Class D amps weaker than A/B?

Discussion in 'Amps and Cabs [BG]' started by baxter_x, Feb 27, 2018.

  1. baxter_x


    Nov 27, 2013
    ....yes a class D thread again ;)

    A friend of mine, bassist too, keeps telling me class D amps lack something. Compared to class A/B amps, he feels it's a bit weak or lacks of something.
    He has owned the following amps: Tecamp Puma 1000 , Epifani u502 and performer, Markbass.
    He feels it's nice alone, but in a live/stage mix, he can't hear himself or it's too aggressive. In the end it's never the right thing.

    I don't have much experience with class D amps expect trying them in stores on rehearsing with a Mark Bass amp sometimes. But I strongly advised him to try the Mesa D800 that really impressed me tone wise when I compared it against other famous class D amps (Aguilar, GK, Mark bass).

    Do you guys feel the same, have you experienced a difference in the presence of a class D or A/B amp?
    To me, the EQ should make the difference, not the power section. but I might be wrong.
    murphy likes this.
  2. They lack weight. Nothing else.

    I have many amps of all flavors from tube led sleds to A/B SS amps to class d mini amps.

    The power makes no difference. It’s the flavor of the preamp that makes the biggest difference.

    Those that think differently are not listening with just their ears
    Hasting, Riss, Sascha Erni and 54 others like this.
  3. kpc


    Apr 6, 2011
    I have both and Class D doesn't lack anything other then weight. JMTC
  4. Robroy

    Robroy Guest

    Jun 21, 2006
    This will explain the difference people are hearing between a/b and D:

    Psychoacoustics - Wikipedia

    This affects how people think they hear differences between amps, guitar body material, CD vs Vinyl recordings, you name it.

    Only double blind tests are really trustworthy, and many condemn them when they don't like what they reveal. :)
  5. Tube power amp power. . to me. ... is different... not better or worse.. but... different.
    In my 40 yrs of playing live ..I own trad solid state , all tube and class D... like em all. . I find they all have good and a tiny bit of summink else ...
  6. baxter_x


    Nov 27, 2013
    Totally agree with this! That's the reason why I always used MY ears and not the common rumor/consensus to choose my stuffs. I remember when I rented last year an SVT II Pro as it's one of the "best tube amps ever made with the SVT-CL."
    I played it, liked it, but to me was not worth carrying that damn heavy thing. I've also heard many times a "tube amp can't do high fi sound". Well, I could produce super clean slap tones out of this very tube amp.
  7. The class of the amplifier by itself is not the primary factor.
    This all has to do with how we perceive different harmonics.

    You can implement Class A/B as tube or solid state.
    The first solid state Class A/B amps used N or P channel discrete transistors.
    The class designations A through C are based on the conduction angles of the amplifying device, not what type of device is used to amplify the signal.

    Class D can be implemented as discrete N or P channel transistors though it more commonly uses MOSFETS.
    It could even be implemented with tubes, though it would be highly impractical.

    To say that one class of amplifier is better, or weaker, or whatever you want to attribute to it, than another, based solely on the class of the amplifier, would be an incorrect statement.
    If someone is comparing a tube amp to a Class D amp and assumes that tube always means A/B then they are comparing apples to oranges. The correct comparison would be tube vs solid state.

    Tube amps treat harmonics differently than solid state amps. And it's the harmonics that give us the perception that one type of amp may be better sounding or louder. It depends on how you play. In a clean amp, there won't be much difference. But if you use a lot of overdrive (generate lots of harmonics) you may hear differences in how the different amps sound because of how each type generates harmonics, handles distortion.

    As far as power is concerned, 500 watts, is 500 watts, is 500 watts. It doesn't matter if it's so called "tube watts" or not. By measurement a 500 watt tube amp is the same as a 500 watt SS amp. What does matter is how an amp sounds to you with the way you play. When you compare the rated power output of two amps, be sure that they are both running the same amount of distortion. Added distortion can make an amp sound louder.

    A 500 watt amp operating at 10% distortion (heavy overdrive) will be louder than a 500 watt amp at 1% distortion (clean). Furthermore if the harmonic content of that distortion is more pleasing to you you, it will seem to you to be a better amp.

    If you like the sound of tube amps better than solid state, by all means play tube amps. You like what you like and ther's no denying that. If a solid state amp is the right tool for you, then that's your go to amp. But let's try to get past this "A/B is louder, better, more powerful" because it is A/B.
    Last edited: Feb 27, 2018
  8. JRA

    JRA my words = opinion Gold Supporting Member

    the best way! :thumbsup:
    Mugre, baxter_x and Old Garage-Bander like this.
  9. baxter_x


    Nov 27, 2013
    Tell me more about this % of distortion. Is it the distortion from the preamp driving the power section or is the the distortion of the power section?
  10. bucephylus

    bucephylus Supporting Member

    Aug 18, 2002
    Central Ohio

    Expert opinion derived from two 1st gen Class D micros and one 2nd gen. This is where the problem is. You get a new technology, and people make up their minds based on the first baby steps, don’t bother them with the facts.

    I know life is simpler when you compartmentalize information like that; but, as with life, nothing is that simple. Which makes your friend honestly ignorant.

