan over 9:00.

Tone wise, would I be better off with a lower powered class D amp that would allow me to crank up the master volume some? Does the master volume level affect tone in a class D amp, such that the more its cranked possibly giving a fuller tone? Or does that not matter with class D amps?

Yes, I do understand class D amps are not going to do what tube amps do when they are cranked.

Thanks.

I notice that they start to open up after half master. But, that's me. The increase in volume and power could just be that.

 

[ImTheOnlyOne]

Analogy time. Ever been to the gym and had a trainer push you past your comfort zone? I mean a push past what your body can recover from. Not "Hold it 20 more seconds," or "Come on, give me five more!", but "[k-klink] let's add more plates and do it again!", resulting in damage.

No question a well designed and built amp can electrically deliver whatever power its Master Volume allows, but that amp runs into electro- mechanical resistance.

Your amp is your workout effort, and your cab is the workout station. Stations rarely require strictly linear effort across the full range of motion. If the exercise demands more than you've got at some point, then you might shake or break.

So, the lesson then is, the more you exercise your cabinets, the stronger and more toned your amp becomes...? Oh man. Analogies are hard sometimes.

OK, so your bass is a car...

 

[agedhorse]

Or not.

 

[sheesh]

I wouldn't want to be using my 440 watt Glockenklang Soul on one of those 10% of your gigs that need more oomph.
OTOH I use an 800 watt class D head for cocktail jazz all the time.
View attachment 5366763
It definitely is better to have extra wattage & not need it than vice versa IME.
I do have to be a little careful with the 1x10; 500W @ 8Ω could fry that woofer if I tried to make it do the work of a 1x12 or 2x10. But with a little common sense I've gone many years without incident. So I have no plans to get a lower wattage head for those jobs.
With solid state heads, I've found the "mojo" (i.e. preamp compression and/or distortion) is usually best conjured with the input gain.

I am glad you posted because I bought the Q 800 bass block recently. For a long time I used the GK MB200 with one or both of those Peavey Trace Elliot 10s. Recently I also got the TraceE 2x8.

I am trying to understand my perceptions of using these two different amps with those speakers. For some reason I get this feeling that the GK MB200 is better matched to those speakers and the Quilter is "too powerful" but your post reassured me that I need to spend more time with the combinations and just listen more. (I am also considering getting another TE 2x8 for the Quilter like I read about, but they aren't available right now)

The GK MB200 only has a gain, so part of my struggle is understanding the relationship between the volume on my bass, the gain and the master on the Quilter. So I go play around with low gain, high master . . . high gain, low master . . . and also lowering the volume on the bass instrument . . .

 

[dhagopian]

It's not the amp or speakers as much as it is your ears and the human perception of hearing versus frequency. This is very much built into some lower powered amps amps to compensate for low volume applications.

Sure but that's what we mean when we talk about sound right? It's like color is a reflection of light in a particular way but no one says "that thing isn't really the color blue - it's just the way you perceive it." Of course but that's what we mean by "that thing is blue." Who's the intended listener to these amps/speakers? Humans I assume.

 

[bottomzone]

I like to have extra headroom.

 

[Jefenator]

I am glad you posted because I bought the Q 800 bass block recently. For a long time I used the GK MB200 with one or both of those Peavey Trace Elliot 10s. Recently I also got the TraceE 2x8.

I am trying to understand my perceptions of using these two different amps with those speakers. For some reason I get this feeling that the GK MB200 is better matched to those speakers and the Quilter is "too powerful" but your post reassured me that I need to spend more time with the combinations and just listen more. (I am also considering getting another TE 2x8 for the Quilter like I read about, but they aren't available right now)

The GK MB200 only has a gain, so part of my struggle is understanding the relationship between the volume on my bass, the gain and the master on the Quilter. So I go play around with low gain, high master . . . high gain, low master . . . and also lowering the volume on the bass instrument . . .

Be advised that the notoriously-inefficient Acme can take more of a pounding than most other 1x10s out there. But that special high-excursion woofer can still be fried (DAMHIK).
I would definitely be careful, driving a pair of lightweight 1x10s with a full 800 watt potential. I wouldn't use that stack on too loud a job, or put my master volume above 9 or 10 o'clock. (I'd probably take those wattage markings on the Quilter with a grain of salt. I can't recall ever going past 12 o'clock - which they refer to as 160W - for big loud gigs I would NOT try to cover with pair of ELF cabs.)

 

[agedhorse]

Sure but that's what we mean when we talk about sound right? It's like color is a reflection of light in a particular way but no one says "that thing isn't really the color blue - it's just the way you perceive it." Of course but that's what we mean by "that thing is blue." Who's the intended listener to these amps/speakers? Humans I assume.

The perception of tone varies with volume, not unlike the perception of color shift with intensity. These are critical parts of psycho acoustics.

 

[fdeck]

Earlier GK amps had a nonlinear element such as a Class-A JFET stage, in between the input gain and master volume controls. Fiddling with both controls was a way to add a little bit of growl or grit to the tone. It's not unthinkable that some other amps employed a similar strategy.

 

[Jazzdogg]

I notice that they start to open up after half master. But, that's me. The increase in volume and power could just be that.

Kind of depends on the taper used when a specific volume control is chosen by the amp's designer.

Some amps seem really loud at a 9:00 or 10:00 setting, but don't get much louder after that.

Others don't seem terribly loud at 9:00 or 10:00, but continue to increase volume throughout the rotation of the volume knob.

 

[silky smoove]

I notice that they start to open up after half master.

What does "open up" mean?

 

[N4860]

What does "open up" mean?

It's the opposite of closed down.

 

[ImTheOnlyOne]

Sure but that's what we mean when we talk about sound right? It's like color is a reflection of light in a particular way but no one says "that thing isn't really the color blue - it's just the way you perceive it." Of course but that's what we mean by "that thing is blue." Who's the intended listener to these amps/speakers? Humans I assume.

"Grue"



And I defer to the TB sticky, wherever it's hiding, for agreed upon descriptive audio vocabulary.

 

[JeezyMcNuggles]

What does "open up" mean?

Oomph, roar, girth, meat, get non sterile

 

[NeilGB]

Interesting topic. I always thought my class D amp changed tone as I turned it up, especially in the first part of the volume controls range (7-10 o’clock). I think it is a combination of Fletcher Munson and my tendency to pluck the strings differently as volume increases (largely to reduce the volume). I am part of the amps negative feedback volume control system!

 

[Veldar]

Do you like the Class D clip compression?

I'm actually a big fan of the sound, but I don't get to do it much the Agi TH500 is bor ally overkill.

Having said that, if anyone knows a comp pedal that works the same way let me know