Are Class D amps really 5 times less powerful than A/B?

[Rich Fiscus]

I was sure this would be closed by now.
I'm taking my zeros and ones and going home!

The joke's on you. They won't do you any good unless you know where I've hidden all the ANDs ORs and NOTs.

 

[bdplaid]

Back on topic, I wanted to mention that several years ago, I was on the "Class AB is better" train.

I had a Crest CA-9 that I loved and was going to be buried with me. But out of curiosity, I connected whatever class D amp I was using at the time, to whatever cab I was using at the time; then I ran the preamp out of that same amp and fed it to the CA-9, which was connected to the same speaker. I couldn't tell any meaningful difference. I imagine if I had wired up my old stereo stage rig with all the bells and whistles it might have made a diff, but really, no. I instantly lost 48 lbs from my rig.

Class D is the real deal.

EDIT: I just discovered that the CA-9 is Class H. Also, no mention in the specs about HPF.

 

[Wasnex]

At the risk of jumping into a thread that I really should stay away from...

Class D is most likely reproducing the lows perfectly. If your class D is clipping then you would know about it... In fact its your old A/B tube amp that's messing up the lows. The tube amp is pushing into clipping/compression which is gently distorting those low frequencies and adding in higher frequencies that shouldn't be there.

Thing is - you (quite reasonably) LIKE those extra frequencies - they're the "heft" and "thump" you talk about.That those are missing from the Class D is theoretically a good thing. However once you get into preference then its up to you what you like.

If you want that "heft" from the class D then you'll need to introduce that at the pre-amp stage, and then let the Class D do its job and make it louder.

That sounds reasonable, except I don't generally run any of my high-powered rigs at levels where they are producing significant levels of distortion on the outputs.


The die-hard, all-tube crowd tends to prefer pushing the output section of their(s) amp to a certain saturation level, and I think the process you describe is the reason.

So while I agree the process you are describing occurs, the amps I am thinking of have slam and heft long before they are pushed.

Trace Elliot V6. This is considered a 400W and I think it possibly has the best lows of any of my tube amps.

Reeves 400 is also obviously considered a 400W amp. It probably has the most extended lows of any tube amp in my collection, but the energy is focused a bit too low to produce the slam and heft of the V6. However, if I push this amp fairly hard, the tone and feel does transition exactly as you describe.

On the solid state side, I would say my Mesa Titan, Genz Benz GBE1200, and Jule Monique 700 have the most heft and slam. I believe my Mesa M9 has the most extended lows, but it takes a lot of fiddling with the tone controls to get the same degree of heft and slam as the three amps above. All of these amps are hybrids. The GBE1200 has a FET channel and it still has plenty of heft and slam even when the signal path is 100% solid state.

 

[bdplaid]

I now have a question about Class D and what some people think they are hearing: High pass filters. I've noted that several amps have them built in; not adjustable HPFs, but internal to the amp. For example, the Quilter is HPf'ed at 35Hz I believe. I wonder if this is making a diff as to what people think they are hearing?

 

[DWBass]

This thread...........

 

[DJ Bebop]

This thread...........

I know huh?
Human, please.

 

[agedhorse]

I now have a question about Class D and what some people think they are hearing: High pass filters. I've noted that several amps have them built in; not adjustable HPFs, but internal to the amp. For example, the Quilter is HPf'ed at 35Hz I believe. I wonder if this is making a diff as to what people think they are hearing?

Maybe, though I included HPFs on all of my class AB amps as well.

 

[mbell75]

Back on topic, I wanted to mention that several years ago, I was on the "Class AB is better" train.

I had a Crest CA-9 that I loved and was going to be buried with me. But out of curiosity, I connected whatever class D amp I was using at the time, to whatever cab I was using at the time; then I ran the preamp out of that same amp and fed it to the CA-9, which was connected to the same speaker. I couldn't tell any meaningful difference. I imagine if I had wired up my old stereo stage rig with all the bells and whistles it might have made a diff, but really, no. I instantly lost 48 lbs from my rig.

Class D is the real deal.

EDIT: I just discovered that the CA-9 is Class H. Also, no mention in the specs about HPF.

