this boards have no problem even outputing ~40w into 4 ohm speaker without heatsink while chip is running on 64-65 degrees, but one board has 10 degrees difference that i cant quite figure out what is issue and i am wondering could it be actual chip active device difference?
difference is amplified without heatsink obviously that is why i test it without so even slight differences are appearent.
difference is amplified without heatsink obviously that is why i test it without so even slight differences are appearent.
same pcbs, same components, same batch. also why remove output filters? that makes no sense.
on a positive side, other stereo btl pcb with tht components and post filter feedback tested and working perfectly.
on a positive side, other stereo btl pcb with tht components and post filter feedback tested and working perfectly.
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if one is hotter than the other either one is using more power or one is dissapating heat different than the other. If one of the caps in the output filter is a little leaky or if one of the inductors is leaking a bit to the core or if the core material is a little different etc.. If you are testing without a heatsink perhaps one of the chips is dissapating heat better to the circuitboard than the other.
My advies would be: don't. There is no audible or measurable improvement to be expected, you can only make matters worse. AK has a reason for putting these chips on the spec sheet afaik.
Thanks.
Anyway, I own a pair of OPA1622...it doesn't eat bread to test
The OPA1622 is one of the reasons I am happy to belong to the human race. It drives a low Ohms headphone with incredible resolution. You could use that ability to use low value resistors in the feedback loop. With the DAC, that might give you a somewhat better noise figure. But you would have to change more than te the opamp, and in all likelihood, noise is set by the circuitry surrounding the DAC, the part supplying the Vref is most critical here. So you might have to change that too to achieve an improvement.
But playing is fun, so keep us posted. Nothing will break.
Thanks, for your information, I only drive some Floor Speakers @ 93DB / 100W RMS, made in France (hi end speakers so).
I use tha AK4493EQ to drive those speakers, I don't use headphones.
If you want to change Op-amps, it might be a good idea to try the ones with higher amplification first. Probably the DAC.
Changing OP-amps has become useful with cheap Chinese audio modules, like DAC´s, buffers, pre-amps, chip-amps etc. These modules are full or part copies of well known designs and can sound really well if applied right.
A real NE5532 costs quite some money even bought in huge numbers, while a cheap industry OP-amp is around 1 Cent. So instead of buying a 48 Cent TI part, the Chinese engraves the no cost part with a TI like logo and feels smart.
If you now change such a, maybe even not audio part (!), for a real OPA 1622 or the like, you will hear a huge improvement.
On the other side, if you then change the real OPA1622 for a real NE5532 you will in most cases not only hear no difference, but even if there is one, you will not be able to tell which one sounds actually better.
I rare cases one OP-amp may be audible better than another, if the surrounding circuit benefits of it´s advanced driving features.
If possible, do a A-B test, the only way to really tell a difference. Otherwise you may fool your self, even while trying to be objective.
Changing OP-amps has become useful with cheap Chinese audio modules, like DAC´s, buffers, pre-amps, chip-amps etc. These modules are full or part copies of well known designs and can sound really well if applied right.
A real NE5532 costs quite some money even bought in huge numbers, while a cheap industry OP-amp is around 1 Cent. So instead of buying a 48 Cent TI part, the Chinese engraves the no cost part with a TI like logo and feels smart.
If you now change such a, maybe even not audio part (!), for a real OPA 1622 or the like, you will hear a huge improvement.
On the other side, if you then change the real OPA1622 for a real NE5532 you will in most cases not only hear no difference, but even if there is one, you will not be able to tell which one sounds actually better.
I rare cases one OP-amp may be audible better than another, if the surrounding circuit benefits of it´s advanced driving features.
If possible, do a A-B test, the only way to really tell a difference. Otherwise you may fool your self, even while trying to be objective.
Thanks for this feedback...
I made a first test and it is really weird... I only buy my amp parts from a certified seller. I mean my OPA1622 are genuine.
I switched the original NES5532 > OPA1622... Sound became noisy and unpleasant. I will do the same test with some OPA627 and I will let you know. This probably means that the NES5532 are genuine )
I just read this post about this 3 channel TPA3251, which is exactly what I need for my 3-way active speakers.. but sadly I can't find them anymore on 3E's Ebay store..
Does anyone know of any comparable 3-channel board?
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Ho amigos,
Just received my new TPA3255 amplifier.
I will upgrade the OPA tonight > OPA1622
Out of the box, it sounds amazing with the original NES5532 . I checked the components from inside and seems this board is serisously well made. We can see Nichicon capacitors, alps potentiometer etc
I will let you know my final opinion once I have updated the OPA
It runs actually with a Linear PSU @ 40VDC
Somes pictures :
Just received my new TPA3255 amplifier.
I will upgrade the OPA tonight > OPA1622
Out of the box, it sounds amazing with the original NES5532 . I checked the components from inside and seems this board is serisously well made. We can see Nichicon capacitors, alps potentiometer etc
I will let you know my final opinion once I have updated the OPA
It runs actually with a Linear PSU @ 40VDC
Somes pictures :
Time test )
I put the OPA1622 inside and testet with my hand mande linear PSU (40VDC)
I also connected my P1 Preamp with some Tung Sol US tubes....
It sounds just fantastic ! Lot of dynamics, sweet and absolutely noiseless.
I need to burn it a bit more... I am really happy for now.
The only issue is the lack of an Anti Pop circuit... IF SOMEONE CAN HELP TO AVOID THIS ?
I put the OPA1622 inside and testet with my hand mande linear PSU (40VDC)
I also connected my P1 Preamp with some Tung Sol US tubes....
It sounds just fantastic ! Lot of dynamics, sweet and absolutely noiseless.
I need to burn it a bit more... I am really happy for now.
The only issue is the lack of an Anti Pop circuit... IF SOMEONE CAN HELP TO AVOID THIS ?
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