Class D "digital" amps. Opinions on performance

[chadds]

The moderators did a great job of taking care of the few bad apples that resulted in all that negativity. As you can see, this is nice and polite, and most discussions are very good in the amp forum now Interesting topics to me, and I have learned a lot through the years on this topic. Great place to get info for someone considering a purchase of an amp IMO.

Until someone mentions a "P"articular bass.

 

[Doug Parent]

My favorite Class D is the Markbass F1/F500.

Since working with the Genz Benz Shuttle Max 9.2 I've moved on from the Markbass, although I have yet to find anything that sounds like the F1 except perhaps a Yamaha PB-1 pre/power set-up.

 

[Calaverasgrande]

I know in live sound engineering circles a lot of us were early adopters of the Stewart amps. Which to my knowledge were some of the first SMPS/Class H products. Me and a few of my colleagues where pretty enthusiastic about them, but they had reliability issues and as stated above, you had to buy "more watts" to get the same kind of slam you may have been used to with a lead sled design. I think some of this has nothing to do with whether a SMPS/Class H amp is able to get as loud as the older designs. Rather that sometimes sound guys intentionally lean on their amps rather hard to get the limiters to kick in. On a few models this will give you the impression of a bigger louder sub.
At one club I used to work at with Billy Anderson, he would insist that we absolutely punish the CS800 driving our subs. He wasn't happy unless he saw an almost unblinking red light on both channels. I'll admit, it did sound good most of the time. But it was hardly punchy.
This kind of behavior doesn't seem to work with the more modern amp designs. You actually have to observe "real sound engineering" practice and maintain headroom, gain structure etc.
I do know a few guys that went with Class H amps for the subs and low mids with class AB amps on the mid/highs. I think that is more for the super nerd factor than any tangible benefit though.

 

[JimmyM]

+1 If you don't care about size and weight, then that opens up your options for a few more designs and brands, some of which sound quite good. As far as 'not caring for them', I'm not sure what 'them' is. There is VAST variability within any class of product. That would be like saying 'I don't like the sound of heavy amps', which of course makes zero sense. I love some, I dislike some, just like with small amps, light amps, tube amps, big solid state amps, etc., etc.

The trouble starts IMO when one lumps a whole class of things together and just says 'well, they all sound like this'. Makes little sense. There is just as much variability within class of amp design (tube, solid state, whatever) as across those different categories.

There are also commonalities of tone in the designs of a given amp topology. To put it all on the design itself while calling the format irrelevant is to deny reality IMHO. If what you said was true, then how come nobody makes either a micro or traditional SS amp that sounds identical to the SVT, even after decades of amp manufacturers trying to? And how come nobody makes a tube amp or micro that sounds identical to the GK 800RB or Acoustic 360? Design choices? I don't think so. Each format has strengths and weaknesses, and as of yet, I've yet to hear any true duplication. Heard a lot of "close but no cigar," but not once any duplication.

 

[KJung]

There are also commonalities of tone in the designs of a given amp topology. To put it all on the design itself while calling the format irrelevant is to deny reality IMHO. If what you said was true, then how come nobody makes either a micro or traditional SS amp that sounds identical to the SVT, even after decades of amp manufacturers trying to? And how come nobody makes a tube amp or micro that sounds identical to the GK 800RB or Acoustic 360? Design choices? I don't think so. Each format has strengths and weaknesses, and as of yet, I've yet to hear any true duplication. Heard a lot of "close but no cigar," but not once any duplication.

For the same reason that no-one makes an amp that sounds exactly like an LMIII or an Aguilar TH500. The sound of a given amp is due to dozens of components, and hundreds of interactions among components, many of which are 'non linear'.

I've NEVER heard an amp of ANY type by one manufacturer sound like another amp of ANY type by another manufacturer, or even within manufacturer. No class D/SMPS amp sounds like another class D/SMPS amp... even amps that use the same ICE module.

Again, you are off the mark on this.

 

[JimmyM]

For the same reason that no-one makes an amp that sounds exactly like an LMIII or an Aguilar TH500. The sound of a given amp is due to dozens of components, and hundreds of interactions among components, many of which are 'non linear'.

I've NEVER heard an amp of ANY type by one manufacturer sound like another amp of ANY type by another manufacturer, or even within manufacturer. No class D/SMPS amp sounds like another class D/SMPS amp... even amps that use the same ICE module.