Alli know is I've gotten rid of a Fender Rumble amp and just recently, an Ampeg RB amp. They are pretty sterile, boring and sound nothing like their tube big brothers IMO. Meanwhile, I've just recently tried a Boss Katana 210 and an Orange Crush 100. Both sounded significantly better than the Fender and Ampeg IMO. I know the Boss is A/B and I'm pretty sure the Orange is too but not sure, and both use analog everything from what I've read. So I guess I'm just not a Class D guy…

 

[Stan_da_man]

Most every high end bass amp uses an A/B (or B I think) power section rather than Class D. Why is that? Just a coincidence?

Because it's all valve?

 

[Texican]

Alli know is I've gotten rid of a Fender Rumble amp and just recently, an Ampeg RB amp. They are pretty sterile, boring and sound nothing like their tube big brothers IMO. Meanwhile, I've just recently tried a Boss Katana 210 and an Orange Crush 100. Both sounded significantly better than the Fender and Ampeg IMO. I know the Boss is A/B and I'm pretty sure the Orange is too but not sure, and both use analog everything from what I've read. So I guess I'm just not a Class D guy…

Sterile is not a word I would use to describe any amp that has a characteristic baked in tone that's nowhere near FRFR… like Fender and Ampeg. Their budget conscious class D offerings may not sound complex, but they definitely aren't sterile. At least not the way I hear "sterile" as an aural description.

 

[seamonkey]

Amp makers who advertise "Class-D" shouldn't bother.
There are many variants on Class-D they are missing out on what makes their own special.

Nobody can hear class anyhow. Skip the "Class-D" and just marketing: "Light and Cool as a Cloud", "Incomparable Loudness", "Innovation exceeds Class"
And build them like car engines where if you open them up you see shrouds molded plastic and no real parts.

 

[mbell75]

Sterile is not a word I would use to describe any amp that has a characteristic baked in tone that's nowhere near FRFR… like Fender and Ampeg. Their budget conscious class D offerings may not sound complex, but they definitely aren't sterile. At least not the way I hear "sterile" as an aural description.

Ok, well lets put it this way. The Rumble sounds nothing like the classic Fender bass tone I think of, which is a BF Bassman. The Rocket Bass sounds nothing like the classic Ampeg tone I think of, which is an old school SVT. Actually, whatever default preset Boss has dialed into the last custom setting on the Katana amps sounds more like an old school Ampeg tone than Ive heard from actual Ampeg combo amps in decades. Not surprising though, Ampeg hasn't sounded like Ampeg since before St. Louis took over in the mid 80s and the amps under LOUD were awful. They should have just retired the name to be honest. But thats another story for another day.

 

[bdplaid]

Alli know is I've gotten rid of a Fender Rumble amp and just recently, an Ampeg RB amp. They are pretty sterile, boring and sound nothing like their tube big brothers IMO. Meanwhile, I've just recently tried a Boss Katana 210 and an Orange Crush 100. Both sounded significantly better than the Fender and Ampeg IMO. I know the Boss is A/B and I'm pretty sure the Orange is too but not sure, and both use analog everything from what I've read. So I guess I'm just not a Class D guy…

Funny, now the marketing is "analogue" rather than "tube." Because the orange crush is all solid state, usually a NoNo for guitar.

We ought to make a list of the marketing words used to mislead customers.

 

[mbell75]

Funny, now the marketing is "analogue" rather than "tube." Because the orange crush is all solid state, usually a NoNo for guitar.

We ought to make a list of the marketing words used to mislead customers.

Im also a guitar player and you are right, but Orange is an exception. Their SS Crush Pro 120 guitar amp is fantastic. One of the best SS guitar amps ever made IMO. I owned one at the same time I owned a Rockerverb 50 MKIII, and the difference was very slight and really only noticeable when you cranked both amps way too loud. Gigged the Crush several times and it sounded great.

 

[bdplaid]

I recall reading an article saying class D is most appropriate for low cost, low frequency audio applications. So that implies it's not a good fit for guitar. Having said that, every guitarist I've ever worked with sans 2 was adamant about using tube amps.

Is good, whatever blows up everyone's skirt, I say.

 

[agedhorse]

Alli know is I've gotten rid of a Fender Rumble amp and just recently, an Ampeg RB amp. They are pretty sterile, boring and sound nothing like their tube big brothers IMO. Meanwhile, I've just recently tried a Boss Katana 210 and an Orange Crush 100. Both sounded significantly better than the Fender and Ampeg IMO. I know the Boss is A/B and I'm pretty sure the Orange is too but not sure, and both use analog everything from what I've read. So I guess I'm just not a Class D guy…

Have you considered that the voicings of those 4 amps are nothing alike, completely independent of the power amp? You are making conclusions by comparing apples to oranges (literally), to lemons to kiwi... yest they are all fruit but all very different.

