@larry5729
answers to your why question:
- heat
- efficiency
- weight
- cost
- heat
- heat
answers to your why question:
- heat
- efficiency
- weight
- cost
- heat
- heat
High end Class D amps?
Just an observation and a question. Are there 'high end' Class D amps out there that are just as good as Class A, A/B amps? I realize that's a sensitive question to some and I mean no disrespect---but whenever I see others' hifi systems on social media, all of the amps are A or A/B. There's always Pass, McIntosh, Moon, Luxman, Accuphase, etc. Where are the Class Ds? For folks out there that want more power for less efficient speakers and can't afford the uber expensive Class As, A/Bs, what is there to choose from that's close to those brands? Thanks
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- 510 posts total
In general, solid-state (ss) amps reproduce deep bass frequencies better than tube amps. A good indicator of an amp's bass reproducing ability is its Damping Factor, which basically measures its ability to control, or start and stop, the bass driver. The higher the number the better its control. Class D amps usually have much higher damping factors than the other amp types; class D amps can be rated in the low thousands, class A and AB are typically rated in the low hundreds and tube amps even lower.There really aren't any speakers that need more than 20:1 in a damping factor and some need considerably less. On top of that, traditional solid state amps actually have enough feedback at bass frequencies to do the job (whereas they usually don't at high frequencies, which is why they are often bright and harsh). I always thought pure class A amplification was most ideal. So why manufacture Class D amps?Class A is all about the output section- keeping its distortion as low as possible and its quite effective. But this says nothing about the input section and driver circuitry, and the output section is still going to make some distortion (just less than if the same circuit were class AB or B). Class D uses a different means (switching) to make power, and so does not make distortion in the same way. There are basically two means that the amp produces distortion- the first is how accurate the encoding scheme is. The second is caused by the fact that the output transistors take a finite period of time to switch on and off and so to prevent damage to them, a bit of waiting is done to allow one device to shut off before the other is turned on. Otherwise current can shoot through both devices, heating them up quickly towards failure. This waiting time is called 'dead time' and contributes to distortion. The distortion signature is different from traditional solid state and does not tend to be bright. Instead it tends to have more lower harmonics like tube amps, and not surprisingly can sound a lot like a tube amp, except when the amplifier is overloaded. Certainly the reduced amount of heat is an incentive- this is the main argument against both tube amplifiers and class A amps and especially class A tube amps :) |
I replaced Marantz MA-500 monoblocks with Nord Hypex NC500 monoblocks. The Hypex amps are awesome. The Marantz are terrific, and I was happy, but the Hypex took it to another level. Had friends come over and listen to both. Speakers are Philharmonic Audio Phil-3 with two SVS SB2000 subs, one for each channel, and preamp is Cambridge Audio A308cr and player is Rega Apollo. Outboard NAD M51 DAC. In my own experience can’t beat these new generation Class D amps. Dead silent and ample transient power. Now I am building myself ICEpower 1200As1 based monoblocks. Had a custom case made by Ghent Audio, who did a great job. More power can’t hurt. Considered the Benchmark AHB2, which had terrific reviews and specs. Almost bought them, but I suspected more power is better. The Benchmark noise floor is measured a bit lower, but we are in extremely low noise territory to begin with with these amps. Some links for anyone interested: Benchmark AHB2: https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-benchmark-ahb2... Nord Hypex NC500: https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-nord-one-nc500... Hypex NC2K: https://www.audiosciencereview.com/forum/index.php?threads/apollon-hypex-nc2k-monoblock-amplifier-re... ICEpower 1200AS2: https://www.audiosciencereview.com/forum/index.php?threads/apollon-as1200-review-and-teardown.9373/ Purifi 1ET400A: https://www.audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-purifi-1et400a... Benchmark has been measured to have the lowest distortion/noise. However, we are looking at levels generally below .005% I, for one, am not going back. These amps are terribly efficient. I previously had Bryston amps that were simply great, but that was 20 years ago. PS - I have a separate HT system where I use a $400 Crown amp to drive subwoofers (18 inch Dayton), I built. Clearly, others have different experiences and views. I have a cousin with the exact same speakers (we purchased them together), but he swears by his Audio Research tube system and I tell him he is wasting his money, and if he wants a tube characteristic, the Schiit Freya+ is difficult to beat, though his AR reference preamplifier is simply terrific. Have fun! |
- 510 posts total