1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  
    TalkBass.com has been uniting the low end since 1998.  Join us! :)

Why do I like the sound of AB amps better than Class D?

Discussion in 'Amps and Cabs [BG]' started by bdplaid, Apr 17, 2017.

  1. bdplaid

    bdplaid Supporting Member

    Aug 31, 2007
    Placebo? I don't think so.

    I got to thinking about this some time ago after I was blown away by the sound after sitting in on a jam where there was an Aguilar DB750. It inspired me to drag out my old AB power amps, notably a Crown XTi 4000 (I don't think I can even lift my Crest CA-9 anymore), and run various pres through them, and darned if I don't like the sound better.

    Why? It's deeper while being tight and articulate. Wattage is similar. Cabs are the same.

    I just read through a thread on TB about there being essentially no difference, tonally, between AB and D, but to me I think it sounds and feels different.

    I'm wondering about higher damping factor; my AB amps are >500, and to my non-electronically trained brain, that equates to better control over the speaker, hence tightness.

    So what am I hearing?
    Joebone and jjmf like this.
  2. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    What Class D amps were you comparing the Crown and Aguilar to?
  3. blubass


    Aug 3, 2007
    Modesto Ca
    Current: Blackstar, DR strings, Nady. Previous endorsements with: GK, Rotosound, Ernie Ball, Cleartone, EMG, Dean, Dava Picks, Rebel Straps, Dickies
    You're hearing the sound of different preamps through different power sections, and attributing the difference to the power amp.

    To give you an unbiased opinion, use an identical preamp with power amps that had the same or similar input sensitivity and power output. Have a friend help you do a blind test using settings you aren't controlling.
    figuredbass, lomo, Mosfed and 10 others like this.
  4. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    A double blind test would reveal whether you really can tell the difference. There are too many variables (EQ, cab, power, etc.) to make the blanket statements you have.
    SunnBass, lomo, Bob Lee (QSC) and 8 others like this.
  5. jjmf

    jjmf Supporting Member

    Oct 28, 2012
    Edmonton AB Canada
    I agree with the OP!
    - more weighted push behind the notes but still as fast and articulate in response...D class amps open up lots of other tonal pallet options with eq/filters/tube pre's/voicing/Distortion etc....but seems EVERY time I use a led sled I hear what your talking about !! It just seems to cut thru the mix better...or easier?

    including when using same pre-amp
  6. spiritbass

    spiritbass Supporting Member

    Jun 9, 2004
    Ashland, MO
    I don't have an explanation, but I know what I like...

    Since I don't move my gear around anymore, I will continue to enjoy my old school big iron and vacuum bottles (Reeves Custom 225 and Shaw B-150). :cool:
  7. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    I am perfectly willing to admit that my experiences with the lightweight amps could be coincidence. But I have yet to hear one I like nearly as much as I like my Walkabout or tube heads.

    Of course, preference could stem from tonal goals as well. One who is into more modern sounds anyway might actually prefer them.
  8. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    this is a very interesting response (at least to me) because the WA is a very tube-y sounding amp, but it has mosfet power - not tubes, so it is a hybrid approach vs the full on tube pre/tube power amps.

    I do get the draw of an all tube amp revved up with the tube power section adding that compression/grind thing it can do. I own and gig a WA as well as an all tube Fender Studio - along with the wonderful Demeter VTBP-M-800DJ. But, I also think that many players listen with their eyes, and are just pre-disposed to "hear" qualities in an all tube, or AB amp that might also be found in a hybrid amp where a well designed tube preamp (or even non-tube) is thoughtfully linked to ANY kind of power section can deliver a very similar (if not the same) experience.

    Don't get me wrong, I do love all tube amps into ceramic driver loaded cabs, but I also know from direct ears-on experience that the difference between these different types of amps is not as black/white as some would suggest.

    As Munji, Blubass and undoubtedly Agedhorse would agree, the only way to really honestly judge would be a blind listening test.

    on edit: I guess I would also ask the OP what class D amps he has tried (Aggie DB750, Crown and Crest power amps were already mentioned for AB). Perhaps he is comparing weak implementations of Class D with nearly legendary examples of Class AB amps ?
    Last edited: Apr 17, 2017
  9. Razman

    Razman Supporting Member

    Feb 10, 2005
    Orange Park, FL
    The difference, and I concur.

  10. bdplaid

    bdplaid Supporting Member

    Aug 31, 2007
    Mesa D800
    Markbass LM3 800
    MarkBass F500
    Rumble 500
    Acoustic B1000HD
    GK MB800
  11. Bodeanly

    Bodeanly Supporting Member

    Mar 20, 2015
    I agree that my class D amps don't sound as tight as my older, heavier stuff. However, once I get to the gig, soundcheck, and catch a glimpse of how it sounds FOH, I'm really glad I only had to make one trip from the car. So, until someone in the audience can tell the difference, I'm good.
  12. Doner Designs

