Sorry, but I'm confused. Each of the four amplifiers have a 21.5 db gain, or 11.88 times. With the maximum PS voltage of 53.5, the maximum output voltage is 18.9 volts RMS. 18.9 / 11.88 = 1.59 volts input sensitivity per amplifier.
Mike
http://www.ti.com/lit/ds/symlink/tpa3255.pdf
Scroll down to Electrical Characteristics. You will also notice that even though the chip can accept 7 volt input P-P, but that will clip the output.
Mike
Scroll down to Electrical Characteristics. You will also notice that even though the chip can accept 7 volt input P-P, but that will clip the output.
Mike
TPA3255 doesn't work!
Hi,
today I finished my TPA3255EVM arrangement. At least I thought that I did. I did the modifications on the reset circuit that were suggested by chermann here, jumpered the board for 2.0 BTL mode, and connected INA and INB to one input transformer, and INC and IND to the other one. Then I connected it to a Meanwell PSU that I had adjusted for 53.5 V output, two 4 ohms dummy load and powered it. Within half a second the FAULT LED turned on
! Setting the switch to reset turned the LED off again, but within half a second after setting it to normal the LED lit again.
I measured an offset of about 0.5 V at outputs A and B. The scope showed a very unstable sinusoidal signal of 50 kHz at outputs C and D.
Unfortunately the user's manual doesnt give any debugging advice, so I'm lost with the issue.
Where do I need to start to solve the issue and to make the board work correctly?
Best regards!
Hi,
today I finished my TPA3255EVM arrangement. At least I thought that I did. I did the modifications on the reset circuit that were suggested by chermann here, jumpered the board for 2.0 BTL mode, and connected INA and INB to one input transformer, and INC and IND to the other one. Then I connected it to a Meanwell PSU that I had adjusted for 53.5 V output, two 4 ohms dummy load and powered it. Within half a second the FAULT LED turned on
! Setting the switch to reset turned the LED off again, but within half a second after setting it to normal the LED lit again.I measured an offset of about 0.5 V at outputs A and B. The scope showed a very unstable sinusoidal signal of 50 kHz at outputs C and D.
Unfortunately the user's manual doesnt give any debugging advice, so I'm lost with the issue.
Where do I need to start to solve the issue and to make the board work correctly?
Best regards!
Wow! Without these input transformers there's one or two short glitches on the FAULT LED, then it stays off.
Why does the board behave this way? And what can I do if I need symmetrical inputs via XLR terminals, with the board being jumpered for symmetrical mode, and unbalanced, but floating (due to avoid ground loops) RCA inputs as well?
Best regards!
Why does the board behave this way? And what can I do if I need symmetrical inputs via XLR terminals, with the board being jumpered for symmetrical mode, and unbalanced, but floating (due to avoid ground loops) RCA inputs as well?
Best regards!
No, the input transformers aren't CT. That's why I asked this question.
In the meantime it turned out fine, after I've rotated the board by 180 degrees
.The only issue that is left is the lack of input sensitivity. I'll try to source four of these super tiny (like a grain of sand!) resistors of 22 kohms.
Best regards!
I'm planing on building a 5 channel poweramp with the TPA3255 boards. Ideally the 3e one's.
Preamp will be an AVR witch cinch out's. Speakers will be 5x the Klipsch RP-280F on fullrange without Subwoofer. So I'm using a 5.0 system.
My speakers are from 3.31 Ohm up to 16.07 Ohm. They are specificated as 8 Ohm speakers.
So my question is: Which 3e board to use?
The TPA3255 stereo-board or the mono-channel one?
Preamp will be an AVR witch cinch out's. Speakers will be 5x the Klipsch RP-280F on fullrange without Subwoofer. So I'm using a 5.0 system.
My speakers are from 3.31 Ohm up to 16.07 Ohm. They are specificated as 8 Ohm speakers.
So my question is: Which 3e board to use?
The TPA3255 stereo-board or the mono-channel one?
Hi Mike,
Cheers! I am new to this thread. I use the EVM with a differential input es9038q2m based modded dac.
My questions are:
1. Will there be sq benefit bypassing the opamps? I asked in the ti forum but did not get answers.
2. Can bypass be made with the 28pins Audio interface board socket? If so, which pins would correspond to the inputs?
3. In case bypass is a difficult job, do you think changing the ne5532 to a cleaner opamp like opa1612 result in better sq?
Regards,
Kay
If you have a real NE5532 this is a "cleaner" OP amp. Just be sure not to have a faked one, which is very popular. A "real one" is usualy around 1$ per piece in single or low numbers. Cheap OP amps are 2 Cent.
An expensive OPA or the like will hardly give audible improvement, if not compared on a system of highest quality from source to speaker.
They may even sound worse than the original one, if the surounding part´s values don´t comfort it.
An expensive OPA or the like will hardly give audible improvement, if not compared on a system of highest quality from source to speaker.
They may even sound worse than the original one, if the surounding part´s values don´t comfort it.
Hey Kay
I never tried using the Audio Interface Board inputs, as I don't have a source with diff outputs, but I know others have. @dubai200 ??? So I can't vouch for the sq benefit.
If you look at the EVM User's Guide (slou441), the schematic shows the AIB pins used.
Pins 11 and 13 for one diff input, pins 15 and 17 for the other diff input, and pins 21 and 22 for the grounds. I believe a solid 24 AWG wire can be pushed into the board for a good snug fit.
By doing so, you completely bypass the op amps. Only the 10uf coupling cap is between the source and the chip.
Hope this helps.
Mike