Class D amps sound inferior?

[Jim C]

Why I use my Mesa subway preampDI with any amp I play. I just plug it into the FX return and have at it. You'd be surprised at how similar all bass amps sound. Makes it easy to get my sound with any rig.

Wonder if there is a TT or WD inspired pre amp in the wings?

 

[Standalone]

Have you tried the new GK Legacy or Fusion S amps?

I’ve not. There’s just not enough weight penalty in a 700rb for me to seek out lighter modern variants. I truly feel the response in the amp as it responds to my sometimes heavy and expressive RH technique... the very slight difference in more modern amp designs isn’t so much about audible difference as a feel.

Maybe I’m a religious nut, but I truly do perceive a difference at least in the modern amps that I have tried.

You surely have more technical background than I do, but....

 

[agedhorse]

I’ve not. There’s just not enough weight penalty in a 700rb for me to seek out lighter modern variants. I truly feel the response in the amp as it responds to my sometimes heavy and expressive RH technique... the very slight difference in more modern amp designs isn’t so much about audible difference as a feel.

Maybe I’m a religious nut, but I truly do perceive a difference at least in the modern amps that I have tried.

You surely have more technical background than I do, but....

Perhaps you just like the entire execution of the older model, there are quite a few differences aside from the power amp. Designers are always evolving their designs.

 

[agedhorse]

It's not the tone...different preamps with the different power sections.

To my ear, the best Class D (Pascal) still doesn't have the grunt/girth and punch (front end attack) that the (I checked) A/B that the Thunderfunk has. It is twice the weight of a 9 lbs amp I give that much. But the day I can't grab a 20 lbs amp that sounds like it does. May as well give up the gym membership. lol

Perhaps you just prefer the sound and feel of the Thunderfunk execution regardless of the power amp?

 

[PhatBottomBass1]

Perhaps you just prefer the sound and feel of the Thunderfunk execution regardless of the power amp?

Hi, I know there is something to how a power amp charges, distributes and holds in reserve and how quick it can do it. Also, the real estate it takes up and it's material weight per watt.

I have assumed that this is possibly why Class D is LOUD but, to my ear, doesn't push as much through the fire hose as fast as this particular A/B design. I do know that the parts used to make it were tested for tolerances that are very tight. No slop!

I kid when I say he started out building a spaceship and ended up with a Bass amplification starship.

 

[Standalone]

Perhaps you just like the entire execution of the older model, there are quite a few differences aside from the power amp. Designers are always evolving their designs.

This may be true. But the 400, the 800, and the 700 are just where it’s at for me

 

[agedhorse]

Hi, I know there is something to how a power amp charges, distributes and holds in reserve and how quick it can do it. Also, the real estate it takes up and it's material weight per watt.

I have assumed that this is possibly why Class D is LOUD but, to my ear, doesn't push as much through the fire hose as fast as this particular A/B design. I do know that the parts used to make it were tested for tolerances that are very tight. No slop!

I don't find any of what you posted above to be true or accurate. I have designed my share of both classes of amp, and in double-blind listening tests with the identical preamp, it's quite possible to make them sound and feel such they neither can be reliably identified.

 

[agedhorse]

This may be true. But the 400, the 800, and the 700 are just where it’s at for me

Sure, and the preamps are quite different than most other amps.

 

[PhatBottomBass1]

I don't find any of what you posted above to be true or accurate. I have designed my share of both classes of amp, and in double-blind listening tests with the identical preamp, it's quite possible to make them sound and feel such they neither can be reliably identified.

So, are you saying that the charging, distribution, power reserve and cycle are concepts unfamiliar to you in power amps?

Also, are you attempting to table the concept that any given amp can be made to preform at the same specifications as any other amp on your work bench that no one can tell the difference?

That's a bold statement, bro.

 

[Jeff Scott]

Yeah... We had a different device for leaf shutters... It didn't get as much use because most folks using Hasselblads were sending them elsewhere for work if they were leasing or had a service contract for them. The leaf shutter system used phototransistors and a scope. I didn't get to play with it, and had my Mamiya Press lenses tested and CLA'ed by someone else there - they all have in-lens leaf-shutters.