Again, you are off the mark on this.

Several amp manufacturers have tried to duplicate the sound of an SVT with other formats. Tech 21 and TC are two just off the top of my head. Ampeg themselves have tried it. Close but no cigar. Same way with GK...I've played their little micros...they don't sound like their lead sled amps. They do sound closer to the GK lead sled sound than the Ampeg micros, but once again, close but no cigar.

If it could be done, someone would be doing it. And that's why YOU are off the mark and not me.

 

[KJung]

Several amp manufacturers have tried to duplicate the sound of an SVT with other formats. Tech 21 and TC are two just off the top of my head. Ampeg themselves have tried it. Close but no cigar. Same way with GK...I've played their little micros...they don't sound like their lead sled amps. They do sound closer to the GK lead sled sound than the Ampeg micros, but once again, close but no cigar.

If it could be done, someone would be doing it. And that's why YOU are off the mark and not me.

Again, you are making my point. No two integrated bass amps sound the same, regardless of topology. There are dozens of interacting components that make one amp sound the way it does. It is why different executions of all tube amps sound quite different. Per your example, a GK800RB sounds nothing like a GK700RB, even though they both use class H amps, etc., etc., etc., etc.

Constantly talking about the impact of 'big iron' or whatever is isolating one of a zillion inputs to an amp's performance, and is quite off the mark.

Again, no one has duplicated ANY amp of ANY topology EVER as far as I know. However (and this is another strong indication of how you are magnifying the importance of one of a zillion causal drivers), the closer you get to 'pure power amp' (i.e., a PA type power amp), the more similar they sound (assuming similar price/quality and actual wattage and THD, etc.).

Again, if someone digs an SVT, that is wonderful, and you are correct, they will need to buy an SVT. What you seem to not understand is that if someone digs a Carvin B2000, they will need to buy that also to get that exact performance. No magic involved. The performance and voicing of an integrated bass amp is a very complex mixture of many, many things, and no two are ever the same, nor could they be exactly duplicated.

Again, I have no dog in this hunt, other than to make sure people realize that lightweight amps (at this point in time) are in NO WAY a compromise. Yes, they all sound different, just like various all tube amps sound different. This idea of 'better and worse' based purely on amp topology is misleading to the average TBer who is shopping for a rig.

 

[B-string]

Why would anyone make their entire line sound the same? How would that ensure sales of different models and spread the appeal of the brand to different people?
The only company that tries to make "copies" that I know of is Behringer, look at how that makes that brand appear to people! To totally "copy" the signature sound of another brand or brand's "model" invokes hate and lawsuits. This would be "good business"?

 

[jasonbraatz]

To totally "copy" the signature sound of another brand or brand's "model" invokes hate and lawsuits. This would be "good business"?

It would, if you're the guys who make the Axe-FX.

 

[KJung]

Why would anyone make their entire line sound the same? How would that ensure sales of different models and spread the appeal of the brand to different people?
The only company that tries to make "copies" that I know of is Behringer, look at how that makes that brand appear to people! To totally "copy" the signature sound of another brand or brand's "model" invokes hate and lawsuits. This would be "good business"?

To Jimmy's point, since an amp like an SVT is considered a classic, I can see where Ampeg would attempt to get as close as they can to that iconic amp in a smaller, lighter, more cost effective format. As Jimmy says, 'close but no cigar'. I just think it is WAY more complicated that any one design component.

+1 though, more of a thought experiment outside a few classic amps like the SVT and maybe the early Acoustic stuff. Of course, I think much of the new stuff sounds much better than the old stuff, but that is just me. Many feel just the opposite.

 

[Chef]

The GK MB and RB series heads
-are supposed to sound different from each other-
and they do.
And it's not a small difference either.

Same way with GK...I've played their little micros...they don't sound like their lead sled amps. They do sound closer to the GK lead sled sound than the Ampeg micros, but once again, close but no cigar.

If it could be done, someone would be doing it. And that's why YOU are off the mark and not me.

 

[JimmyM]

Why would anyone make their entire line sound the same? How would that ensure sales of different models and spread the appeal of the brand to different people?
The only company that tries to make "copies" that I know of is Behringer, look at how that makes that brand appear to people! To totally "copy" the signature sound of another brand or brand's "model" invokes hate and lawsuits. This would be "good business"?

