Should amplifier classes be matched?

June 5, 2022
 by Paul McGowan

9 comments on “Should amplifier classes be matched?”

  1. I don’t contradict your essence, but what I experienced is, that you only get the full high biased class A advantage (e.g. in resolution), when you use it in the pre AND power amp stage. Other synergies may happen well, but you never get class A strengths as you could then. I would even say, you get little of it only then.

  2. It’s not so much that all speakers are deficient as much as all rooms are deficient and what kind of speaker designs are least negatively effected by the room.

    1. Some people may call me a nut, some may even call me stupid for the statement that I’m about to make.
      But also, there’s a lot of sonic truth in it.
      A really good class AB tube power amp right along with a really good class AB tube preamp, makes musical magic.
      That is, to my ears they do.
      The same thing is also true about a class A tube power amp, and a class A tube preamp.
      So, yes, to get the absolute best sound in to my ears, I’m gonna match the power amp and preamps up to each other.
      And I will also do the same thing with the audio sources where ever and when I can too.

      1. Like Paul said most if not all preamplifiers are class A. Preamplifiers don’t need high current like an amplifier does. If you’re only going to consider a class A amplifier because the preamplifier is class A and you want to match that then you’re going to have to sacrifice power because most class A amplifiers don’t provide much power and that’s not good for inefficient speakers unless you are prepared to dish out a lot of money for a high powered class A amplifier like found in Pass Lab mono block amplifiers.

        Most class A tube amplifiers don’t have much power output or provide the current needed into speakers that drop to 4 ohms or lower so the choice of your speakers are limited and you won’t be able to buy the best speakers for your money.

        Also I don’t see the point in tubes unless everything in the signal path is tube including tube preamplifiers, tube amplifiers including both the input and the output stages, tube DAC’s, tube tuners, tube phono preamplifiers and even tubes in electronic musical instruments, microphones and mixers to make the recordings. There’s going to be non tube processing somewhere along the line messing up the so called tube sound unless the tube itself is altering the sound of something that was originally processed without tubes. To me that would be distortion.

        Paul say’s he only like tubes in the input stage of an amplifier and not the output stage. Is it impossible to make a great tube output stage or does that have to do with cost to make such a device impractical? It’s much more cost effective to have Bipolar or MOSFETS in the output stage that can drive any speakers on the market.

        1. I found that the Onkyo A-9755 ‘D’ class amp that I owned for 12 years worked extremely well, much better than the previous Luxman C-120/M-120A pre/power combo, with my old Celestions…made the bass more punchy & ‘live’ & the treble more detailed & ‘present’. However more ‘modern’ loudspeakers seem to sound better with class ‘A’ or ‘AB’ amps…to my ears & from my limited experience on this topic.

        2. Vacuum tubes potentially offer better linearity and a benign clipping behavior compared to a classic transistor. However there are modern transistor designs and as long as you have enough wattage for fulfilling the requirement of your loudspeakers there should be no clipping at all. And the best: there are great class D power amps out there today. And for those who want to improve bad recordings or bad mixes, they can always add typical colorations provided by some vacuum tube designs. I prefer powerful DSPs for the final optimizations in my most individual listening room. 🙂

      2. My experience is similar to yours, John. Tube integrated, tube DAC, and tube phono preamp. Together, they give the warmth and dimensionality that works for me. It also makes the room nice and warm in winter. That’s not a plus in the desert summer though!

  3. More important (bigger picture) is ‘whole system matching’.
    I’m sure that a tube pre & a ‘D’ class power combo will
    work (sound) fantastic in some home-audio systems.

    ‘So much gear (combinations to explore); so little time (& money)’ 😉

  4. I always find these discussions of tube vs. solid state and vinyl vs. digital most interesting by informed audiophiles. We all have our preferences usually based on long experiences . I happily abandoned tube equipment in the early 70’s and vinyl in the 90’s never to return. I looked on both as gradual degradation of sonics.
    With hi rez digital and excellent solid state now available, it’s so easy to find a combination that provides that magic. I did with a Pass preamp and a Bryston cubed amp. Room heater,clipping, sonics compromise ? Not in my audio world.

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