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Why so few higher powered Class D stereo amp boards?

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  • Why so few higher powered Class D stereo amp boards?

    There are several, actually many 50 watt or so amp boards that PE and other suppliers sell, but I see very few higher output boards available.

    For instance, The Dayton
    DTAPRO
    has around 100 watts for the LR speakers and there's a Lepai that does as well, the
    LP1601S, and these are finished amps in cases, but there's
    not much in the small amp board category.

    I like this amp board,
    The TDA7492, I
    have used it a few times: https://www.parts-express.com/tda749...2x50w--320-606

    It does 50 watts stereo and is nice and small, but I'd love a bit more power, say 75-85 watts in a similar size would be great.
    I think the higher output boards like the Dayton DTAPRO and the Lepai LP1601S use BTL to get to the 80-100 watt per channel mark, but is it that hard to do so in a compact form factor?

    Just wondering if there is a reason why 50 watts seems to be the limit on the small boards; and does anyone know of an amp board similar in size to the TDA7492 that puts out a bit more watts, like 70-80 or so into 4 ohms? Even up to 20 or 22 volts would be okay.

    Thanks for any thoughts,
    TomZ
    *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

    *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

  • #2
    My guess is the need for more serious heatsinking, and beefier supplies and parts in general would price them out of the market they're in. Obviously there are players like Hypex in the higher power market.
    Francis

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    • #3
      N core and pascal both have great products, just not cheap.
      craigk

      " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

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      • #4
        I would agree that power supplies factor in. DC laptop power supplies are easily repurposed. I too would like to see more higher power offerings like the TPA3255 from more local sources. I'm working on a dual monoblock Icepower 125asx2 at the moment.
        My Builds - Overnight Sensations w/ Voxel - Speedsters in surplus boxes - Zaph B3N's in bamboo - Classix II in BR-1 cabinets - Dual TPA3116 D2 amp in an old music box - Mariposas

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        • #5
          +1 on the power supplies. That 50W mark is the 24V supplied BTL range, above that you need some more serious volts and amps working for you. The Sure amp boards are the only options at PE, and there are quite a few of those up in the 100's of watts range.
          Electronics engineer, woofer enthusiast, and musician.
          Wogg Music
          Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus

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          • #6
            I’d like to see more digital amps that are rated, even at 50 watts, but with less than 1% distortion. Many of these digital amps are rated at at 10% for their advertised power output.

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            • #7
              Class D Audio makes some great sounding, high powered class d amp boards.

              http://classdaudio.com/

              Their lowest power board (CDA-120) is 60 watts RMS X 2 into 8 ohms, 120 watts into 4 ohms. Their most powerful (SDS-500) is 250 watts RMS X 2 into 8 ohms.

              Some are bridgeble into mono. For example, the CDA-120 is 240 in mono.


              Originally posted by westrock2000 View Post
              I’d like to see more digital amps that are rated, even at 50 watts, but with less than 1% distortion. Many of these digital amps are rated at at 10% for their advertised power output.
              Not to be picky, but class D amps are not digital amps.

              All the amp boards by Class D Audio are better than .02%.

              Typical Class D Audio amp board specs look like this:
              Model SDS-250
              Number Of Channels 2
              RMS Power Per Channel 8 Ohms 125W RMS X 2
              RMS Power Per Channel 4 Ohms 250W RMS X 2
              RMS Power in Bridge Mode 500W Into 8 Ohm Only. Single Channel
              Input Sensitivity 2V
              Total Harmonic Distortion (THD) Better than .02% (normal listening is about .003%)
              Frequency Response 10hZ to 35KHz
              Input Impedance RCA 30K
              Input Impedance XLR 45K

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              • #8
                SilverD mentions the TPA3255 (and there is also TPA3251). There is a lot of discussion of these over on Diyaudio. The two more highly regarded implementations are the Texas Instruments evaluation (TI EVM) boards and the boards from 3eaudio (they have a website and sell on eBay). There are a lot of Chinese boards on eBay that actually get pretty good reviews. There is also a current Group Buy being developed there, where someone is trying to develop a reference quality board and currently experimenting with different PCB layouts.

                High powered IRS2092 boards at Connex Electronics.

                If you go to the amplifier boards even on PE, there are quite a few high-powered Sure boards. I know you know the PE site pretty well, so maybe I'm missing some reason these don't fit your needs.

