Does class D have the Heft of SS

[JimmyM]

This is no different than saying I A/B'd an Ampeg SVT7 Pro and a GK 400RB IV and there was a difference. Or any other two differing amps, regardless of power class makeup. Of course they weren't the same amp, they weren't designed the same, and they weren't intended to produce the same results.

It actually is different, since pro level power amps are designed to not project any idiosyncracies of their own onto the overall sound, and they're designed to have imperceptible distortion. This, according to many power amp designers, is supposed to mean that power amps designed with these goals should all sound the same.

 

[agedhorse]

It actually is different, since pro level power amps are designed to not project any idiosyncracies of their own onto the overall sound, and they're designed to have imperceptible distortion. This, according to many power amp designers, is supposed to mean that power amps designed with these goals should all sound the same.

Unless they are intentionally designed otherwise (like the Crest CA series), or exhibit different overdriven characteristics (which many in fact do, and I've mentioned thisquite a bit before).

As a GENERALITY, pro audio power amps will sound very similar (under the gain matched conditions, which all comparison testing should be done) when operated in their linear (below clipping) region.

 

[agedhorse]

I a/bd a carvin dcm 1500 and crest pro lite 2.0. There was a difference

If you perceived a difference, buy the one that you perceived to be "better".

Don't forget Crest 2.0's 2k power rating is "burst". An RMS rating may be closer to half that. I upped my rig to a 3.0.

Burst ratings are yet another (and yes, valuable under some conditions) way to measure output under short term use. Burst can be stated in peak watts or "RMS" watts, and the mark to space ratio can be different as well. It is used to describe the dynamic capabilities of an amp, the needs of which might vary by the frequency band being reproduced. Sub frequency bands typically need a longer burst period compared with say a high frequency band amp due to the nature of the respective waveforms. This sort of data might be used by modeling amp algorithms to mimic the dynamic behavior of a modeled amp.

I wrote in the 4th post that I was waiting for my 1st class D amp... I bought a 7lb Hartke TX600 a year ago, only used it 5 times and went back to my 42lb LH500 which for a SS I feel has more headroom and tone. The class D was loud but just has a different sound. Just cant explain it. Not enough oomph? When I traded the TX600 in at the local music store they were stacked to the ceiling with used ones. I guess I'm not alone.

Well, those are 2 different amp, right? You might be hearing intentional design differences between the models. If the TX-600 doesn't work for you, there's nothing making you use it, and nothing from preventing you using the LD500, right?

I would say that from this one might conclude that the TX600 is lacking. Maybe something to do with the HPF.

Could certainly be a difference in design intent (of course I don't know for sure), it could be other things as well.

 

[AE1]

It's not a matter of giving in or changing the world, it's about educating yourself about a topic so that what you say makes sense.

"Making sense" must have context. My context is where I have come from. None of your responses have had context or facts - just offhanded dismissal. They have not added new knowledge.

My posts actually did make sense to those folks who reported they liked what I said. I assume they understood it.

I am sure your electronic knowledge is vast, but that results in you having to make hard commercially tempered design choices between competing options when designing a product - not an easy task. You obviously prefer Class D amps over lead sleds. The market will not let you do otherwise.

But Class D comes in many forms, as do their power supplies which can be conventional or switchmode or other. Since Class D is more efficient than AB there is a clear advantage in large installations where power consumption is critical, but for the one off user it would appear that less weight and cost offer the main advantages.

120V mains is a limiting factor for larger amplifiers so for those who need it, the more efficient Class D amps offer much more prospective audio power in that circumstance.

I'm happy where I am in my old-school simplicity - but that does not make my knowledge redundent - just historic and still relevant.

[QUOTE=""You might try an EE degree, but once you get the education you will see why your arguments make no sense. Belief and blind faith will only get you so far without the underlying understanding, and once you understand your beliefs may change."

What is missing in your arguments is presentation of cause and effect relationships - ie evidence.

Unless you can identify those then all the EE degrees in the world will not resolve the challenges of venturing into the unknown - which is where bass players go every time they pick up a bass and play - unless we are robots. The history of recorded music is one of constantly changing sounds so musicians are ever chasing difference through experimentation and innovation. We musicians also operate in a competitive commercial environment where we sell our skills. Amplifiers are just one part of our toolkit.

Nowadays "effects" are just as important as the amp and preamp - which says no matter how great the amp is it is still not enough to satisfy many bassists.

[QUOTE="I didn't spend 6 years at my university for nothing. I don't have a need for beliefs without the science to back them up, I at least owe that to the customers who play what I design (that's kind of how my morals roll). I'm not selling magic potions or snake oil."

Some amp designers obviously went to a different school, determining that a solid capacitor bank is worth the extra cost and weight. Maybe they are stuck in the past too. Beneficially increasing capacitor size was the theme of my posts.