I still have my SWC, and a couple of older lenses for my Busch Pressman D, and one for my Busch Pressman C. Most of my "serious" photography was with various view cameras over the decades (Wista, Horseman, Linhof, Ebony, Deardorff, plus others by friends of mine) So all those lenses had leaf shutters. As to Mamiya, I used to sell their Press cameras to Mexican wedding photographers along with Polaroid backs, back in the '80s. And have much experience with Mamiya 7s.

 

[agedhorse]

So, are you saying that the charging, distribution, power reserve and cycle are concepts unfamiliar to you in power amps?

Very much so, since I design around all these factors all the time. I have been designing commercial power amps for almost 40 years now. It's also why I know that that you are not really understanding a word that I am saying.

 

[PhatBottomBass1]

Very much so, since I design around all these factors all the time. I have been designing commercial power amps for almost 40 years now. It's also why I know that that you are not really understanding a word that I am saying.

I'm not an amp designer.

I do know the power doesn't go from the wall outlet to the speaker coil directly. Now, how a "valve" may work as opposed to say Class K is going to be different. I couldn't say regarding A/B. I am saying that 40 years of heavy tube design has to be different than various degrees of Class D efficiency.

I pointed out a theory of observed performance between a specific design and a power section under question regarding being "inferior." Clearly, I'm not the only one who hears a difference!

 

[agedhorse]

I'm not an amp designer. I do know the power doesn't go from the wall outlet to the speaker coil directly. Now, how a "valve" may work as opposed to say Class K is going to be different. I couldn't say regarding A/B. I am saying that 40 years of heavy tube design has to be different than various degrees of Class D efficiency.

I pointed out a theory of observed performance between a specific design and a power section under question regarding be inferior. Clearly, I'm not the only one who hears a difference!

You are attributing the difference to something that may in fact have nothing to do with it.

I have proven this several times during design prototypes where I have taken IDENTICAL preamps and mated them up to different power amps/power supplies and when matched up correctly resulted in indistinguishable bass amps under double-blind testing. Therefore, it's easy to confidently conclude that if no difference could be detected then there was no meaningful difference present.

Now there are ways to INTENTIONALLY make a power amp behave differently, but that is an intentional design approach to achieve a specific effect. For example, I have done exactly this when developing the damping control circuit in the WD-800 (to emulate a specific characteristic or design quirk present in the walkabout's power amp) and also in the TT-800 where I added a circuit that tracks the constant damping factor characteristic of the Bass 400.

When I say that class D and class AB can be made to sound virtually identical, I am not talking about tube power amps, nor am I talking about power amps that have particular quirks or tricks built in to create an effect or a particular characteristic other than a simple power amp. I have been working with and designing with this technology for many years, I hope you can appreciate where I am coming from.

 

[PhatBottomBass1]

You are attributing the difference to something that may in fact have nothing to do with it.

I have proven this several times during design prototypes where I have taken IDENTICAL preamps and mated them up to different power amps/power supplies and when matched up correctly resulted in indistinguishable bass amps under double-blind testing. Therefore, it's easy to confidently conclude that if no difference could be detected then there was no meaningful difference present.

Now there are ways to INTENTIONALLY make a power amp behave differently, but that is an intentional design approach to achieve a specific effect. For example, I have done exactly this when developing the damping control circuit in the WD-800 (to emulate a specific characteristic or design quirk present in the walkabout's power amp) and also in the TT-800 where I added a circuit that tracks the constant damping factor characteristic of the Bass 400.

When I say that class D and class AB can be made to sound virtually identical, I am not talking about tube power amps, nor am I talking about power amps that have particular quirks or tricks built in to create an effect or a particular characteristic other than a simple power amp. I have been working with and designing with this technology for many years, I hope you can appreciate where I am coming from.

That was informative.

I guess what I have read about Class K may have caused me to consider that other amps may work in a similar way. Transformers holding current and "stand by" to get tubes up and running to regulate the current and bias requierments of the compliment. I really was interested in why PASCAL is considered the flagship of Class D from Denmark? British valve amps have always been praised items, too. (Marshall/Hiwatt)

I will do some more independent research on Class D.

Thanks!

 

[Al Kraft]

Wonder if there is a TT or WD inspired pre amp in the wings?

I suspect that would be a steep hill to climb design-wise, but agedhorse usually likes to say that nothing is completely off the table. After watching him conquer the "pretty darn close to a Walkabout with more power challenge", I'd say most anything is possible...you just never know.

