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Class D Audio amps?

MikeJennensMikeJennens
edited August 2016 in DIY
I'm thinking of building an amp with a bit of punch. I'd like a bit more power in the tank than I currently have (70-80 Watts/channel RMS solid state and roughly 60 watts/channel RMS tube). The Class D Audio kits classdaudio.com/all-amplifier-kits/ have intrigued me for a while. Anyone have experience with them?
I'm thinking of going with this one http://www.classdaudio.com/cda-amplifier-kits/cda-250l-power-amplifier-kit/, but I don't know enough about them to make a good decision. Anyone care to break down the differences in them, other than price and output power?
Thanks,
Mike

Comments

  • hongrnhongrn
    Mike, these look like IRS2092 modules, which are very quiet and reliable. You can get by with either the PE stuff, or the eBay stuff (search IRS2092) for a lot less. You can easily buy Antek toroids straight from www.antekinc.com, and build your own power supply. and save a bunch in the process. The results will be the same.

    Hong
  • ani_101ani_101
    The difference between the CD and the SD is that the SD has gain control for each channel. Have heard positive about these amps and was considering getting one... But still haven't.

    Which tube amp do you have. 60w is a good amt of juice for tube.

    @hong, i should start building some amps...
  • MikeJennensMikeJennens
    hongrn wrote: »
    Mike, these look like IRS2092 modules, which are very quiet and reliable. You can get by with either the PE stuff, or the eBay stuff (search IRS2092) for a lot less. You can easily buy Antek toroids straight from www.antekinc.com, and build your own power supply. and save a bunch in the process. The results will be the same.

    Hong

    Thanks for the info Hong!
    ani_101 wrote: »
    The difference between the CD and the SD is that the SD has gain control for each channel. Have heard positive about these amps and was considering getting one... But still haven't.

    Which tube amp do you have. 60w is a good amt of juice for tube.

    @hong, i should start building some amps...

    Hi Ani,
    I have a Jolida SJ-502A. I was fortunate to get it the way I did. A gentleman put it on a local on-line classified site. I was the first one to call and show up at his house with the money. The great part is that he really didn't care about how much he could get for it, he just didn't use it anymore and wanted to get rid of it, I paid a whopping $25 for it. I mentioned to him that the price was extremely low, but like I said, he just wanted to get rid of it.I think it was my score of a lifetime!
    Mike
  • PWRRYDPWRRYD
    I use the ClassDaudio SDS series and they are quite good. There is a significant difference between the (IRS2092) ClassDaudio amp boards and the (IRS2092) Sure amp boards PE sells. Supporting components and PCB layout make a big difference sonically.
  • MikeJennensMikeJennens
    PWRRYD wrote: »
    I use the ClassDaudio SDS series and they are quite good. There is a significant difference between the (IRS2092) ClassDaudio amp boards and the (IRS2092) Sure amp boards PE sells. Supporting components and PCB layout make a big difference sonically.

    Thanks Craig. Any model you might recommend over another?
    Mike
  • PWRRYDPWRRYD
    Great bang for the buck I'd say a CDA-250 board, and an Antek toroid transformer direct from Antek, and a bridge rectifier and some caps from Apex Jr.
  • MikeJennensMikeJennens
    PWRRYD wrote: »
    Great bang for the buck I'd say a CDA-250 board, and an Antek toroid transformer direct from Antek, and a bridge rectifier and some caps from Apex Jr.

    You wouldn't recommend their transformer and power supply?
  • hongrnhongrn
    I'm not Craig, but I wouldn't recommend buying a transformer that can be purchased directly from the manufacturer without a markup. In terms of the power supply, there are so many schematics out there on how to put together a decent power supply for almost nothing. Just scroll down this page to pick your cap size:

    http://apexjr.com/capacitorsR.html
  • MikeJennensMikeJennens
    Thanks Hong. What size transformer and caps would I need? I have an idea of how to build a PS, but will need some help to make one that's better than what ClassDAudio sells with the amp. The power supply and transformer only add either $55 or $80 for both. I don't mind spending a little more if it will yield better results.
  • hongrnhongrn
    Mike, please tell me the amp board you want to get, and I'll walk you through the process of picking a transformer. As an example, look at the PE IRS2092 250W X 2 Class D amp board, and scroll down to the power requirement. This board wants +/-60 to 80VDC, 8A. This means you need to pick the Antek transformer rated at 48VAC (48VAC X 1.4 will give you 67VDC, which is within the required voltage of the amp board). For simplicity's sake. you need at least 500 watts for this board, so the 800VA 48VAC toroid will provide your amp with plenty of juice. This is just an abbreviated explanation, so I hope others will jump in to assist Mike. Thanks.
  • MikeJennensMikeJennens
    hongrn wrote: »
    Mike, please tell me the amp board you want to get, and I'll walk you through the process of picking a transformer. As an example, look at the PE IRS2092 250W X 2 Class D amp board, and scroll down to the power requirement. This board wants +/-60 to 80VDC, 8A. This means you need to pick the Antek transformer rated at 48VAC (48VAC X 1.4 will give you 67VDC, which is within the required voltage of the amp board). For simplicity's sake. you need at least 500 watts for this board, so the 800VA 48VAC toroid will provide your amp with plenty of juice. This is just an abbreviated explanation, so I hope others will jump in to assist Mike. Thanks.

    Thanks Hong. I'll more than likely go with ClassDAudio CDA 250. The aspect of transformers that I don't quite get is figuring amperage and wattage from volt/amps. I understand Ohm's law, but not how to figure anything with VA.
  • JasonPJasonP
    The class D audio amps always looked really solid to me. Moderate cost, excellent performance, etc. I just wish I could see tests on impedance vs. frequency response. I know the IRS2092 is supposed to be pretty good in respect to the variance often attributed to FR variations based on impedance load, but data would be nice to show that. After all, it is dependent on the output filter unless I am mistaken.
    = Howard Stark: "This is the key to the future. I'm limited by the technology of my time, but one day you'll figure this out."
  • PWRRYDPWRRYD
    It is a functuon of the output filter.
  • D1PP1ND1PP1N
    I'll be lurking in this thread. Thx for posting and the responses. 
  • ani_101ani_101
    Is there some easy article or primer that I can read. I am in the dark ages concerning power supplies and amps...
  • hongrnhongrn
    I don't there is, but I started here. Lots of info that you have to put together:

    http://www.decdun.me.uk/gainclone_psu.html

  • jr@macjr@mac
    Check your PM, Hong. 
    I have a signature.
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