Finished Class D Amp TPA3116 2 1 Amplifier 2 50W 100 w AQ | eBay
Try this.
It's like work getting ebay links to obey... You have to cut out the text in the url after "itm" and just leave the number.
The amp is $42+$14 shipping to USA. Still "cheap as chips."
Another vendor has it for $58.56 with free shipping from HK.
http://www.ebay.com/itm/190896806176
Try this.
It's like work getting ebay links to obey... You have to cut out the text in the url after "itm" and just leave the number.
The amp is $42+$14 shipping to USA. Still "cheap as chips."
Another vendor has it for $58.56 with free shipping from HK.
http://www.ebay.com/itm/190896806176
Last edited:
Finished Class D Amp TPA3116 2 1 Amplifier 2 50W 100 w AQ | eBay
Try this.
It's like work getting ebay links to obey... You have to cut out the text in the url after "itm" and just leave the number.
The amp is $42+$14 shipping to USA. Still "cheap as chips."
Another vendor has it for $58.56 with free shipping from HK.
TPA3116 2 1 Completed in Case 50W 50W 100W Class D Amplifier Board | eBay
'62 people are viewing this item per day'.
Lot of interest out there.
have you done any frequency response sweep at any load to come to that conclusion?
Can someone with the uncased board please confirm the value of a resistor for me.
It is the one setting the gain of the sub amplifier, the left hand IC with the potentiometers at the front, on the side of the chip closest to the potentiometers.
From the left (pin1) there are 3 x 1u ceramic capacitors in a row, a 47K resistor, then a resistor marked on the silk screen as 75k (R21 on the TI data sheet, page 14). The one on my board is marked 8252 which is not 75k. I am not sure what this would do to the gain select circuitry internal to the IC but I am changing for the correct value of 75k.
I noticed this because I am trying to draw a schematic for the board. It appears to be basically the same as the 'typical application' on page 14 of the TI data sheet. The exceptions are the output inductor value and the snubber resistor.
It is the one setting the gain of the sub amplifier, the left hand IC with the potentiometers at the front, on the side of the chip closest to the potentiometers.
From the left (pin1) there are 3 x 1u ceramic capacitors in a row, a 47K resistor, then a resistor marked on the silk screen as 75k (R21 on the TI data sheet, page 14). The one on my board is marked 8252 which is not 75k. I am not sure what this would do to the gain select circuitry internal to the IC but I am changing for the correct value of 75k.
I noticed this because I am trying to draw a schematic for the board. It appears to be basically the same as the 'typical application' on page 14 of the TI data sheet. The exceptions are the output inductor value and the snubber resistor.
The resistor is 82.5Kohm. It's close enough to 75K to not make much difference.
SMD Resistor marking
SMD Resistor marking
I appreciate that in normal circumstances the exact value for setting the gain would not be too important. In the case of the TPA3118 the gain is determined by an internal ADC setting it to 20, 26, 32 or 36dB. The resistor tolerance should be 5% or better according to the data sheet, 82.5K is more than 5% adrift of 75k. This would apply the wrong voltage to the ADC input which may or may not be an issue depending upon the decision window.
The gain setting requires both R1 and R2 to be changed for the gain setting to be changed. If R1 is 47ohm it really does not matter if R2 is 10% off, even 20% won't be a problem as long as it's on the positive side it's off. YJ probably used 82.5K here because they wanted to use a higher tolerance part here meaning you save one tighter tolerance part.
So they probably figured that if they use one tight tolerance 47K ohm for R1 they can use a wider tolerance part for R2 by making it 10% higher value.
So they probably figured that if they use one tight tolerance 47K ohm for R1 they can use a wider tolerance part for R2 by making it 10% higher value.
The evaluation board circuit actually uses a tiny SMD trim pot for this resistor so you can set the gain at one of the discrete 4 settings. Cheaper to use single pot than 4 resistors 2 dip switches. There is wide margin in the resistor setting I would imagine. If you want adjustable gain try swapping out the resistor for a pot.
No not yet. I actually ordered the pot and when building the foam core amp I did not want to risk having the pot break off the glue which holds it to the paper face with tweaking the adjustment so I put a resistor in place. I should give it a try on Dug's PCB but find that the default 24 dB (?) setting is very nice and usable by both mp3 players and rca line out levels and has low noise on output.
I'm happy with the default gain too, but I will try the lower gain setting on one of them later on today to see how it sounds.
Gain on the YJ amp seems to be the maximum 36dB gain. Note that lowering gain will also affect input impedance and thereby the dc blocking high pass filter of the input caps.
I think the gain on the 2.0 version of the TPA3116 board is set to medium gain. Thanks for the input cap advice. I never tried the gain adjustment today... I was in power supply test mode all day today. Will probably try it tomorrow.
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If you have 2.1 and don't have a speaker connected to the sub output, you run the risk of damaging the output caps due to excessive voltage in the LC filter circuit. Connect an 8 ohm 25W or greater power resistor to the sub output. The OP ran into this with lower voltaqe rated ceramic caps. If the YJ caps have enough margin (2x voltage of PS), you are probably safe.
LOL Crisiti can't compete with that so I guess his prototype won't see light of day. Funny how these boards showed up just after we started asking Cristi about these chips. You'd think the vendors were monitoring these threads. Hmmm....
They would certainly be smart to do so...
I noticed that after the link to the eBay YJ board, the number of people viewing it on eBay really went up. The Aliexpress price just can't be touched by any small company trying to make these. They must have made a lot of units to get the price this low.
You have to offer more than just a bare bones amp to compete as competing on price is rather futile. There are other ways to make a more expensive product more appealing though.