 

[tylerwylie]

There is something pleasing about standing in front of my rig with my Mesa WD800 where I feel like I'm getting kicked from behind. I hadn't felt that with an amp since I plugged into a DB751 with a DB112 at Bass Club Chicago way back in the day. I wonder if it's being able to set the power damping on the WD800 to high. Wonder what would win out in a a blind comparison - use some preamp pedal and run into the FX return on a couple high end class D amps and then do the same with like an SVT, DB751, GK800RB, etc and have like 3 mics picking things up (SM57 / ribbon mic / some LDC).

 

[PhatBottomBass1]

There is something pleasing about standing in front of my rig with my Mesa WD800 where I feel like I'm getting kicked from behind. I wonder if it's being able to set the power damping on the WD800 to high.

Wonder what would win out in a a blind comparison - use some preamp pedal and run into the FX return on a couple high end class D amps and then do the same with like an SVT, DB751, GK800RB, etc and have like 3 mics picking things up (SM57 / ribbon mic / some LDC).

Let me say this. I've used two of the Wayne Jones Audio 2X10Powered cabinets with Pascal 1000 top of the line Class D power sections. To my ear, the WJA preamp (designed around an Avalon 737) had nothing on an Aguilar DB680 Tube Preamp sound/tone wise. But, neither had the quality of a dampening like a tube amp likes from a sealed cabinet. (NV412/610/115)

Also, pushing a preamp pedal into something like this Class D power amp is not going to push it hard enough to preform in a significant way. (...thats what Wayne said and I found it to be the case.) It guess that it likes high octane fuel and sputters on regular.

 

[agedhorse]

That was informative.

I guess what I have read about Class K may have caused me to consider that other amps may work in a similar way. Transformers holding current and "stand by" to get tubes up and running to regulate the current and bias requierments of the compliment. I really was interested in why PASCAL is considered the flagship of Class D from Denmark? British valve amps have always been praised items, too. (Marshall/Hiwatt)

I will do some more independent research on Class D.

Thanks!

Well, class K is really only applicable to low powered amps (under say 5 watts) so I don't know how that applies to this discussion.

Transformers do not hold current and "stand by" to do anything. I don't understand how this applies either.

Some designers prefer Pascal, some designers prefer ICEPower, both are equally good products IMO. In the bass amp industry, the ICEPower platform has generally been considered the "gold standard" by most designers (based on the number of products that have adopted the platform). ICEPower is also a Danish company, the Pascal folks came out of ICEPower around 2006-2007. ICEPower started as a division of Bang & Oluffsen in ~1998.

The first product I designed using an ICEPower module was back in ~2003 (a pro audio product for a British company) , long before Pascal existed with a commercial product (which was around 2008).

 

[PhatBottomBass1]

Well, class K is really only applicable to low powered amps (under say 5 watts) so I don't know how that applies to this discussion.

Transformers do not hold current and "stand by" to do anything. I don't understand how this applies either.

Some designers prefer Pascal, some designers prefer ICEPower, both are equally good products IMO. In the bass amp industry, the ICEPower platform has generally been considered the "gold standard" by most designers (based on the number of products that have adopted the platform). ICEPower is also a Danish company, the Pascal folks came out of ICEPower around 2006-2007. ICEPower started as a division of Bang & Oluffsen in ~1998.

The first product I designed using an ICEPower module was back in ~2003 (a pro audio product for a British company) , long before Pascal existed with a commercial product (which was around 2008).

I was using a Stewart World 2.1 for a time @ 17 lbs bridgeable to 1300 watts @ 8 Ohms and Class K was listed on the unit (thats how I became aware of Class K)

My use of other power regulation features in amp types are not related beyond electricity in amplifiers and you well know it. I accept you work currently for Mesa, that's great, and I understand the COMMERCIAL interest. I also accept that you have a following on TB and I'm not trying to upset your Apple cart. Good information is always better than academia bravado.

 

[Jack Deth]

I need a beer after reading this whole thread. I was waiting on someone to mention quaternions and measuring time relative to the distance a photon travels through a test medium, or perhaps atomic scale qbits vs. quantum annealing energy states. I’m just gonna go play my Dingwall and be happy...