TPA3255 - all about DIY, Discussion, Design etc

xkr971 & Vacuphile...
I read your last posts...
And see no reason for you to (apparently) disagree with what the other one is saying, because...
At the end of the day, you are saying the same thing!!!!:)

xkr: a fully driven TPA3255 in BTL mode shall output a signal about 90-95Vpp (sinewave 1kHz etc...): this is correct, as you scope shows it (of course, that's a measurement)...
BUT
your scope doesn't show anything different than what vacuphile says...
The thing to capture here is:
On the positive semi-cycle of the sinewave, one output node is driven by the TPA at +48V (say) close to saturation, while the other output node is at the same time driven to zero volt (ground): these are the 48V from vacuphile explanation...
Then on the negative semi-cycle, the first output node now reaches zero Vold (ground) while the second output node goes to +48v....
As it can easily be understood (I hope):
1/-The scope shows 96Vpp because it shows the differential voltage between the two output nodes, it is NOT showing a voltage w.r.t. ground...
2/-Maximum voltage from any output node w.r.t. ground never exceeds +48V (and I didn't say +/-48 but actually +48V) as vacuphile points at.

So both of you are right..:):):)
 
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Hi Kalamin,
I might be wrong, but I think Vacuphile has always been saying that you can’t get 96Vpp. I never claimed to try to measure them relative to GND. I have read his earlier posts on my thread and he was saying how it violates physics and that you can’t get more voltage than your supply. Maybe at DC levels you can’t, but this is AC and floating. What I am talking about is how much voltage can the amp put on the load. We all know with BTL amps, you cannot ground one of the outputs. What I am saying is that the blue board TPA3255 from eBay/AliExpress cannot even make more than 48vpp in differential BTL output mode - not referenced to GND. That’s a problem.
 
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thank you both. I decided to buy a switching mode mean well 500 watt 36V power supply. I might end up using this on my open baffle speakers and i wanty to make sure that it can drive two 8 ohm woofers that are wired in parallel or in fact any other commercial subwoofer so its better to be safe with 4 ohm operation.

I dont know if this decision was smart as far as reliability of operation is concerned, but from previous experience I judged the fan on these mean well Switch modes to be loud so had to make sure to get a fan free model, thats why i had to rule out many 600 watt models and other 500 watt models that had fans and get a model without fans. hopefully it was the right decision. i know i cant have my amplifier in my living room with loud fan, just out of the question. I did see some models that i think you can turn ther fan on or off but I just decided to go with one that is fanless. any thoughts on that? i got this model:

An externally hosted image should be here but it was not working when we last tested it.



Now i need to figure out how to configure the amp to run in balanced mode with XLR inputs. I read the manual and it does say that the default mode is BTL but it doesn't show the exact wiring required to circumvent the RCA inputs and use XLR connectors.
 
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