Ok, well lets put it this way. The Rumble sounds nothing like the classic Fender bass tone I think of, which is a BF Bassman. The Rocket Bass sounds nothing like the classic Ampeg tone I think of, which is an old school SVT. Actually, whatever default preset Boss has dialed into the last custom setting on the Katana amps sounds more like an old school Ampeg tone than Ive heard from actual Ampeg combo amps in decades. Not surprising though, Ampeg hasn't sounded like Ampeg since before St. Louis took over in the mid 80s and the amps under LOUD were awful. They should have just retired the name to be honest. But thats another story for another day.

Of course the Rumble doesn't sound like a Bassman... it's a Rumble which is their more modern voicing. There are Bassman models (500 and 800) that have the more classic voicing.

Of course the Rocket Bass sounds nothing like the SVT, it's a reissue and re-visiting of their classic Rocket bass amps which are voiced very different from the SVT. Ampeg amp tone didn't change much during the Loud days, other than different models like say the BA type series. Loud had other challenges, but different from what you claim.

I recall reading an article saying class D is most appropriate for low cost, low frequency audio applications. So that implies it's not a good fit for guitar. Having said that, every guitarist I've ever worked with sans 2 was adamant about using tube amps.

Is good, whatever blows up everyone's skirt, I say.

Class D can be GREAT for guitar if the preamp and signal management is well designed. The easiest example is the new Fender Tone Master series, I've heard them and they are very, very convincing.

In the old days (say 20+ years ago), they might not have been the best choice however.

 

[chris_b]

I haven't used a tube amp in 20 years. All the guitarists I play with are still using Fender tube combos. . . . but there are a few who are now looking at SS and D class amps.

The revolution is coming.

They just needed better sounding tubeless amps.

 

[mbell75]

Have you considered that the voicings of those 4 amps are nothing alike, completely independent of the power amp? You are making conclusions by comparing apples to oranges (literally), to lemons to kiwi... yest they are all fruit but all very different.



Of course the Rumble doesn't sound like a Bassman... it's a Rumble which is their more modern voicing. There are Bassman models (500 and 800) that have the more classic voicing.

Of course the Rocket Bass sounds nothing like the SVT, it's a reissue and re-visiting of their classic Rocket bass amps which are voiced very different from the SVT. Ampeg amp tone didn't change much during the Loud days, other than different models like say the BA type series. Loud had other challenges, but different from what you claim.



Class D can be GREAT for guitar if the preamp and signal management is well designed. The easiest example is the new Fender Tone Master series, I've heard them and they are very, very convincing.

In the old days (say 20+ years ago), they might not have been the best choice however.

Good points but I just find it a bit odd that although I love Ampeg and Fender bass tones, I dont like the sound of their Class D amps at all. Meanwhile, I really like the Boss and Orange tones which are not Class D.

I agree about the Fender Tone Master amps. They are fantastic and sound REALLY close to the tube amps. That is a great example of Class D done right IMO.

 

[Texican]

Good points but I just find it a bit odd that although I love Ampeg and Fender bass tones, I dont like the sound of their Class D amps at all. Meanwhile, I really like the Boss and Orange tones which are not Class D.

I agree about the Fender Tone Master amps. They are fantastic and sound REALLY close to the tube amps. That is a great example of Class D done right IMO.

It seems that you like specific Fender and ampeg tones, and not other specific Fender and ampeg tones. Aged Horse asked if you had considered that the preamps were voiced differently on those specific amps, independent of their power sections… And it seems that you did not, even after he raised the question. You are still seemingly convinced that having a class D power section will make an amp that was otherwise destined to sound like a Bassman or SVT sound like garbage. That's your prerogative, but at a certain point when you have 200 different strangers disagreeing with you and telling you the exact same thing, the discussion kind of reaches a stalemate. It took like five pages for people to convince you that class D amps aren't digital, and yet here we are still. I don't mean any disrespect to you, but sometimes it's just OK to be wrong about something. We all do it… Hell, aged horse literally misused the word literally while replying to you, and he is never wrong!

 

[agedhorse]

Hell, aged horse literally misused the word literally while replying to you, and he is never wrong!

I was referring to orange the fruit versus orange the amp, hence literally