Hello,
I'm trying to use this cheap ebay TPA3116 board for a project I'm working on I'll be building quite a few of the resulting systems, and simplicity is more important than pure sound quality.
Overall, this board is exactly what I'm looking for. Perfect size, perfect output, etc. My problem is, as with every other TPA3116 board I've tried, when I try to move the volume control off the board, I get a lot of hiss at low volume levels. This hiss is NOT present when the on board volume control is used.
The on-board volume control is just a 50k dual pot. I'm sure not the greatest quality. The off board volume control is also a 50k dual pot. Both give the same amount of volume control but the off board control is noisy, by a big margin. Is this just noise being picked up from the short length of wire to the board, or could I be missing something? I'm shocked at the difference. I've moved the wire around to make sure it's not near the power supply or anything, but nothing makes a difference.
Any thoughts?
I'm trying to use this cheap ebay TPA3116 board for a project I'm working on I'll be building quite a few of the resulting systems, and simplicity is more important than pure sound quality.
Overall, this board is exactly what I'm looking for. Perfect size, perfect output, etc. My problem is, as with every other TPA3116 board I've tried, when I try to move the volume control off the board, I get a lot of hiss at low volume levels. This hiss is NOT present when the on board volume control is used.
The on-board volume control is just a 50k dual pot. I'm sure not the greatest quality. The off board volume control is also a 50k dual pot. Both give the same amount of volume control but the off board control is noisy, by a big margin. Is this just noise being picked up from the short length of wire to the board, or could I be missing something? I'm shocked at the difference. I've moved the wire around to make sure it's not near the power supply or anything, but nothing makes a difference.
Any thoughts?
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Hi,
As seen elsewhere on this forum, and from my own experience with TPA3116, to reduce noise you need a buffer after the pot.
Hope this helps.
As seen elsewhere on this forum, and from my own experience with TPA3116, to reduce noise you need a buffer after the pot.
Hope this helps.
Thanks. For some reason that solution didn't come up in my search. Makes sense but kind of stinks as it will be a tough solution to implement in the small space I have to work with.
Ok, now I've tried a buffer after the volume control and that didn't help at all. In fact it increased the noise just a bit.
Yes, I've tried it with the pot still on the board as well as with it removed and bypassed. Either way there is a distinct hiss when using the off-board volume control.
Yes, I've tried it with the pot still on the board as well as with it removed and bypassed. Either way there is a distinct hiss when using the off-board volume control.
I've never used the TPA3116 so I don't know if this is causing the problem, but the typical application diagram shown on page 26 of the TPA3116 datasheet indicates that the L and R signal input returns are separate (TI refers to those connections as IN_N_RIGHT and IN_N_LEFT) . Perhaps the external pot you're using has them connected together inside the small enclosure?
Sometimes I tie them together and sometimes I keep them separate and I've not had any issues. But I've never used this device.
Sometimes I tie them together and sometimes I keep them separate and I've not had any issues. But I've never used this device.
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Try a 10K pot? there's been some discussion about on-board pot values in the mammoth TPA3116 topic. Relating to the "dual chip" board.
The on-board pot is 50k and it's completely silent. I'll try a 10k, but it doesn't appear to be the pot, just the location of the pot
Most TPA boards have way too much gain. I an not see it on the picture but please check gain settings. TPA boards sound best and are least susceptible to hiss with 20 dB gain setting. Many are set to 36 dB. Please check datasheet. When reducing gain input impedance becomes higher which is OK when a 50 kOhm potentiometer is used.
The 20 dB gain is enough with "normal" sources. I can't tell anything about smart phones as I don't use those for audio.
The 20 dB gain is enough with "normal" sources. I can't tell anything about smart phones as I don't use those for audio.
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