How about PFFB mode? Looks like it is recomended by TI...
http://www.ti.com.cn/cn/lit/an/slaa702/slaa702.pdf
Anybody done this?
Maybe I'm wrong, but somewhere I got the impression that PFFB also decouples the output filter from speaker impedance. I.e., you (almost) always need an output filter with class D amps to filter out the high-frequency switching noise. The drivers themselves are effectively part of this filter, so if you change from 4ohm speakers to 8ohm speakers, your filter has changed. Maybe you can hear it, maybe you can't; but technically speaking, if it was previously optimal with 4ohm speakers, it's no longer optimal with 8ohm speakers. I thought PFFB addressed this problem, so the amp itself is no longer tied to a certain speaker load for optimal filter performance.
Maybe I'm wrong here?
It's going to broaden the impedance space that the inductor will work well, but it's still best to match it to your load.
IMO, lowering the input sensitivity and noise (depending on input opamp and feedback network) is as valuable as correcting for the inductor. I invariably find myself wanting less gain rather than needing to aggressively attenuate my input signal. But that's me.
IMO, lowering the input sensitivity and noise (depending on input opamp and feedback network) is as valuable as correcting for the inductor. I invariably find myself wanting less gain rather than needing to aggressively attenuate my input signal. But that's me.
Generallyl you are right. PFFB reduces effective output inductance thus making the output less sensitive to load impedance variations.
is this also the case for the TI evaluation boards? my current design calls for the amp and minidsp to be powered from the same smps, so switched on and off together.. i also wish it to be foolproof when others use it.
i will also be using it with some quite delicate speakers ( not going anywhere near the full rating of the amp...)
if i get a full amplitude "pop" i will be digging my cones out of the opposite wall.
I've had a 3152 board sitting in the box for awhile now, but have not decided on the power supply. I know there are a number of options, the meanwell type PSU, also thinking about the ICE2QSO3G board sold by 3eaudio thats only 5.5a which concerns me, and another one here: 36V 9A 12V 2A 350W Dual output switching power supply Input 110V/220V | eBay
It seems this group has good luck with the 3eaudio, but at 5.5a am I missing out? I will start a thread on my build, will be the 3152 combined with an older bottlhead foreplay housed in an old silverware box.
But to get the last piece any advise would be really appreciated.
Thanks
It seems this group has good luck with the 3eaudio, but at 5.5a am I missing out? I will start a thread on my build, will be the 3152 combined with an older bottlhead foreplay housed in an old silverware box.
But to get the last piece any advise would be really appreciated.Thanks
Your MiniDSP should take care of that as you can mute/shutdown the amps with GPIO functionality.
I've had a 3152 board sitting in the box for awhile now, but have not decided on the power supply. I know there are a number of options, the meanwell type PSU, also thinking about the ICE2QSO3G board sold by 3eaudio thats only 5.5a which concerns me, and another one here: 36V 9A 12V 2A 350W Dual output switching power supply Input 110V/220V | eBay
It seems this group has good luck with the 3eaudio, but at 5.5a am I missing out? I will start a thread on my build, will be the 3152 combined with an older bottlhead foreplay housed in an old silverware box.
Do you mean 3251?
At any rate, I ordered a Connex SMPS300RS (36V output) for my TPA3251D2EVM. For the single-rail version, Connect claims 8amps nominal at 36V (and 10.5amps peak). $65 base plus $20 shipping to USA. At $85 it's a bit cheaper than the 3e-audio PSU, and capable of higher current.
I've used Connect SMPSes for other projects and always been happy.
please don't believe any thing before you listen or measure it,specially things from some new or not professional supplier.
i am not saying that which board is best/bad for you,but someone did only copy and translated the spec from Ti and make just make them what it should be,and you never know unless you try it.
i am not saying that which board is best/bad for you,but someone did only copy and translated the spec from Ti and make just make them what it should be,and you never know unless you try it.
Hi,
Isn't there is a reset control TPS3802K33DCKR on the 3255evm to monitor the PVDD if drops below a preset reference then trigger a reset? I don't quite understands why it still pops at power on and off?
I have to put the S1 on reset position before power on and set to Normal when D5 and D6 are on in order to run without pops. I had to do the same before power off the 3255.
What will be a better way without this manual switching on S1? You can't turn on the pre-amp after the power amp, that will create another pop.
Thanks
that is a little bi sad,same in the YJ board which i complained few days
http://www.diyaudio.com/forums/class-d/287470-tpa3255-diy-discussion-design-etc-24.html#post5174007
http://www.diyaudio.com/forums/class-d/287470-tpa3255-diy-discussion-design-etc-24.html#post5174007
I understand the meanwell PSU fans turn on when they get hot, but "most of the time" aren't spinning.
I'm also looking for an SMPS for my just purchased TPA3255 EVM - as I intend to drive 98dB sensitive LF drivers within an active system the quietest (in terms of audio signal noise) SMPS would be best for me, is anyone else driving high sensitivity drivers and can report silence from the listening position?
Is the ripple measurements that some SMPS have a factor for the background noise?
I posted a possible fix here:
TPA3255 - all about DIY, Discussion, Design etc.
The EVM reset circuits behaviour is also bound to the feedback voltage of the used buck regulator. If it still pops, the time constant isn't big/long enough. -> That's why you need to use the external SHDN/RESET Switch.