Class D Audio CDA-258

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Hello,

I have been a lurker on this group for a few years now but after purchasing a Class D Audio CDA-258 amp board I felt the need to share. I have a Yamaha M-40 amp that was hit by lightening. The main board was a mess but the huge power transformer was still in good shape so I decided to drop the CDA-258 in the chassis and use the existing power supply. It has worked out fantastically and I couldn't be more pleased! :D

I am using a vintage McIntosh C26 preamp to drive it right now while I build a new Pre to go with it and man does it sound great. The bass is tight and low, the highs are detailed without being fatiguing and the midrange is literally tube like. I have been running a McIntosh MC2100 that I rebuilt about 6 months ago and while it sounded really good this amp retains the MC2100’s best qualities but extends them even further.

I will get some pictures up later if anyone is interested in seeing it. I have enough room to add at least one more CDA-258 and may do that and run them bridged for 500 watts into 8 ohms. At 250 watts now though, it is more power than I have ever had and sounds amazing. Even if you don’t play it loud, having more power just seems to make the music…well, more powerful sounding.

I also want to thank Tom at Class D Audio. He answered my questions promptly and was fantastic to work with. I placed an order with him and had it on the East Coast in about 2 days. Amazing service.

Definitely check them out if you have the chance. :up:

Rob
 
Sorry

Didn't mean to jump on you. I am very excited about my amp and was just disappointed to feel as if I was being accused of spam. I actually work in educational technology on the East Coast.

I apologize if my post came across as an ad. Maybe I should work in marketing!;). I am just excited about this project.

I would still like to talk about it if anyone is interested.
 
Thanks! I appreciate your response. I actually have an undergrad in Electrical Engineering and have been designing and building my own solid state and tube audio electronics for over 20 years as a hobby but when it comes to Class D amps with their rf issues etc I have no interest in starting from scratch! ;)

Besides, for the price, you can't beat these new boards that are coming out from Sure, Class D Audio and many others.

Thanks again.
 
There is a huge thread on these over on Audiocircle in the "Cheap and Cheerful hifi" section. Its title is something like "great amp for under $120" it is a stickie at the top of the page.

I thought about these units long and hard. Having read through the AudioCircle thread, I got fed up with all the modding needed to cure various quirks. I get a bit bored with the endless threads that start of with "This is the best thing since sliced bread", and end up with " I replaced X, Y, and Z because it stops it sounding like ****". I know that this is a diy forum, but either something is good, or it is not.

I ended up buying Hypex UCD180HG hxr in order to avoid any doubt. I have not implemented them yet...

The Class D Audio amps are an excellent price, though not as good as hifimediy. I have just bought one of these to comapre with the Hypex. Should be interetsing.
 
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I'll have to check out that thread. Thanks for the heads up. I agree, I don't like having to do all of the mods either if I can avoid it. I honestly see no need so far with this board. I tried the Sure boards and did not like the sound at all. They definately need some mods but I enjoyed playing with it none the less and still think you can't beat the price tag of the Sure boards even if the sound isn't my thing.

I will be curious to hear your comparison of the Hypex and hifimediy board. That is a Tripath based amp, right? I have found the Tripath amps to be hit or miss sound wise. I had a low powered one that sounded pretty good but like I said, the Sure board I have doesn't really do it for me but there are a ton of suggested mods for it that I haven't tried yet! :p
 
I thought about these units long and hard. Having read through the AudioCircle thread, I got fed up with all the modding needed to cure various quirks . . . I know that this is a diy forum, but either something is good, or it is not.
Almost all the “issues” with the original (and still available) classDaudio “CDA” series boards came from their origin . . . they were almost direct copies of the IR “evaluation” board that was intended to provide designers with an introduction to the IRS2092 modulator and they are intended to be used with appropriately matched equipment (suitable source and load impedances). As with *any* electronic equipment I’ve ever encountered their components are chosen at least in part based on cost and size (to facilitate easy board layout). There was a presumption of some level of knowledge (about electronics, and design) that was not present in all the “early adopters” of the “diy” amps (many of whom saw “RCA” input connectors and just assumed they could drive the boards with *anything* that had “RCA” output connectors, and who had little understanding of issues of gain and level matching). A good part of the AudioCircle “cheap and cheerful” thread simply addresses the difficulties experienced by those less-than-clueful “early adopters”. But once past those issues (or in the hands of someone with electronics experience) the “CDA” boards are excellent amps, inexpensive and free from audible distortion (most notably free from the crossover distortion that is the bane of most “linear” solid state amps). But you do have to know what you’re doing to properly apply them.

The “SDS” series of amps introduced an input buffer to make the (otherwise identical) boards more nearly “plug-and-play” for the inexperienced buyer (higher input impedance, non-inverting, easy gain adjustment) . . . but still leaving room, perhaps, for improvement in (some) component selections (we are DIYers, after all), and a need to pay some attention to load impedance. In most applications they will work just fine “out of the box”.

I have just bought one of these to comapre with the Hypex. Should be interetsing.
If you hear *any* difference it will be because you did something wrong in the implementation(s) . . . used properly both are excellent (essentially flawless) amps.
 
I am sorry if I appeared to be slagging the CDA modules. I did not mean to. I was just venting about over enthusiasm, which then turns into an endless process of modding, and people admitting that the units were not that great afterall. It appears that this is not the case here.

I was going to use one of the CDA modules with a Nelson Pass B1 buffer to handle volume control and impedance matching. Seemed like a nice solution.

If you hear *any* difference it will be because you did something wrong in the implementation(s) . . . used properly both are excellent (essentially flawless) amps.

$45 Hifimediy vs $500 Hypex - No difference? Blimey

If the CDA are excellent value, then perhaps the Hifimediy amps are extraordinary value. We will see. As an earlier poster has pointed out, the Tripath sound is not for everyone. I like my little TA2020 Diyparadise Charlize amp though.
 
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