Reading reviews here is a bit iffy. At the very start of this thread the stock amps were wonderful, now they require major part changes and different coloured boards.
Fortunately, getting sucked in is not expensive.
I'm waiting for the tartan board. :-D
Fortunately, getting sucked in is not expensive.
I'm waiting for the tartan board. :-D
Is it inappropriate to discuss modifying boards on a DIY site?
As you note, they are cheap.
Working on them obviously brings many of us enjoyment. While I would count myself as relatively ignorant, I have learned a great deal from these projects.
Please explain why you are troubled by people doing what they will with their own property. I am honestly and truly baffled by it.
As you note, they are cheap.
Working on them obviously brings many of us enjoyment. While I would count myself as relatively ignorant, I have learned a great deal from these projects.
Please explain why you are troubled by people doing what they will with their own property. I am honestly and truly baffled by it.
I am as well... there are plenty of threads on this forum where I don't share the same interest and enthusiasm and I spend zero time reading and posting in them.
Some get sucked in and comment on threads even if they contribute nothing.
Others just like playing with amplifiers.
My Wife loves blue, so I think I'll get some of the blue boards. That way they will for sure sound like an improvement to her.🙄
On a more serious note I'm concerned about the difficulties people are having with driving these boards from the computer's soundcard. For my active system I will need 8 channels/4 stereo amps. Would hate to have to put some kind of preamp stage in front of the amps. I have an Asus Essence ST with H6 daughter card. Anybody here using one of these boards (any color) with an Asus soundcard? Also the new blue boards don't have a volume pot. Wonder if that might help on the soundcard problem?
Cheers,
Rod
On a more serious note I'm concerned about the difficulties people are having with driving these boards from the computer's soundcard. For my active system I will need 8 channels/4 stereo amps. Would hate to have to put some kind of preamp stage in front of the amps. I have an Asus Essence ST with H6 daughter card. Anybody here using one of these boards (any color) with an Asus soundcard? Also the new blue boards don't have a volume pot. Wonder if that might help on the soundcard problem?
Cheers,
Rod
As an audio and electrical newbie I just want to see how you have all those caps wired up! Sounds like something interesting to try out. Would increasing # of caps increase ripple current? Perhaps I could achieve better bass response with multiple lower value caps or just multiple 25v 1000uf ones.
You are correct since different people have slightly different perception to sound. You cannot rely on review only. What sounds good to me may be just so-so for you. However, if a number of people, who use the amp in different setups, and likely have different tastes reported favourably, then it is probably worth a try. Still, there is no guarantee that you will like the sound. As you have pointed out, the boards are cheap, just get one and try it.
I recalled that most people like the sound of the stock board. Some try to "improve" the sound quality further by replacing some of the parts. It is not necessary to mod the board in order to get decent sound.
The boards from YJ are all red. Other manufacturers try to differentiate their design from the YJ boards and uses different colours. I looked up the ads in Taobao and confirmed that the two green and one blue boards are from three different shops. Based of the comments of some posters, the non-red boards seem to be of better design.
Regards,
One possible solution for the soundcard source distortion issue would be to install an input transformer with balanced output wiring directly to the + & - amp inputs for each channel.
Often an isolation transformer works nicely to prevent noise from a PC audio output reaching an amplifier, and with these class-d amps another benefit is the bypassing of the two ceramic(?) input coupling caps.
I've done exactly this with the Sure TPA3110D2 board (except the transformer is actually a TVC preamp) and it sounds much better than the standard setup of dual ceramic coupling caps and - input tied to ground.
I'm awaiting delivery of the green TPA3116 board and plan on making a similar modification.
Often an isolation transformer works nicely to prevent noise from a PC audio output reaching an amplifier, and with these class-d amps another benefit is the bypassing of the two ceramic(?) input coupling caps.
I've done exactly this with the Sure TPA3110D2 board (except the transformer is actually a TVC preamp) and it sounds much better than the standard setup of dual ceramic coupling caps and - input tied to ground.
I'm awaiting delivery of the green TPA3116 board and plan on making a similar modification.
Interesting.... I need it! Can you elaborate a little bit? Maybe a little schematic could help.
I'm travelling right now so can't provide a schematic (yet). As I said I've done this to the TPA3110D2 board but I believe the process should be pretty much the same with the TPA3116 boards.
- select a suitable input transformer (ideally chosen to suit the amp input impedance, which depends on that gain setting of a particular implementation, but I think is typically 30Kohm for 26db gain. Alternatively just grab any old 600ohm isolation transformer as this will prove the solution works as required)
- check the datasheet for the specific amp chip. Identify the + and - input pins for each channel. These are usually biased at +3V and shown on the application diagram with 1uf input coupling caps.
- connect the primary side of the transformer to the balanced or unbalanced source (both are possible)
- remove the 4x input coupling caps on the amp board (+& - for each channel) and connect the transformer secondaries to the pcb pads previously used by the coupling caps and connected to amp input pins (one transformer secondary connects to + & - of one channel).