    First, the Class D power modules for micro amp footprints were only designed with the bass guitar as a specification in the latest generation micros. That is one reason that users of latest gen bass micros are generally walking around with $#17 eating grins on their faces.

    Second, FOH Power Amps switched over to larger format Class D quite a while ago. Class D is literally running most of the big shows now. No one is complaining about those systems missing anything. I happened to haul my big rig out yesterday; because I am planning to consolidate the two racks to downsize the bigger of the two. The power amp I am using is a Crest ProLite 3.0, powering two Bergantino 212’s. That Class D will pretty much take your head off with FULL range bass tone. It ain’t missing anything.

    Class D is relatively new-ish. There continues to be a development curve. Getting into mud slinging based on the Class alone is a relatively uninformed position.
  11. Robroy

    Robroy Guest

    Jun 21, 2006
    Completely agree.

    For me, class D is to sound amplification today what LED is to flashlights today. I have two Crown Class D for my PA and one powered by a BBE BMax pre for my bass rig. Loading in and out became significantly easier.
  12. baxter_x


    Nov 27, 2013
    Nice example.

    Great analogy! ;)
    Bassdirty, Crockettnj and teemuk like this.
  13. bucephylus

    bucephylus Supporting Member

    Aug 18, 2002
    Central Ohio
    Another comment about the Puma comes to mind.

    I have a VERY high regard for the Tech/Tecamp products (they changed their name, for those who may not know). I still have two of the early Tech Basslines 212’s, which interestingly were used as a model for the Schroeder compact 212’s; and those cabs are downright monsters.

    But, in that same timeframe, Tech produced an AB head, which was powerful; but, it was the very definition of sterile. The engineers at Tech have traditionally produced nails on chalkboard clean amplifiers; which some players really like. Nothing wrong with that. I merely mention that for perspective on the Tecamp 1000. Great amp, if that’s your sound. But, the tone profile is more rooted in the engineering philosophy than the output Class. Anyone who thinks AB is inherently “warmer” than Class D and cites the Tecamp as an example needs to go track down one of the early Tech Basslines AB amps, and play through one of those.
  14. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
    It's from wherever the designer chooses, and however the designer chooses. There are many ways to skin this particular cat.
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  15. baxter_x


    Nov 27, 2013
    So it can be the preamp driving the power section or the power section itself? It's up to the maker?
  16. jwindham


    Sep 17, 2006
    In my experience with both AB & D versions of the Markbass LMII/III, I found the Class D LMIII version did not quite feel as taught/firm under my own fingers vs the older AB LMII/IIIs. My guess is its likely something to do with how the different power sections 'control' the speakers. I especially noticed that the class D LMIII ran out of steam rather quickly when turning up the volume powering an 8ohm cab. However, at 4ohms I found the LMIII to have plenty of power, though it still had a slightly "looser" feel to the sound vs the class AB models. In theory, the preamps of both AB/D LMII/IIIs are the same.

    That said, I think the Class D LMIII may actually go a bit "louder" (but perhaps with less definition) than the AB LMII/III at 4 ohms. It seems that is where the Class D LMIII is at its strongest, with the most headroom. Just my observations...I still prefer the older AB LMII/III, as the sound comes across as a bit thicker/denser, less wide/clinical, to my ears. Also note, my observations are very specific to the LMII/III series, and the implementation of Class D in this particular model. Markbass also designs their own power modules unique to the industry standard ICE modules. Of course, any one amp, of any amplifier class, should be evaluated based on its own design merits & user experience. For example, the 800 watt module used in the current LMT800 seems to have quite a bit more clean headroom than the current LMIII at 8ohms.

    Ive played many different lead sled and micro amps, and feel design/implementation can make a world of difference. Heavier does not always equal louder, smoother, or more defined bass either. Ive played a few "lead sleds" that didn't quite deliver upon expectation. However, the best of the AB amps Ive played certainly had plenty of headroom, presence, and definition that is very compelling. Overall, modern Class D modules- and more importantly, how they are implemented- continue to improve to the benefit of many bass players. But, I think its important to choose amps based on one's own ears and experience, rather than just looking at the specs.
    AlexanderB, Artman, Zbysek and 4 others like this.
  17. jaymelewis


    Jan 6, 2010
    Fillmore, CA
    I'd agree with this - the preamp stage is by far the most important for getting different tones.
  18. JeezyMcNuggles

    JeezyMcNuggles Supporting Member

    Feb 23, 2018
    Santa Maria, CA
    I suck, but nobody really notices
    Does his amp have tubes in it? My tube pre class D sounds amazing. Huge tone and enough power for anything on the market.
    teemuk likes this.
  19. el murdoque

    el murdoque

    Mar 10, 2013
    OP, you and your friend should rig up a setup that allows you to A/B a class-D vs. a class A/B amp.
    Just use the same preamp and plug into the FX return. Set both poweramps have exactly the same volume.

    Do a double blind test.
    One of you just might feel stupid afterwards.
    lomo, AlexanderB, RickyWoo and 2 others like this.
  20. baxter_x


    Nov 27, 2013
    That would be a great test.