    Doner Designs Steve Doner Gold Supporting Member

    Jun 2, 2012
    Metro Chicago Area
    Doner Designs is an alias for Steve Doner
    Not sure if I can hear the difference, but the fact that some say they can always causes me to hesitate on trading my Markbass 2x112 rig for something else (combo has the old Class AB LMIII in it).
  13. slagheap

    slagheap Supporting Member

    Dec 23, 2011
    oh, yes. there is a difference! i've been around a long time, been very active - played thru everything under the sun ( only slight exaggeration, ) and i'd go for big iron & ceramic magnets every time, if that stuff weighed 55 lbs. total, like my 2 H1203s + Mesa 800, including covers. big transformers make the notes more immediate, bigger, with more depth. i can play more gigs with the portable stuff, though. makes it soo easy...
    i'll never forget the first time i fired up a CA9. OH MY GOD! however, that set-up ( rack case, CA-9, tube pre, great old Eden 4 x 10, ) was pushing 200 lbs.
    Last edited: Apr 17, 2017
    Mario Lewis, /\/\3phist0 and bdplaid like this.
  14. sm49341


    May 12, 2013
    Where does this end? Seems odd to blame the power amp side, when the best speakers today arguably are the QSC k12's, snd their matching subs and they sound incredible. Even the amps for the mains FOH, everyone has gone lightweight class D for those amps. and those amps are still taking your A/B signal and cranking the lions share of your signal, is it not?
  15. BogeyBass


    Sep 14, 2010
    yes a blind listening test will work great. i agree
    here is the sound of amp A going through a ampeg 810 for 2 hours,
    here is the sound of amp B going through a Ampeg 810 for 1/2 an hour.
    whats up with amp B why not 2 hours? oh it shut down. oh ok i think amp A sounds better. yeah me too what was amp A oh thats a weezy little 100 watt tube amp. oh cool. what was amp B ? oh that was a high power 500 watt class D. oh ok. its really efficient in fact its so efficient it deciding to shut off to conserve energy lol

    now for our next blind test
    Razman likes this.
  16. Brian Silcock

    Brian Silcock

    Apr 4, 2017
    I think it really is a personal preference
    I, like most here, have played through many amps
    Some really garbage AB amps that sounded horible
    But there are too many factors to consider
    If you are happy with your sound use what you like
    Really the tone come from you first. And what enhances YOUR sound is what is best
    And some of us are old and do not want to carry a 100 LB+ amp anymore so class D is the best end of story !!
    Lvjoebass likes this.
  17. monsterthompson

    monsterthompson The Eighth Note Wonder Of The World Supporting Member

    Nov 25, 2008

    In the history of TB, there has never been a satisfying reply to this type of question. It's usually just a thread with two responses:
    1 - Topology doesn't have a sound.
    2 - Anecdotal responses about tubes and iron being personal favorites, yet no explanation given regarding why those things do or might sound different.
  18. Al Kraft

    Al Kraft Supporting Member

    May 2, 2016
    Northern Virginia
    I think a properly designed double blind test that fully exercises all of an amp's characteristics/capabilities (recovery, transients, damping, etc.) is the only way to tell for sure which one sounds better. However, I'm guessing that in some cases there won't be a statistically significant/valid outcome in terms of people correctly identifying Class D or A/B consistently.

    I have a fondness for the voicing I associate with heavyweight tube, hybrid and solid state amps. I actually hear some of that in some class D products, but still own some of the heavy stuff as well. FWIW I have two guiding questions that always pop into my head when this topic comes up. First is how I would vote if the test included an Ampeg B2R (which I owned years ago) against my TH500 - most who have heard both heads would likely guess the Ampeg was the "lesser contender and therefore class D". I also ask myself why the big commercial sub-woofers are mostly class D powered if "lightweight amps" can't cut it when it comes to big, full, hard hitting bass.

    I tend to think that "the difference between amps I clearly hear" is often more a result of design choices/design execution rather than class of amplifier. I can think of a lot of class A/B heads that if compared would cause me to conclude that one was class D and the other class A/B. I'm not saying there isn't a difference, because every design choice brings benefits and baggage, but as with 99.9999% pure copper boutique speaker cables versus the "yeah, it's copper" store brand, that difference may not be quite as significant as we would have expected. YMMV! :)
    Plutonium244 and Groove Doctor like this.
  19. socialleper

    socialleper Bringer of doom and top shelf beer Supporting Member

    May 31, 2009
    Canyon Country, CA
    I watched a video on class-D amps, and it does seem like there is a lot of "stuff" happening between the instrument and what comes out the other end. That is probably why there was so much difference in the earliest days of class-D. My person, biased, non-scientific opinion is that that they are getting better and sounding more "natural" with every generation. The Mesa D-800 has received the accolades it has because of its rich, meaty tones. When I did an A/B with one and a Shuttle 9.0, both flat, I heard a difference immediately. Low-mids are everything.
    I would also hazard a guess that preferences in EQ trends change often. An older amp might have a different EQ flavor built in that some people find more pleasant. Then it comes down to a matter of personal taste.
    Finally, people tend to like things they are familiar with. Whether a class A/B or D is better is subjective to what the listener likes. People always like familiarity.
  20. jumbodbassman

    jumbodbassman Supporting Member

    Dec 28, 2009
    Stuck in traffic -NY & CT
    Born Again Tubey
    Because they sound better IMHO
    birminghambass likes this.