Seems to be working for Tech 21 and TC. And Behringer, for that matter.

 

[B-string]

I also remember someone saying his new Heritage sounds just like his '69.

The point is if you spend the money on the parts and engineering to "copy" a model, the end price will be close to the same. So would a buyer spend a few bucks more for the status of the original or save a few bucks to just have the copy. The company making the copy may not last a calendar year if they do it without copying the patented schematics. This is how a wise person would set up their business model? IMHO I see no gain or longevity in trying to carbon copy here unless it is a reissue of a model under your own brand name. Even then you will fight "the old ones are better" crowd.

 

[B-string]

The GK MB and RB series heads
-are supposed to sound different from each other-
and they do.
And it's not a small difference either.

Exactly, IIRC Gallien geared the original MicroBass series more to double bass than bass guitar and maintains the distinction to some extent still.

 

[B-string]

Seems to be working for Tech 21 and TC. And Behringer, for that matter.

So we are going from full amp typology copy to outboard modeling now?
I could ask the opinion on the "B" word but it is not necessary, just make a post or observe a post with that name attached

 

[BbbyBld]

If what you said was true, then how come nobody makes either a micro or traditional SS amp that sounds identical to the SVT, even after decades of amp manufacturers trying to?

Firstly, which SVT? You can have two vintage ones made the same year that will sound different. For example, I repaired a vintage one where a subtle mistake was made when it was built and it still worked for decades, but it would've sounded unique. You could have a tonal difference because two wires were closer together or farther apart. A piece of audio gear constructed that way (like most vintage amps) means you will have inconsistency. MI speaker specs are all over the map also. Also, when a good tech repairs an SVT, he will identify and fix certain design choices that caused problems with early ones (if it wasn't already reworked in the 70's). At that point, there is no right answer per say having to do with mods. I could theoretically duplicate an early 70's SVT that I might have laying around, and it may not sound like one of yours. Here at Peavey, we have worked with several artists who might say, make my lead channel sound like X-amp, but add this or that. We make them send us their X-amp because we have found that MOST of the time there's something up with it that makes it a unicorn amp. Jimmy, do all of your SVT's sound alike?

Maybe the manufacturers that COULD make a standard SS class AB or class D dwarf SVT have no interest and have never tried. There's a large number of bass players (and designers) who play other amps specifically because they DON'T respond like an SVT.

It's likely that most class D amps out there are far closer to the definition of an ideal power amp than the SVT power amp, which is kind of what this thread is about. It's obvious that you like the coloration of the SVT. I like the coloration a VB-2 gives me in one of my bands, but I use a class D combo amp in another band because I'm playing a different style. I essentially designed the VB-2 for myself, and my design decisions were based on achieving maximum stage presence from only 225 watts, which involves a hell of a lot of coloration. If I'm designing a head with a 700 watt class D amp, I'm going to make different design choices throughout the whole design because I have more power to work with. I'm not going to try to make my 700 watt class D amp sound exactly like the VB-2. You can love the EQ on an a 300 watt amp, but put 1000 watts behind that same EQ and you may hate it.

Finally, I not a believer in "transparent" power amps for all purposes. It's possible to make "colored" class D amps just like it's possible to make "transparent" tube amps. The Headliner power amp is class D and it was designed to feel like a tube power section.

 

[Vince Klortho]

Again, no one has duplicated ANY amp of ANY topology EVER as far as I know.

To the best of my knowledge, it has only happened in the stereo hi-fi world. Bob Carver duplicated the sounds of two different stereo amps by copying their transfer functions and they were indistinguishable from the originals in blind testing. He was not allowed to open the lids of the amps he was copying. He actually sold those amps too at a much lower cost than the originals.

He demonstrated that it is possible to do but these are the only cases I am aware of it ever happening.

 

[grendle]

would love to find one I liked the tone of to lighten my rig. Been through 4 class D power amps, they don't sound anything like the class a/b amps I have. I 've found the same as Jimmy with all of the class D heads I've played. Yep they make noise and stink and go boom but the tone doesn't compare to the led sleds. it's in the power section.

 

[Chef]

What?

Yep they make noise and stink and go boom

 

[grendle]

technical gearhead terms. meaning : they run ok and get the job done