[URL]https://i.ytimg.com/vi/9uB_75GtRyE/hqdefault.jpg[/URL]
Invalid Link Removed

The irony here is that your customers will make their choices not based upon science but on their perceptions, beliefs and subjective assessments - tempered with hearsay from threads such as this one - and "blind faith" in the salesperson. Customers do discern between products and will choose according to those parameters.

So until someone devises a scientific method for comparing amps then that is the way it will remain.

That is also how bassists will determine if Class D amps deliver more heft than Class AB - that is if they can discern any difference at all.

see also Invalid Link Removed[/QUOTE]

 

[agedhorse]

I design amps that PLAYERS want to play, this is how I work.

I actually do not prefer class d over any other class (and I have designed with all classes), in fact I enjoy the process of designing class AB amps more, but because I UNDERSTAND how they work, I also understand the inherent limitations that this topology presents, so for some player's needs class D is simply a better approach to achieve their goals.

Hobby-tinkers are free to believe whatever they want about the performance of their products, and the mythology contained within. I do not have such freedoms. The market governs the performance and what they perceive about my products, that's who I am designing for.

Hobby-tinkerers are also free from having to abide by safety and EMC regulations. I MUST comply with many strict regulations covering international safety and EMC compliance. I do not have the option to just "wing it" and hope for the best. I do everything in my power to insure a safe, reliable product. Burning down somebody's house or electrocuting them is simply not an option. Your earlier comments about fuse sizing and placement are simply irresponsible because of the potential for damage. Of course this is kind of approach is prohibited by all safety agencies.

This is what separates engineers from hobby-tinkers. Engineers MUST know, hobby-tinkerers THINK they know.

 

[Dave Hill]

All the nice PA systems I've been playing through for the past 5 years or so use powered (class D) boxes and they leave nothing to be desired.

 

[JimmyM]

All the nice PA systems I've been playing through for the past 5 years or so use powered (class D) boxes and they leave nothing to be desired.

Same here, but I talk to sound techs about the differences and they hear them, too. But who wouldn't rather carry one or two racks of 10 lb power amps than 5 or 6 racks of 30 lb power amps?

 

[Loring]

Same here, but I talk to sound techs about the differences and they hear them, too. But who wouldn't rather carry one or two racks of 10 lb power amps than 5 or 6 racks of 30 lb power amps?

hopefully they are in wheeled road cases...

 

[JimmyM]

hopefully they are in wheeled road cases...

Usually, unless they're 6-space or less

 

[mikewalker]

I was prepared to be underwhelmed by compact Class-D amps, but I now own two (a Traynor and a Carvin) that are completely satisfactory in terms of "heft", "thump" and "rattling-the-walls". Couple hundred watts through a nice cabinet does the trick for me. (extra large stages: double up the rig)

 

[Brad Johnson]

I haven't talked to a pro sound person in a long time who didn't prefer what they bought/used over older, heavier kit. They're getting the results they and their clients want. Several of my recent gigs have been amongst the absolute best live sound I've ever experienced. But that is hardly about gear alone... it also required people who knew what the heck they were doing. And by the same token, inept engineers/techs can screw up even the best setup.

 

[JimmyM]

I haven't talked to a pro sound person in a long time who didn't prefer what they bought/used over older, heavier kit. They're getting the results they and their clients want. Several of my recent gigs have been amongst the absolute best live sound I've ever experienced. But that is hardly about gear alone... it also required people who knew what the heck they were doing. And by the same token, inept engineers/techs can screw up even the best setup.

Agreed. And you're right that none of them want to go back. But is that because of the weight and travel primarily? I believe it has a heck of a lot to do with it. Sure, they can get great sounds with it. That can't be argued. But I'd like to know how many would go back to SS or tube power amps if they weren't so heavy and large. Maybe we should conduct a poll. I'll head it up for $20,000.

 

[bucephylus]

"Making sense" must have context. My context is where I have come from. None of your responses have had context or facts - just offhanded dismissal. They have not added new knowledge.

My posts actually did make sense to those folks who reported they liked what I said. I assume they understood it.

I am sure your electronic knowledge is vast, but that results in you having to make hard commercially tempered design choices between competing options when designing a product - not an easy task. You obviously prefer Class D amps over lead sleds. The market will not let you do otherwise.

But Class D comes in many forms, as do their power supplies which can be conventional or switchmode or other. Since Class D is more efficient than AB there is a clear advantage in large installations where power consumption is critical, but for the one off user it would appear that less weight and cost offer the main advantages.

120V mains is a limiting factor for larger amplifiers so for those who need it, the more efficient Class D amps offer much more prospective audio power in that circumstance.

I'm happy where I am in my old-school simplicity - but that does not make my knowledge redundent - just historic and still relevant.