- experiment with ground connections between source and amp board (connection or disconnection may provide lowest noise - hard to predict)
I'll take photos in a week or two after my TPA3116 board arrives.
- select a suitable input transformer (ideally chosen to suit the amp input impedance, which depends on that gain setting of a particular implementation, but I think is typically 30Kohm for 26db gain. Alternatively just grab any old 600ohm isolation transformer as this will prove the solution works as required)
- check the datasheet for the specific amp chip. Identify the + and - input pins for each channel. These are usually biased at +3V and shown on the application diagram with 1uf input coupling caps.
- connect the primary side of the transformer to the balanced or unbalanced source (both are possible)
- remove the 4x input coupling caps on the amp board (+& - for each channel) and connect the transformer secondaries to the pcb pads previously used by the coupling caps and connected to amp input pins (one transformer secondary connects to + & - of one channel).
- experiment with ground connections between source and amp board (connection or disconnection may provide lowest noise - hard to predict)
I'll take photos in a week or two after my TPA3116 board arrives.
I use the Sure TPA3110D2 amp board, so if you can provide a schematic for your use of input transformers, I would really appreciate it. I'm sure others who use the TPA3110D2 amp would too.
No problem, will provide photos and a schematic when I get home. I'm in Amsterdam right now so will probably need a day or so to recover. Should be productive again on Sat/Sun 🙄
Okay my design is ready for fab. 🙂
I can see this project costing me around $200+ to get 2 boards assembled. I'll be loading the BOM into Mouser later and can give you, the one of comp costs.
When you put a fair bit of time/effort into something, you want to avoid this if you can. Sounds like music downloading to me.
I guess the only way is to not release the gerber/fab data, like what ESP does.
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Your projected cost to build one amp would be 100+ $? That' quite a bit higher than I thought for a small D-amp that requires no heat sink and big trafo.
I think that would work.
Regards,
Are you using SMPS? (They don't have ripple like a linear) More uf means less ripple, more a available current. Capacitors are usually much faster than the average SMPS, and at high enough values will change the response from SMPS (but it's preferable ultimately).
The smaller value caps (uf) behave better, but there are obvious limitations to how much any one person is going to try to solder together, in a given space.
They are all just wired in parallel, as close to DC input as manageable. You can get hole island pcb, or just solder stripped wires, whatever. Reducing distance and lead length is best, after attaining a good uf amount.
I loaded the BOM into Mouser project manager, that is what the parts cost are roughly, $100 including the case which is $20 alone.
This is a TPA3116 PA that can be used as a sub woofer amp (summer/lpf/pbtl config) or a 2-channel stereo amp.
The TPA3116D2DAD costs $5.65, in single qty.
TI sells their TPA3116D2EVM for $CDN 181.61, without a case, so I am about 1/2 of what they sell theirs for. I have upgraded components and additional features.
http://ca.mouser.com/ProductDetail/...116D2EVM/?qs=sGAEpiMZZMtVeuWkqeJ8IMlM21ksU2b/
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Im using a linear power supply. I just dont quite understand the relationships here which could just be chalked up to my non electrical background. I guess my misunderstanding is should I try 10 100uf caps or 10 1000uf caps...or are 10 100uf caps any different than a single 1000uf cap and so forth. Maybe im just getting bogged down but since you mentioned a noticable diference in sound with your multi cap setup I figured that sounded promising especially since there seem to be mixed opinions about the real audible sonic improvements to be gained by changing components. I cant recall that many posts where someone discussed changing a component and noticing a difference.
@rsavas
Is your board for testing purpose only? Otherwise, I don't consider a good idea placing the power connector at the same side of (and so close to!) the volume pot 🙄
Is your board for testing purpose only? Otherwise, I don't consider a good idea placing the power connector at the same side of (and so close to!) the volume pot 🙄
Bulk caps, if needed, can and should be placed close to the power terminals, or even off board.
The decoupling caps should be as physically close to the chip as possible to minimize the current loop, and thereby lowering the ESL. This is of vital importance to the function of the decoupling caps. I highly suggest you do not place very large capacitors, physically or in capacity, in place off the 220µF decoupling caps suggested by TI, although you can go higher in capacity for those (up to about 1000µF) if needed to achieve the required ripple current handling capacity, and you can have several in parallel if needed to achieve lower ESR. However, always observe that the current loop is as short as possible thereby lowering the ESL as much as possible.
Also, for the smaller ceramic decoupling capacitors, I suggest using 1210 or 0805 types instead of 1206 types, as these have inherently lower ESL due to the physical size. You can even try to find 0612 types (1206 types with termination on the long sides), although those are rare in the voltages required.
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I have one of these on order, I'm sure a little knob twiddling will effect the sound more than a few replacement parts.
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