Do class D amps sound different?

[agedhorse]

There are many ways to exploit different aspects of the various class D amp modules, capitalize and expand on the strengths while avoiding or designing around the weaknesses. We can also add supporting circuitry to alter a variety of performance parameters.

IMO, this is why amp's with the same module can perform so differently.

 

[Old Garage-Bander]

Some amp companies engineer their own Class D power modules.

That may be the case.
Do you know the names of any of the MI amp builders who design and build their own Class D power output stages?

It just seems like it would be a real cost savings to not employ an engineering design team and tool up manufacturing processes and assembly plants when someone else is already making something that you can drop into your MI amplifier. Especially when the design goals for a power amp should be the same regardless of who makes it. That that goal being that it does not change the sonic characteristics of the input audio.

Aren't different amps typically known for their signature sounds and aren't those sounds more built into the pre-amp stages that power amps?

If the difference is in the tone stack of the preamp and not the power stages, and assuming clean amplification, it shouldn't matter what the power stage is, should it?

 

[Old Garage-Bander]

I would fully expect things like how EMI filtering and power supply design and integration are addressed (for example) would make significant differences. Some of these differences might manifest as undesirable artifacts or performance across all operational regimes while others might tend to show up only when the amp is driven to its limits. Once again folks like agedhorse would be much better able to address this than me.

I guess I'm being more theoretical than practical. I assume the amps are driven within their design parameters, sans clipping, and the output looks like the input only larger. Once you reach the design limits all bets are off. And certainly you can design something to operate at the edge, but how do you compare that? It becomes subjective.
The original question is "Do Class D amps sound different?"
The OP specifically ask about FET amps operating class A/B vs Class D (MOSFET) amps.
Clean amplification should sound the same in either case.
I can't speak to sound differences when these two types of amps are driven to distortion.

 

[TrentB]

That may be the case.
Do you know the names of any of the MI amp builders who design and build their own Class D power output stages?

It just seems like it would be a real cost savings to not employ an engineering design team and tool up manufacturing processes and assembly plants when someone else is already making something that you can drop into your MI amplifier. Especially when the design goals for a power amp should be the same regardless of who makes it. That that goal being that it does not change the sonic characteristics of the input audio.

Aren't different amps typically known for their signature sounds and aren't those sounds more built into the pre-amp stages that power amps?

If the difference is in the tone stack of the preamp and not the power stages, and assuming clean amplification, it shouldn't matter what the power stage is, should it?

I believe that Quilter and Peavy use their own proprietary class D power modules.

 

[arbiterusa]

Do you know the names of any of the MI amp builders who design and build their own Class D power output stages?

Markbass is one. Pretty sure Quilter does as well.

 

[Joebone]

Returning to the original question. Heart? Brain?

What do your EARS your BOOTY, your BANDMATES and the DANCE FLOOR tell you?

Yeah, and maybe even your drummer, as well?

Me, still feelin’ it best with good A/B, but good D is catching up, quickly. And the class of power amp won’t matter if the pre-amp isn’t bringing it.

 

[interp]

I’ve mentioned this before, but I used to work with a blind keyboard player who had other-worldly hearing ability (for example, I was walking with him around his neighborhood and he identified his house by the particular sound of our footsteps bouncing off the front of his house. He also had absolute pitch.)

He could not differentiate between my class A/B or D amps played through the same instruments or cabs.

 

[red_rhino]

Follow your brain!

LOL! I've been on the lookout for a new signature.

 

[xnewyorka]

I’ve mentioned this before, but I used to work with a blind keyboard player who had other-worldly hearing ability (for example, I was walking with him around his neighborhood and he identified his house by the particular sound of our footsteps bouncing off the front of his house. He also had absolute pitch.)

He could not differentiate between my class A/B or D amps played through the same instruments or cabs.

Wow - now THAT is what I would call a meaningful data point!

And I agree with it.

When I first learned about Class D, I thought it was an interesting engineering accomplishment, but I was sure I was not going to like it because the THD figure was so high. I am accustomed to listening to extremely clean sound reproduction with ultra low THD and ultra low noise floor, so I have become rather picky about sound quality.
To my great surprise, all four pieces of Class D equipment I have listened to did not have any THD issue that I could hear. And all of them except the Markbass piece sounded completely quiet, or at least quiet enough for my taste, with no input signal.

I have not studied or even seen any of their schematics, but my instincts say that the differences between the various models is primarily due to the tone-shaping characteristics of their respective preamp sections. The nature of Class D amplification is that it is not likely to add or subtract much from the signal at all, it just makes it louder. Everything between your fingers and the amplifier stage input is what mostly determines how it sounds.
The most important factors are: string type and condition, pickup design and placement, fingering technique and placement, tone control settings, speaker type, cabinet volume and design, and cabinet placement within the room and the room's acoustics. (Assuming no pedals in use.) Amplification Class is not in that list. If ANY one item on that list is less than ideal, your sound will suffer a lot. To a slight extent, the instrument body's and neck's density and resonance affect the tone as well, but not sufficiently to destroy your sound.