[QUOTE=""You might try an EE degree, but once you get the education you will see why your arguments make no sense. Belief and blind faith will only get you so far without the underlying understanding, and once you understand your beliefs may change."

What is missing in your arguments is presentation of cause and effect relationships - ie evidence.

Unless you can identify those then all the EE degrees in the world will not resolve the challenges of venturing into the unknown - which is where bass players go every time they pick up a bass and play - unless we are robots. The history of recorded music is one of constantly changing sounds so musicians are ever chasing difference through experimentation and innovation. We musicians also operate in a competitive commercial environment where we sell our skills. Amplifiers are just one part of our toolkit.

Nowadays "effects" are just as important as the amp and preamp - which says no matter how great the amp is it is still not enough to satisfy many bassists.

[QUOTE="I didn't spend 6 years at my university for nothing. I don't have a need for beliefs without the science to back them up, I at least owe that to the customers who play what I design (that's kind of how my morals roll). I'm not selling magic potions or snake oil."

Some amp designers obviously went to a different school, determining that a solid capacitor bank is worth the extra cost and weight. Maybe they are stuck in the past too. Beneficially increasing capacitor size was the theme of my posts.

https://i.ytimg.com/vi/9uB_75GtRyE/hqdefault.jpg
Invalid Link Removed

The irony here is that your customers will make their choices not based upon science but on their perceptions, beliefs and subjective assessments - tempered with hearsay from threads such as this one - and "blind faith" in the salesperson. Customers do discern between products and will choose according to those parameters.

So until someone devises a scientific method for comparing amps then that is the way it will remain.

That is also how bassists will determine if Class D amps deliver more heft than Class AB - that is if they can discern any difference at all.

see also Invalid Link Removed

[/QUOTE]
Just a quick question:

Which Class D amps have you gigged?

Part of the problematic part of this discussion is that everyone isn't dealing with the same data set.

You are engaged in a theoretical discussion with @agedhorse; but, you also have stated, quite correctly, that the proof is in the actual performance. In fact, that is NOT at all at odds with scientific work. I worked in R&D for 35+ years; and our saying was "theory guides, data decides." Nothing at all incorrect with doing controlled experiments and drawing conclusions based on empirical results. We do it all the time. You don't need a BS degree to do it. Your experience is legit evidence; but, you also need to be aware of the limitations.

So, it might help to describe some of your Class D experience on the gig; and talk about what worked and what didn't.

Every player has different gigs and different sound needs. Cats have preferences, even between different tube amps, for example. In my case, I have actually put Class D next to the SVT and done gigs with both. IME, you can get excellent results with well designed Class D; but, drawing conclusions from, say a Behringer (not to pick on them) design, is not broadly applicable to the more carefully designed Class D amps.

Each to their own; but, we should avoid implying that cats are lesser players because they choose a different kind of amplification system. That is simply not the case. And, making generalizations about a Class of amps without broad empirical experience is also questionable. For example, "I tried the Behringer and it was deficient, therefore all the other Class D amps, such as Bergantino, Demeter, Mesa, Genzler, Quilter etc are deficient," is also not sound logic.

Just saying'.

 

[Jim C]

Remember back in the early 70's when transistor guitar amps were being introduced?
Nearly all had the ad copy of "sounds just like a tube amp".
IMO, the magic was / is the distortion characteristics.

There are very few professional rock guitar players that prefer a SS amp over tubes.
The market has spoken.
I believe the criteria for good power amplifier design is defined by raising the output level with a minimum amount of change to the wave form which is not what rock guitar players are looking for.

Many bassists are looking for a clean tone to which I immediately assume is a great player, great bass, great DI box, N eve or SSL console (my preference) and the latest trick monitors of the day.
This is not what is considered clean tone to others.

I have played through old SVT's with out of spec components that sounded great; technically the don't scope as well as a unit in spec, but that really isn't the question.

The question is what do YOU like.
Perhaps the led sled that has more "heft" really is inferior when evaluated based on normal design and engineering criteria. Maybe it's better. This doesn't matter.
Totally agree with the engineers here who are trying to keep the facts inline.
They have test equipment that can measure the change in wave form, distortion characteristics, etc.
This is how they evaluate and improve their designs (IMO).
Car guys use a dynamometer to evaluate gains in horse power and torque.
You can't change the laws of physics, so why keep beating these dead horses?
Embrace the idea that what sounds musical to you, may not be technically the best.

I don't know why I prefer the old school amps and have given up trying to determine the reason.
I have probably spent a few hundred hours over the last 20 years with my trusty Ampeg selector switch A/B ing amps and cabinets both alone and within a band context.
Funny how playing solo and playing with a band doesn't favor the exact same gear.
I have never done a true double blind listening test (with accurately measured volume levels) and am confident that 95% of the folks on this thread have not either.

