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Anyone compared high end Class D power amps?

Discussion in 'audio' started by Thetiminator, Jan 7, 2020.

  1. I agree Class D cannot compete within an apples for apples THD+N test.

    Example, my A/B amp:
    Distortion factor (THD+N, 10 watts @ 4 ohms): 0.0062 %
    IM distortions SMPTE (5 watts @ 4 ohms): 0.0075 %
    IM distortions CCIF (5 watts @ 4 ohms): 0.0008%
    Upper limit frequency (-3dB / 10 W @ 4 ohms): > 185 kHz
    Damping factor: 1000 at 100 Hz
    Bandwidth: 1 – 500,000 Hz
    SNR:> 103dB @ 1kHz

    ACI-600 Class D amp:
    THD+N: <0.01% 1kHz A-Weighted
    SNR: >70dB A-Weighted
    THD+N: 0.003%, 1kHz
    Dynamic Range: 110dB, A-weighted 20Hz-20kHz
    Frequency Response: -3 dB 0.5Hz-50kHz, all loads
    Damping factor: >500
  2. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    It shows the expected lack of audible differences ie fractions of a dB and at 10-20Khz. As so easily predicted from inductance of cables. I agree with Villchur. And P. J Walker, and D. Self and many others who say they make no difference.

    Anyway we are getting off topic and if any subject has done to death already it's this one!

    Many such reports exist. They usually show things happening in the MHz range, well above even bats hearing.
  3. CJ14

    CJ14 Retired

    Cables and cables let open a new page please.
    As to Class D (dumb) they sound normally crap having designed a few in the past, best system I have used and heard was the Tripath Hi-Brid Class T but even this had bass pumping and filter problems.
    I designed one which runs at 2MHz and has my special Patent design in the PSU which stops Bass Pumping. But it was only low power at 10KW into 1ohm used on a big vibration table.
    The odd one I made was with a NE555V and MOSFET outputs clocking along at 100KHz in a loud hailer for the MP's (army).
    The output filter designs are nearly always based on standard "T" with no or little thought in the wire used and the type of magnetic material, it seems most are designed around mains filter frequency design, bloody slow.
    leroyd likes this.
  4. CJ14

    CJ14 Retired

    Oh dear You mean that I wasted 5 years of my life in R&D at TQ (well I did as it was nicked from me) and in the 1980,s another 4 years. And now with EWA another 4 yrs, thanks mate love you too he he.
    Not including the 3 yrs at Catch 22, the company that started TQ (mine)
  5. Shadders

    Shadders pfm Member

    I would not worry about it, as long as you got paid. :)

  6. CJ14

    CJ14 Retired

    No the designs and the company and my home a ex-wife were all stolen from me by stealth and snake like manipulation.
  7. Shadders

    Shadders pfm Member

    I am sorry to hear that, i did not mean to be disrespectful or offensive.

    CJ14 and martin clark like this.
  8. sq225917

    sq225917 Bit of this, bit of that

    Bloody hell, that the first full apology I've ever seen on an audio forum
  9. CJ14

    CJ14 Retired

    And it was nice, but without knowing the history of past advent who would guess that the press ignore the facts to.
  10. hifinutt

    hifinutt hifinutt

    Got a bel canto ref 500s this week , my my its sweet !! got loads of prat and transparency but still manages to sound smooth and toe tapping . definately a thumbs up for this icepower amp . [ using a bel canto pre 3 vbs and black ice dac]

    [​IMG]P1060998 by , on Flickr

    [​IMG]P1060997 by , on Flickr
    nicely built with decent binding posts and solid construction . one reason i like BC stuff is its made to last , some of the bc stuff i owned years ago is still around now
  11. Paulq2

    Paulq2 pfm Member

    I have just finished reading all 15 pages....I'm non the wiser but that's down to me and my lack of understanding of the differences between classes of amps, not the quality of discussion.

    I have quite a binary question having just got myself a lovely set of Dynaudio Special Fortys, which I am running off an Exposure 3010S2. That amp sounds 'ok' but I'm considering whether or not to buy something more powerful and was considering one of the Nord amps which I believe are class D. Would I be likely to experience an improvement or degradation in sound quality if I changed and what, if any, advantages would that give me?

  12. mattgbell

    mattgbell Help the elderly and unwell!

    The most obvious difference will be power. As an example, the Nord One NC500DM is 400WPC at 8 ohms, compared to the 110WPC from your Exposure. The Nord is a bit cheaper. Whether that extra power will actually make a difference to your system is another matter.
  13. hifinutt

    hifinutt hifinutt

    The only way to find out is to try one !! I am certain these little Ghent audio monoblocks would impress with the special 40
  14. sq225917

    sq225917 Bit of this, bit of that

  15. Paulq2

    Paulq2 pfm Member

    Thank you. Despite there being a lot in there that I don't fully understand it appears to suggest that it's decent. I guess the question for me is whether it's better' than what I have already - I need to figure that out before I change just for the sake of it (which I won't).
  16. Paulq2

    Paulq2 pfm Member

    I'd love to but am pretty sure Nord don't facilitate home demos. I understand why.
  17. hifinutt

    hifinutt hifinutt

    yes , thats the hard part . occasionally second hand ones come up. there may be folks nearby to come and try with your speakers . whereabouts in uk are you?. next on my list to try is the highly rated PSaudio m700 mono`s .these are about 2550 for two

    I have yet to try a hypex unit , only ever had icepower units and considering these Ghent audio ones can be made at fairly low cost by anyone competent in diy electronics
  18. hifinutt

    hifinutt hifinutt

    from the m700 review [ of which there are a lot !!! ]

    Although PS Audio's Stellar M700 monoblock power amplifier ($2998/pair) is a brand-new design from a team led by engineer Darren Myers, it draws on the company's extensive experience with class-D amplification. Sam Tellig and Kalman Rubinson reviewed PSA's HCA-2 power amp in, respectively, the October and December 2002 issues, and I reviewed their GCC-100 integrated amp in January 2006. The Stellar M700's input stage is the latest version of PS Audio's Gain Cell, which they describe as a "proprietary, fully differential, zero feedback, discrete, class-A MOSFET circuit.

    In the Stellar M700, the Gain Cell drives a 700ASC class-D power module from the Danish company ICEpower. I asked Paul McGowan, CEO of PS Audio, why they chose this module rather than, say, one from Hypex, another class-D specialist. He said that they spent a lot of time listening to modules from various manufacturers, and the 700ASC was the one whose sound quality most closely matched that of the Gain Cell.
  19. Fretbuzz

    Fretbuzz pfm Member

    By more powerful, do you want a more 'powerful' sound to come from the speakers (at normal listening), or more headroom needed (big space to fill at volume or whatever)?

    I think the latter is where class D can really come in.

    If the former, just some experience: I replaced a Nord NC 252 (basic NCore sans input buffers) with a Quad power amp. Both had tonnes of headroom for my set-up, but the Quad brought considerably more weight and body to the sound in normal listening. ie less oomph on paper but more powerful-sounding.

    Both smooth and extended, just a sense of more matter-of-fact starkness with the Nord.

    Could see the appeal of both depending on set up and tastes.
    hifinutt likes this.
  20. clivem2

    clivem2 pfm Member

    The headroom aspect of Class D...the argument seems to hold some logic that Class D "stop" at the at their max power whereas A/B etc can manage peaks better. ie Class D amp won't be able to manage very short duration peaks vs a A/B, is this correct tech gurus? I can't say I notice this issue but I don't drive my Class D amps hard, so I wouldn't...

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