I received one of these black tpa3255 boards today and am listening to it right now. Paid $64 with shipping. Here are some observations mostly about the tpa3255:
Using mean well se-600-48 power supply (smps,600W,48V,12.5A) running right at 48V.
The amp board is directly connected to the preamp with no separate volume pot.
* The background is dead silent, running wide open.
* Bass is excellent, even at low volume!
* Great low-level detail, high-res
* 4 watts more efficent at the wall plug compared to tas5630b...which is noticeable in that it gives off far less waste heat. The ouput inductors on my 5630 board stay hot all the time while those on this tpa3255 board are cool to the touch.
This amp is waaaay overkill for my 91dB efficient speakers, but it sounds great.
Regarding use of lower-voltage power supplies: I'm not trying lower voltages with this board because of my experience with the tas5630b. I was trying to use the 5630 with 32vdc and it was very frustratingly susceptible to EMI noise. Going to 48V almost completely eliminated the EMI noise. Dunno why it made that particular difference.
BTW I also have one of the 3eaudio tpa3255 boards, but i have not yet tried it out. I am planning a more "special" build for that board.
Awaiting your comparison of these 2 boards.
I am planning to purchase a 3255 board but only ONE.
I just ordered a 3251 EVM. Just a hair under $82 (USD) with shipping. Hard to pass up at that price.
Not as cheap as the cheapest 32xx boards of course, but I figure TI won't stuff the board with counterfeit or under-spec'ed parts. Also, based on what others said, the EVM boards are supposed to be pretty high-quality PCBs, and easy to work with if I want to do mods. And if I'm not mistaken, the EVM board was used to create the datasheet measurements/graphs (albeit with a much fancier power supply than I have). So PSU quality not-withstanding, I'm guaranteed to get datasheet performance. (I'm assuming it takes real engineering to match or best the datasheet performance; likewise it's too easy to get worse performance.) I also like that the EVM has a jumper for selecting single-ended or differential input (the 3e-audio board has this feature too).
Not as cheap as the cheapest 32xx boards of course, but I figure TI won't stuff the board with counterfeit or under-spec'ed parts. Also, based on what others said, the EVM boards are supposed to be pretty high-quality PCBs, and easy to work with if I want to do mods. And if I'm not mistaken, the EVM board was used to create the datasheet measurements/graphs (albeit with a much fancier power supply than I have). So PSU quality not-withstanding, I'm guaranteed to get datasheet performance. (I'm assuming it takes real engineering to match or best the datasheet performance; likewise it's too easy to get worse performance.) I also like that the EVM has a jumper for selecting single-ended or differential input (the 3e-audio board has this feature too).
Hello! And welcome! First post and everything
If you do not mind me asking, what amplifiers have you tried with those speakers previously?
Just want to know the basis of your opinion. I am most curious about a possible comparison between the cheap stuff and the 3eaudio one, but if you've had some good class AB or class A amps it is nice to know that too.
I really want to LIKE class D, but I find that most of the class D lacks something a good class AB or A has. Ever since trying some of the first Zap pulse modules years back (which where quite good imo) I always felt there was something "lacking", be it either noise, detail, low end "oomph", poor high freq response. Really thought the TPA3116 and 3118 would be good, but there's the good 'ol anticlimax waiting for me again. The thing is probably that the distortion comes on so quickly, that even when playing low you still get it.
... Hoping that the TPA3255 will be good at least up to 20 watts, should handle some transients then with power up to 80w before it's unbearable.
Hi
should you able to check the 'POP' noise ?
http://www.diyaudio.com/forums/class-d/287470-tpa3255-diy-discussion-design-etc-24.html#post5174007
Last edited:
That is the EXACT same experience I had with the Zap, really good stuff at low levels and if you do not do critical listening it can be quite good at a party etc. But oh-so boring when you sit down to enjoy the music.
Just bit the bullet on one 3251 and one 3255 EVM boards from TI. 174$ for both :-D
Have to figure out if I have some power supplies and whatnot laying about.
Last edited:
Generally agreed. But one mod that might make sense is adding post-filter feedback. IIRC, the EVM was designed with solder pads or through-holes to facilitate this.
Hello! And welcome! First post and everything
<snip>
Hi Kaffiman, thanks for the welcome.
The speakers I use are crossoverless fostex 8" full-rangers that are well-broken-in at about 9 years old
. I have used these speakers with many, many amplifiers in that time. But it has been a long time since I used them with a solid state amp! In fact you might say those speakers are the reason I am using class D today. Because when I first got them, I used them with solid state amps but the sound had a kind of mushy quality and couldn't resolve low-level detail. Fine for low-efficiency speakers, but high efficiency is very revealing. So I tried a Tripath T2020, it has been nothing but digital for me ever since. Digital amps haves can have "the magic" but not all are created equal. I have followed class D for a long time and I can tell you that RIGHT NOW the technology is hitting a peak because of the amount of power they can produce and the efficiency with which they do it. The latest batch of TI TPA amps is really amazing.Amps I've used previously:
* The T2020 of course
* LM4766 because I ultimately found the T2020 underpowered for dynamic material
* NuForce DDA-100
* NuPrime IDA-8 (has class A preamp section)
* TAS5614LA
* TAS5630B
* IRS2092
* And most recently the TPA3255
When comparing to solid state, it's important to remember that class D amps are typically rated for a 4-ohm load @ 10% distortion. (you have to read the fine print) and can produce more power than rated at higher levels of distortion. Even the TPA3255, which has awesome specs, hits a wall of distortion below its rated power.
What I am getting from the 3255 is a solid black background and excellent detail. It should do great with high bit/sample rate material.
As somebody else said, the class D amps are cheap enough that you can try to pick a good one, give it a shot, and if you don't like it you haven't blown a ton of money (as opposed to some of my more regrettable audio purchases). And be sure to use a power supply that is strong enough or it is guaranteed not to sound good. You can't buy a complete amp including power supply at the moment, but those will come.
Not sure whether to put this here or there...but yes, there is a VERY nasty and *dangerous* pop if you either turn on or off power to the board while it has an input signal. I have been turning off my preamp first. Ideally I would have a separate power switch for the amp board, but haven't done it yet and just have it connected directly to the power supply.
Also I can confirm that both the FAULT and CLIP LEDs are illuminated. That was troubling at first and then I just assumed that somebody in the design/build process made a mistake because it plays fine. It would be much more preferably to have properly working LED indicators.