I think some of people complaining about buzz and noise are experiencing a ground loop with PC/ntb. Fortunately TPA3116 offers balanced inputs which allow for complete elimination of the ground loop effects. It worked in my case Adding an Amp into Thin-Client PC
Thanks Dave, I'm still battling with a buzz that's evident at higher volume. I'll certainly try the battery option - I have a few 12V 7Ah batteries available for testing.
Is you your source grounded (PC/modern laptop)? Does your amp's power supply use ground/PE wire? If so, you may want to try connecting the amp with the fake single-ended outputs -> balanced inputs connection. That's what the balanced inputs are for - eliminating ground loop effects.
I'm using a fairly recent HP Pavilion laptop as the source, I assume it's grounded but I could be wrong.
The power supply for the amp is not grounded and I haven't checked where to connect ground - it's one of these:
AC Converter 110v 220v to 12V MAX 8A 100W Regulated Transformer LED Power Supply | eBay
Any specific reason why you're only using 12v? Most available boards can take 24v safely, with some considering 19v the sweetspot.
My error - I'm actually using the 24V version that looks pretty much identical.
I use a 24v version on some of my 3116's as well, hence my original question...
That combination should not produce a standard ground loop as the amp is not grounded. Still the Y-capacitor in the 24V PSU does leak quite a bit of noise. I can see it on my measurement results when my class-I scope is hooked to a class-II measurement computer - no "real" ground loop, yet the measurement gets way worse.
Even in this case I would try the SE-balanced connection. It may work surprises.
I recently bought 2.1 channel TPA3116D2 board, almost like this one:
New 2x50W +100W 2.1 Channel Digital Subwoofer Power Amplifier Board TPA3116D2 699903978280 | eBay
And it has a lot of buzz and hiss with any switching power supply, and if I connect it to old style transformer power supply, it all was gone, but since transformer was no go for me, I tried a lot of things, and finally found a solution - soldered 1uf ceramic capacitor with short leads directly to 4 and 8 pins of rightmost IC in 8 pin case (as shown on ebay listing picture). All buzz and hiss had gone now!
New 2x50W +100W 2.1 Channel Digital Subwoofer Power Amplifier Board TPA3116D2 699903978280 | eBay
And it has a lot of buzz and hiss with any switching power supply, and if I connect it to old style transformer power supply, it all was gone, but since transformer was no go for me, I tried a lot of things, and finally found a solution - soldered 1uf ceramic capacitor with short leads directly to 4 and 8 pins of rightmost IC in 8 pin case (as shown on ebay listing picture). All buzz and hiss had gone now!
CuriousOne, I agree that a radical way to reduce noise of class D + PowerSupply is a 60Hz trafo+diodes but not any SMPS so crappy as you expect yet. I have TPA3116 based 2-way(bi-amping) studio monitor project, with DSP ADAU1701 as a preamp, which has S/N = -104db(A) at tweeter output. The SMPS onboard is almost trivial quasi-resonant flyback with spike recuperation. I don't believe if 60Hz trafo, instead that SMPS, may improve S/N for single one db 😉
but mine has another issue, almost anecdotic - it acts like a mic! If I talk directly to PCB, I can hear my voice thru speakers!
12Vac/200VA will be more than enough. You can also go up to 15Vac/200VA and get more output power.
If you already have two 12Vac/200VA, what about connecting the secondaries in series (2x12Vac=24Vac -> 35Vdc rectified) and stepping the voltage down to 24Vdc with a linear regulator? Then, you have good margins for input voltage swings and can use the TPA3116 to its maximum.
No, a single rectifier bridge will do.
Transformer primaries in parallel, secondaries in series. If you phase the secondaries right you have around 24Vac out, if you phase them wrong close to 0Vac.
Transformer primaries in parallel, secondaries in series. If you phase the secondaries right you have around 24Vac out, if you phase them wrong close to 0Vac.
(35V-24V)*5A=55W of power wasted on linear regulator. Why you should do that?
For the power supplies for amplifiers, I usually hunt for transformers from old UPS-es. In general, they have two secondary windings with 7.5V AC and 5-15A current. Connect them in series and you will get 15VAC, which is about 20VDC and is great for most class D amps. If you can get UPS which used 24V battery, it will have 2x15VAC windings, which means you can use more powerful Class D amplifiers, which require +-20V and more voltage to operate.
For the power supplies for amplifiers, I usually hunt for transformers from old UPS-es. In general, they have two secondary windings with 7.5V AC and 5-15A current. Connect them in series and you will get 15VAC, which is about 20VDC and is great for most class D amps. If you can get UPS which used 24V battery, it will have 2x15VAC windings, which means you can use more powerful Class D amplifiers, which require +-20V and more voltage to operate.