TPA3116D2 Amp

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radiosmuck

Banned
Joined 2012
millstonemike said:
I don't see the Bluetooth circuit in the pic. There is this same board with Bluetooth added on. Another user has had bad experience with this board and the Bluetooth daughter board (lots of squealing, etc.). I'll try to dig up those posts tonight and relay them on.

My experience and analysis has been that the three volume controls are just that: L-R volume, Sub volume and overall volume. Every once in a while I come across a advertisement for this and similar boards that say the sub pot adjusts the sub x-over freq. I believe that those statements are just wrong.
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I purchased the same 2.1 board (no BT) a while back and did not like it, it sounded very muddy and the pots interfere with each other, as if they are ganged together.
I have ordered the following,
YJ dual AC12V 0 12V NE5532 tone board Amplifier preamp mixer board Pre amplifier preamplifier for 2.1 channel amplifier board-inOther Consumer Electronics from Consumer Electronics on Aliexpress.com | Alibaba Group
and also a IRS2092 200w mono board for the sub with a 3116 stereo board
 
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clengman

Member
Joined 2011
doctormord said:
VOltage drop of <2%, i wouldn't adress this to be a real concern/issue. Additional hf-decoupling might help a bit at high volumes and EMI-wise, but, looking at the picture, implementing so is a bit tricky, as it may colide with the heatsink.

Those thin tracks are really not optimal but at low/medium volume i don't see a problem here. It's just some increased track-resistance/impedance - still small compared to the speakers resistance/impedance. They just heat up more than widther traces.

To be honest, i'd leave it as is if it works. Rolling caps is up to you, don't see a real advantage here.
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I've had a lot more time to listen to the amp and play around. It depends a lot on the music I'm playing, but I notice that the problem I first described is still present. It sounds like the amp is straining when playing loud, dense music. (Sparse music sounds very nice.) HOWEVER, it seems to be much worse when I use my computer as a source compared to my smartphone. When I use my phone as the source, the volume is lower, but it sounds much nicer. Could this be a matter of mismatched impedance/incorrect gain setting when I use my computer as the source? My gain resistors are 20kohm and 100kohm for 26dB.

What I'm reading on the data sheet about impedance and gain settings is counterintuitive to me. I would think that if the source impedance is too low (signal too strong) that I would want to reduce the gain setting, but it looks like higher input gain goes along with lower input impedance.

If the problem is a source with impedance that is too low, is the answer to change to the highest gain setting so that input impedance is closer to source impedance? Or am I thinking about it all wrong. Thanks!
 
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Buehgemeiste

Member
Joined 2013
clengman said:
I've had a lot more time to listen to the amp and play around. It depends a lot on the music I'm playing, but I notice that the problem I first described is still present. It sounds like the amp is straining when playing loud, dense music. (Sparse music sounds very nice.) HOWEVER, it seems to be much worse when I use my computer as a source compared to my smartphone. When I use my phone as the source, the volume is lower, but it sounds much nicer. Could this be a matter of mismatched impedance/incorrect gain setting when I use my computer as the source? My gain resistors are 20kohm and 100kohm for 26dB.

What I'm reading on the data sheet about impedance and gain settings is counterintuitive to me. I would think that if the source impedance is too low (signal too strong) that I would want to reduce the gain setting, but it looks like higher input gain goes along with lower input impedance.

If the problem is a source with impedance that is too low, is the answer to change to the highest gain setting so that input impedance is closer to source impedance? Or am I thinking about it all wrong. Thanks!
Click to expand...

Yesterday i played around with different potentiometers and hf filters at the inputs of a 3118 board.
I found a mono summer via 15K resistors, an A5K pot and filter of a 330R in series and a 1nF cap to ground having nice noise surpressing effects.
 
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clengman

Member
Joined 2011
Buehgemeiste said:
Yesterday i played around with different potentiometers and hf filters at the inputs of a 3118 board.
I found a mono summer via 15K resistors, an A5K pot and filter of a 330R in series and a 1nF cap to ground having nice noise surpressing effects.
Click to expand...

I'm using this one in stereo. I've never had any issue with noise (as in hissing) with this amp. If I plug it in to my source and turn the volume all the way up it is silent.

One thing I notice very clearly is that low/mid frequency noise at the beginning of some remastered digital tracks is really accentuated, but then goes away when the instruments come in. BUT I don't notice this at all if I use my phone as the source playing the same track.

I also feel that the amp makes a nice balanced sound when the instrumentation is sparse, but when the instrumentation is very dense, I lose a lot of lows and mids. Once again, this doesn't seem to be the case if I use my phone as the source instead of my computer.

I tried turning the volume down on my computer. Changing the source volume seemed to have no effect on the output volume whatsoever until I got to extremely low source volumes. Then dynamics sounded a little better, but I had lost most of the high frequency range, sounded very muddy.
 
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clengman

Member
Joined 2011
irribeo said:
If I remember correctly you also ordered a Sanwu3118. Try that one. Take your stereoboard as is or burn it was advise given by two other posters. I feel there is too much wrong with design to even think about what causes what.
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Yes I have a 3118 coming. It's for something else, though. If it sounds good. I might get two more and run them in stereo for my computer speakers.
 
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clengman

Member
Joined 2011
Right. There's one on the board. I've tried at various volumes on the pot. Doesn't help.

Using PC as source, with volume pot at 1/2, output from speakers is similar to when I use my phone as source with the volume pot at full. The difference is the PC sounds terrible, (no low and mid and weird high end with dense instrumentation) and the phone sounds fine (nice balanced frequency response).
 
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irribeo

Member
Joined 2013
Gainsetting is 36dB for 3118, so that could cause problems, but could be different problem.

I think if you feel like spending time on 3116 you could shortcircuit one channel on white input plug, listen and short the other channel and listen. If bootstraps have any influence on 3116 behavior, Lchannel will be worse.
 
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clengman

Member
Joined 2011
I really do appreciate all the advice. I'm asking as much just to build a little better understanding generally as I am to get this particular amp working. I'm trying to do some reading on my own as well.

I ordered a big box of single AA battery holders a while ago and am waiting for them to arrive from China. I'm planning to use them with the NiMH batteries I always have around the house to wire up test batteries. I'll definitely try the 3116 with a battery (I suppose at a few different voltages) to see what happens.

irribeo - I'm reading about bootstrap circuits. I'll try what you suggested.
 
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