Hi,
I've built an amp based on this module from ebay
New TPA3116 Class D Amplifier Board Bluetooth 2.1 Amplifier Board 100W+2*50W | eBay
Quite happy with the sound, I have it driving two Kenwood 4ohm coax units and an 8ohm 5x7inch woofer, although the bass seems a bit weak maybe because its supposed to be a proper subwoofer and the Kenwoods are a bit tinny, and too much high end so have to keep the 'treble' control on the unit right down.
My question is, does anyone know how to tap an auxiliary input into it? I have tried all the output pins of the Bluetooth module and the volume pot pins but get nothing. I'm a bit of a noob but have some electronics experience. I guess I'm missing something obvious.
Thanks for any help.
Theo
I've built an amp based on this module from ebay
New TPA3116 Class D Amplifier Board Bluetooth 2.1 Amplifier Board 100W+2*50W | eBay
Quite happy with the sound, I have it driving two Kenwood 4ohm coax units and an 8ohm 5x7inch woofer, although the bass seems a bit weak maybe because its supposed to be a proper subwoofer and the Kenwoods are a bit tinny, and too much high end so have to keep the 'treble' control on the unit right down.
My question is, does anyone know how to tap an auxiliary input into it? I have tried all the output pins of the Bluetooth module and the volume pot pins but get nothing. I'm a bit of a noob but have some electronics experience. I guess I'm missing something obvious.
Thanks for any help.
Theo
I have it's bigger brother, the 4.1 board but it comes with an AUX analog input so I'm sure it's possible as long as you find the correct points. If I get a chance, I'll check mine to see if the AUX input connects to any of the BT pins or how it's wired in general.
I surprised your board doesn't have one.
I surprised your board doesn't have one.
Thanks very much, that'd be great. Yes I only noticed the 'bluetooth only' warning after I bought it. I think there is a lowpass filter on tge stereo channels and the bass is very deep so it sounds like its missing the mid-bass range. I need to get a diagram of the position of the components to change.
Thanks,
Theo
Thanks,
Theo
Not sure if adding a line in is going to work out but if its going to work at all I think you need to tap in after the SGM358 op amp, just before the main volume control where the left and right signals pass through the two 1K resistors. Not sure where to pick up the ground lead, but it should be easy enough to figure out. The ground is common for L&R at that point.
Have you noticed a background noise when the volume is low? I like this 2.1 amplifier except for that annoyance. I believe the subwoofer channel crossover point is at 150hz and the stereo channels run full range. What size and type of enclosures are your drivers mounted in? Those being car audio speakers they are likely designed for infinite baffle use (in other words, relatively large enclosures). Also, I think this amp does best with at least a 19v 4a power supply. I'm using this amp to drive a ported 4.5" woofer and two sealed 3" full range with great results (except for the background noise!).
Have you noticed a background noise when the volume is low? I like this 2.1 amplifier except for that annoyance. I believe the subwoofer channel crossover point is at 150hz and the stereo channels run full range. What size and type of enclosures are your drivers mounted in? Those being car audio speakers they are likely designed for infinite baffle use (in other words, relatively large enclosures). Also, I think this amp does best with at least a 19v 4a power supply. I'm using this amp to drive a ported 4.5" woofer and two sealed 3" full range with great results (except for the background noise!).
Reading another thread it looks like you are right, after the opamp but the lines need to be switched off from the opamp by the input jack. I will try that next.
My enclosure is quite big, 40cm deep by 50 high with a baffle between bass and car speakers and two 3cm vents at the back. My bass speaker is a 7x9 unit. I think for me the 150hz crossover is too low.. would like to try raising that if I can find the filter. Mine is a portable, with two 12V 4Ah batteries in series.
There is some noise for sure but only very high hiss that I think comes from the Bluetooth. Hoping it'll go away with an line in.
My enclosure is quite big, 40cm deep by 50 high with a baffle between bass and car speakers and two 3cm vents at the back. My bass speaker is a 7x9 unit. I think for me the 150hz crossover is too low.. would like to try raising that if I can find the filter. Mine is a portable, with two 12V 4Ah batteries in series.
There is some noise for sure but only very high hiss that I think comes from the Bluetooth. Hoping it'll go away with an line in.
Do you have the thiele/small parameters for the woofer? Without those or some enclosure design guidance from the speaker manufacturer it will be difficult to come up with an optimum enclosure type, internal volume, and port size and length if doing bass reflex. If your woofer is a 5x7, 6x8 or 6x9 car audio speaker it was likely optimized for using the car trunk as an enclosure.