One of the things that is most disappointing is how the best talent and the best equipment in the world can be almost completely overridden by disastrous room acoustics. That is when having a sound engineer worth his salt really becomes vital.

 

[Sauron_]

For me A/B sound better than D. And I can't explain why...is like progressive music, you can't describe it but you know it when you hear it...

I've had a Tone Hammer 500, Markbass Little Mark, Warwick X-treme and GK RB1001, being the GK the best of them all.

 

[chris_b]

Do they sound different than prior gen A/B designs?
My heart wants to believe old school FET amps are better, but my brain tells me it isn't true.

Never mind what your heart is saying, what are your ears telling you.

My first handful of amps were tube. I've been through all formats and can afford to buy any amp on the market. Right now my current D Class amps out perform all of my previous amps. To me they sound better.

 

[baxter_x]

I friend of mine, bassist too, told me class D amps sound diferent.
I tried the GK MB500 (class D) and felt it was sounding exactly like my Mesa M9 (classA/B). To me the power section technology doesn't do much. It's mainly the preamp.

 

[baxter_x]

I

My first handful of amps were tube. I've been through all formats and can afford to buy any amp on the market. Right now my current D Class amps out perform all of my previous amps. To me they sound better.

I couldn't agree more! Follow your ears not what others say.

 

[MultiScaleMale]

They both take electricity from the wall and convert it to current for the speakers. One makes a ton of heat doing it, the other doesn’t. So when your brain looks at a four pound amp and thinks it can’t sound as loud as a thirty pound amp, remember, the wall is doing the work.

 

[BadExample]

That may be the case.
Do you know the names of any of the MI amp builders who design and build their own Class D power output stages?

It just seems like it would be a real cost savings to not employ an engineering design team and tool up manufacturing processes and assembly plants when someone else is already making something that you can drop into your MI amplifier. Especially when the design goals for a power amp should be the same regardless of who makes it. That that goal being that it does not change the sonic characteristics of the input audio.

Aren't different amps typically known for their signature sounds and aren't those sounds more built into the pre-amp stages that power amps?

If the difference is in the tone stack of the preamp and not the power stages, and assuming clean amplification, it shouldn't matter what the power stage is, should it?

Carvin, I believe, was on the lsit until so recently. http://carvinimages.com/schematics/45500_revf.pdf

As far as the Class D power section using a module:

There are many ways to exploit different aspects of the various class D amp modules, capitalize and expand on the strengths while avoiding or designing around the weaknesses. We can also add supporting circuitry to alter a variety of performance parameters.

IMO, this is why amp's with the same module can perform so differently.

Andy has expounded several times on how designing these amps can be accomplished in a manner that the breakup from clipping and recovery can be desirable. I'm sure there are others, but the D800 I believe is designed to distort nicely into the 10% range. Try that with a $300 (new street price) class D

 

[jaymelewis]

Different is a word that sometimes gets interpreted as not as good. They are different, sure, but I'd play either one in a heartbeat (depending on what I need for the gig).

 

[Coolhandjjl]

They both take electricity from the wall and convert it to current for the speakers. One makes a ton of heat doing it, the other doesn’t. So when your brain looks at a four pound amp and thinks it can’t sound as loud as a thirty pound amp, remember, the wall is doing the work.

THIS ^^^

 

[MVE]

It doesn’t help perceptions that certain boutique amp builders (that will remain nameless) state explicitly in their manuals and other “hype” that class D doesn’t have the “oomph” of A/B.

 

[Gormsgade]

Very much to m own surprice I ended up favoring class D.
I've been using a cheap Crown XLS 1501 driving two Aguilar GS212 for the last couple of years.
A pair of Crown Macrotech 1200 came up for sale locally. I grapped them, paid good money to have them serviced
and brought back to as new performance. Even with each one of then driving their own kabinet,
I ended up preferring the cheap class D amp and subsequently sold the Macrotech's. It was as if the Class D simply
couldn't run out of power and dynamic reserves. Wonderful amps but the old Macro's but a cheap class D can still do an outstanding job.

 

[Altitude]

I really don't understand why people can't get over the fact that a class D amplifier and SMPS are easily capable of doing the same thing as a much less efficient amplifier design approach which features boat loads of waste heat, tons of weight and gargantuan sized components as part of the baggage of that less efficient approach.

It’s human nature to endure hardship and to rationalize why we must. That’s essentially the basis of organized religion, or was until recently.