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                • #9
                  Originally posted by westrock2000 View Post
                  I’d like to see more digital amps that are rated, even at 50 watts, but with less than 1% distortion. Many of these digital amps are rated at at 10% for their advertised power output.
                  Usually there is quite a bit of information supplied on the power and distortion. You are right they all report the distortion at 10%, but I just read the spec sheets and consider the board's real power at whatever it can produce at 1% or less distortion. The other tricky part is some are rated a 2 or 3 ohms but don't really outperform the lower powered units at 4 or 8 ohms due to however Class D works.

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                  • #10
                    I have built two DIY amps with the ClassDaudio amp boards. They do sound very clean, powerfull, and natural. I like them both (one is a SDS and the other a CDA).​ But they both require a pretty big power supply. I built both of mine with over sized toriod transformers and separate rectifiers and cap banks for each channel.

                    If you are looking for maximum watts per dollar I would say you are better off just buying a pro amp like the Crowns. Building a DIY amp with a ClassDaudio board, toroid transformer, power supply parts, and a case will cost quite a bit more. But in my opinion will sound better. YMMV
                    Craig

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                    • #11
                      Tom,

                      What are you looking for? Something for 2 channel use?

                      I think the Crown XLS 1502 is good value @$350

                      Some measurements here:
                      https://www.audiosciencereview.com/f...1502-amp.6062/


                      Or are you looking for some boards for DIY use (eg. active speaker system)?

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                      • #12
                        Originally posted by PWR RYD View Post
                        I have built two DIY amps with the ClassDaudio amp boards. They do sound very clean, powerfull, and natural. I like them both (one is a SDS and the other a CDA).​ But they both require a pretty big power supply. I built both of mine with over sized toriod transformers and separate rectifiers and cap banks for each channel.
                        As a disclaimer, I have NOT built or listened to all of these boards but have read a ton on Diyaudio. This is based on reading and can be taken with a grain of salt:
                        • Hypex boards are really really good, probably the best Class D available at this time for DIYers. And really expensive relative to the options below.
                        • ClassD audio are very good. (I believe based on IRS2092 chip but with a very good implementation but not 100% sure of this). Much less expensive than Hypex but quite a bit more than the options below.
                        • Connex Electronics. Good IRS2092 boards with many posts on the internet that people can't tell the difference between these and ClassD Audio's boards. (Connex Electronics makes well regarded SMPS power supplies (which often cost more than the amplifier boards))
                        • There is a member at Diyaudio "LJM" that has designed a lot of boards. They are sold as cheap Chinese boards on eBay by various sellers (LJM does not actually make and sell the boards himself.) There are a lot of reviews of these and similar to the comment above many can't tell the difference between them and the Connex and ClassD Audio, but you have the risk of buying from less reputable sellers, although you can tell who the more reputable ones are. Note, a lot of these come in PCB's and/or kits and one of the additional risks is that there may be counterfeit parts as well as the fact that if you buy the unassembled PCB you have to solder the parts to the board.
                        TPA3255 is supposedly better than the IRS2092 boards if implemented correctly, but most of these are cheap Chinese boards on eBay right now so uncertainty is high (although general reviews are still good). The 3eaudio boards are supposedly a better implementation.

                        Also, the SMPS power supplies (better quality ones at least) supposedly work as good toroidal supplies on class d chips which is not the case for class a and a/b amps.

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                        • #13
                          Thanks for the discussion guys. I have some sites to check out now.
                          my intended use is really for my bantam table radio, which could probably use just a few more watts than the little 50 watt board I've been using. That board is only 20$ though, so jumping up to $120 is too big a jump for what it is. The size is like 3" by 3", so it's also pretty tiny as well, which fits here or there easy enough.
                          Ive seen some half decent boards on Amazon and aliexpress but it's the unknown aspect... Noisy, hum, poor quality etc. that is the rub. I'll check out these suggestions Mañana though.
                          TomZ
                          *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                          *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                          *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

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                          • #14
                            The ClassD kits fit nicely in a 16" sq by 4" high Par Metal chassis. I built two 250 watt models. They are not table radio or boombox appropriate.

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                            • #15
                              Tom, I think I know what you need! (Although I could be wrong )

                              TDA7498 (PE has one and with power supply) there are cheaper ones out there, but your comment about noisy, hum, poor quality applies.

                              The other problem with some of these higher powered boards is that the typical power brick is 12-19v which may not give you the voltage to take advantage of the extra power anyways. Search for Orginal FX Audio 32v Power Supply on Aliexpress (about $13 plus $8 s&h which is what you will pay on ebay for a Dell 19v adapter or something similar).

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