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No, sadly no info on the speaker, but it is from a similar portable PA system. It was a coaxial but the midrange was fried from a previous unit's crossover shorting so I took out the mid and tweeter and I am just using the woofer (yes probably 6x9). The only info on it is 'Chiayo 8ohm'. I don't think its the enclosure because it also sounded too tinny before the speakers were enclosed. The stereo channels are on these: Kenwood 5x7" 3 Way Speakers KFC-PS5795C - Supercheap Auto
So this is weird... cut the lines from the opamp output from the BT module, connected a jack, and when its turned on it plays for about a second then cuts out. Tried a 10k resistor and a 100uf cap, and both, but get same thing.
????
Must be some protection switch on the amp to cut off if the bt is not connected? How to defeat that?
????
Must be some protection switch on the amp to cut off if the bt is not connected? How to defeat that?
There is a circuit driven by pin 1 of the Bluetooth module that controls the mute function on the TPA3116 amplifier chips (pin 12 on each). I don't know why it would be unhappy but maybe you need a dummy load on the left and right output of the op amp? There is also short circuit protection on those TPA3116 chips so check your speaker wires too. I'd probably reconnect the BT and get a different amplifier at this point as this is getting in deeper than I would recommend.
The 6x9 you have likely came from a Chiayo Dynasty portable PA system. I can't find a decent photo but I don't see any ports on it unless they were hidden behind the grille. If you have the original cabinet just copy it. The overall dimensions of the Dynasty would suggest about a 18 liter sealed enclosure. The Dynasty was spec'd down to 50hz so it's not going to give you the low end the subwoofer portion of that amp can give.
The Kenwoods you have are rated to 80hz. In the right size enclosure (big like a car trunk) they should play loud and sound pretty decent on their own with a 2 ch amp. But they won't do much below 150hz if confined to a small space. It might be interesting to give all of your cabinet space to the kenwoods (with no ports) and see how they do then.
The 6x9 you have likely came from a Chiayo Dynasty portable PA system. I can't find a decent photo but I don't see any ports on it unless they were hidden behind the grille. If you have the original cabinet just copy it. The overall dimensions of the Dynasty would suggest about a 18 liter sealed enclosure. The Dynasty was spec'd down to 50hz so it's not going to give you the low end the subwoofer portion of that amp can give.
The Kenwoods you have are rated to 80hz. In the right size enclosure (big like a car trunk) they should play loud and sound pretty decent on their own with a 2 ch amp. But they won't do much below 150hz if confined to a small space. It might be interesting to give all of your cabinet space to the kenwoods (with no ports) and see how they do then.
Thanks for the info.
I don't think its a cabinet or speaker problem not having enough bass on the stereo channels, I think its just the filter / crossover design of the board. It still sounds good except for the BT noise but I can live with that. What I'd really like is to be able to adjust the sub bass to allow a bit more mid to it and vice versa for the stereo channels. I know ppl do these mods but got no idea where to start on this board.
Given up on the aux input.. any tinkering just makes it cut out.
Ta.
I don't think its a cabinet or speaker problem not having enough bass on the stereo channels, I think its just the filter / crossover design of the board. It still sounds good except for the BT noise but I can live with that. What I'd really like is to be able to adjust the sub bass to allow a bit more mid to it and vice versa for the stereo channels. I know ppl do these mods but got no idea where to start on this board.
Given up on the aux input.. any tinkering just makes it cut out.
Ta.
For anyone interested, I have managed to make the stereo channels more bassy. I changed the filter components (next to the volume control - two 100nF caps and two 39k resistors) to 200uf caps and 22k resistors. I'm not sure why but this raised the tone of the sub bass and gave the stereo more bass.. so quite happy now except for still having no aux and the BT being a bit noisy. Cheers all.
Hi, I just got it to work today, and it is pretty easy job, first you need to cut off signal from op amp SGM358, because you can burn your sound card. Signal from op amp is DC offseted and is about 1.5V on each channel. Then you place your input signal cable before 1K ressistors. You put ground wire on the ground of the PCB, best place for me was as shown in the picture, near potetiometer I scratched PCB and solder it there, for everything to work you need to bypass marked Y1 NPN SOT23 transistor that is enable signal for the TPA3116, signal comes from bluetooth module when sound module says that audio is present and puts about 1.7V in the transistor base and activates the enable signal of 5V on the amp, here are pictures, it's all soldered just temperarly till I get the case for the board and make a switch that changes input signal to amp bluetooth/aux.
Notice:
Double check your connection, solders, make sure that no voltage is present on the input signal cable with a multimeter. I'm not responsable if someone damages their amp or audio source device
Notice:
Double check your connection, solders, make sure that no voltage is present on the input signal cable with a multimeter. I'm not responsable if someone damages their amp or audio source device
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