It would be much more useful to describe what you like and the related gear that gets you there.
My dad had a master's in EE. Back in his day (tube amps) quality was often measured by the pound.
He taught me valuable lessons about truly understanding a subject before proclaiming ones' expertise.

At 59, I want to find a lightweight amp that meets MY criteria and I'll keep looking with an open mind.
25 years from now when audio advances even more so, the ad copy may read "sounds just like an old Class D amp".

 

[GreyBeard]

Just a quick question:

Which Class D amps have you gigged?


So, it might help to describe some of your Class D experience on the gig; and talk about what worked and what didn't.



I currently have an Ampeg PF-500 and a Fender Rumble 500 head. I also have a Sunn 200S that is out of service at this time. In the past I've done the preamp-power amp thing. I had an Alembic F1-X, Line6 Pod-Pro, Ampeg SVP-Pro that I used with a Carvin and then a QSC PLX1202. With 1st a Hartke 4.5XL then a SWR Triad and a Whappo Jr. Now I'm using the pf-500 and the Rumble with either a Sunn Sorado 2x15 with EVM-B's, a Hartke 115XL and most recently a BFM S15. I have found the class D Rumble and PF every bit as satisfying as any other amp I've owned. Probably the best rig I have is the Ampeg PF-500 through my heavy old Sunn 2x15, if you like old-school.

P.S. What some call "heft" other call "loose bottom end"

 

[Brad Johnson]

Agreed. And you're right that none of them want to go back. But is that because of the weight and travel primarily? I believe it has a heck of a lot to do with it. Sure, they can get great sounds with it. That can't be argued. But I'd like to know how many would go back to SS or tube power amps if they weren't so heavy and large. Maybe we should conduct a poll. I'll head it up for $20,000.

I have friends who regaled me with how awesome Crest CA9 power amps sounded and that they didn't care about the weight. I tried their rigs and the amps sounded fine... but they didn't blow me away as much as they said they would. I had an Aguilar DB750 and it equaled my rack setup fingerstyle but came up short for more percussive work. I had a 70's SVT rig that, while it worked fine, it wasn't for me and sound was more of a factor than weight. The engineers I know are mostly the same way... if they got demonstrably better sound with heavier amps they'd break them up in more racks for portability's sake and keep it moving.

So if I could find an SVT the size of my Quilter... I'd still use my Quilter. I tried my rack and Quilter on the same gig... the rack didn't sound better. Dead man walking .

I'd be willing to carry around bigger gear if it really made the clouds part. But that's what my liddle' stuff does.

 

[seamonkey]

I a/bd a carvin dcm 1500 and crest pro lite 2.0. There was a difference

Those being power amps did you match the gain?

eh - it doesn't matter - you could be in that 99 percentile that can hear things others can't.
It just so happens that there are many 99 percentile around here
Some shold be using their abilities for the betterment of power amplifiers in the world.

 

[alaskaleftybass]

If class D doesn't work for you, for whatever reason, the world is awash with good used class AB amps for pennies on the dollar. I hauled off about 500 pounds of class AB amps (most working) to the scrapper because it wasn't worth the cost of selling and shipping it. In fact I could barely give it away for the cost of shipping.

please let me know if you ever drag amps to the dump again!!!! LOL

 

[Wicked G]

please let me know if you ever drag amps to the dump again!!!! LOL

Completely agree. If you ever need to dump any Walkabouts or hidden GBE750's, please contact me, I'm pretty sure I could find a way to cover the shipping.

I wrote in the 4th post that I was waiting for my 1st class D amp... I bought a 7lb Hartke TX600 a year ago, only used it 5 times and went back to my 42lb LH500 which for a SS I feel has more headroom and tone. The class D was loud but just has a different sound. Just cant explain it. Not enough oomph? When I traded the TX600 in at the local music store they were stacked to the ceiling with used ones. I guess I'm not alone.

I wouldn't lump all Class D on your experience with that one amp. There have been numerous complaints that that particular amp is just plain lacking.

 

[dbase]

Completely agree. If you ever need to dump any Walkabouts or hidden GBE750's, please contact me, I'm pretty sure I could find a way to cover the shipping.


I wouldn't lump all Class D on your experience with that one amp. There have been numerous complaints that that particular amp is just plain lacking.

Yes, I found that out because I use a Fender Rumble 150 at a practice studio into a 4x10 and it sounds good.. not great but good. I prefer tube but too damn heavy at my age. I do use the PA at times which is 1000 watts into two JBL 15's and it sounds OK and they are class D powered. I was really hoping the TX600 would solve my weight problems plus add 100 more watts to the mix than my LH500 but I was sadly disappointed. I took a beating on trading that amp. Live and learn.