It will not be 55W because the voltage will sag somewhat from loading. Let's guess, down to 32V (at 5Arms). Then, it would be 40W IF you use a constant amplitude sine-wave at the amplifier input and let it drive the amplifier close to the clipping point.
With music and taking the crest-factor of music into account, you will rather have an average current of some 1Arms IF you play very loud. That will then leave some 10W loss in the series transistor.
You are absolutely right in that you adapt your power supply according to which components you have at hand. Old UPS transformers sounds like a good idea. I also re-use old transformers. Here, we already have two 12Vac transformers and they can be used for a linear supply.
When you design a linear supply, your input voltage has to be high enough to take account of:
the necessary regulation voltage drop,
ripple at the input storage capacitors,
rectifier forward voltage drops,
sagging of the transformer voltage from loading and,
variations in the grid voltage.
Then, you quickly end up with more than 5V drop. This is the inherent disadvantage of linear power supplies. In return, they can be designed for little ripple and noise and with a very fast load response.
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I'm testing a dual amp setup, fed by a dirt cheap external USB sound 'card' that allows me to use EQ APO as a crossover.
I'm using one stereo 3116 module and a separate 3116 mono module, both powered off the same PSU. I've managed to invoke a mosquito-like buzz, which I gather is a direct result of both modules sharing the PSU. Apart from the obvious solution of using two PSUs, is there another way of eliminating this buzz?
I'm using one stereo 3116 module and a separate 3116 mono module, both powered off the same PSU. I've managed to invoke a mosquito-like buzz, which I gather is a direct result of both modules sharing the PSU. Apart from the obvious solution of using two PSUs, is there another way of eliminating this buzz?
I can draw a diagram but it will take me a while. I'm certain it is a consequence of using the same PSU: all I do is remove the (shared) power input to the stereo amplifier and use a separate PSU, and the buzz is gone.
I recall reading of this issue, I think it is well discussed in the 3118 thread.
The chip datasheet shows power supply ripple rejection ratio of at least -60dB. IMO that is a decent value.
IMO again you are hitting a ground loop effect - a loop between the two amps and a single PSU - the input 0V terminals are connected, the 0V supply terminals are connected - creating a nice loop.
Again, 2 cents I would try using the balanced inputs on both amps, connecting the balanced-line shield to GND on the amp sides. That should turn the ground loop noise into common-mode noise which the differential inputs should eliminate. It will cost nothing to try.
IMO again you are hitting a ground loop effect - a loop between the two amps and a single PSU - the input 0V terminals are connected, the 0V supply terminals are connected - creating a nice loop.
Again, 2 cents I would try using the balanced inputs on both amps, connecting the balanced-line shield to GND on the amp sides. That should turn the ground loop noise into common-mode noise which the differential inputs should eliminate. It will cost nothing to try.
Thank you. I have some shielded cable here so I'll make up leads for both amps and try it a little later today, Should I ground the shield at the PSU end as well, if so, where exactly on the PSU? I posted a link to the type of PSU a few posts back.
Grey unplugged cable to the right is the supply for the stereo amp from the PSU, shared with supply for the mono amp. The stereo amp as shown in this photo is powered by a separate PSU that is out of shot. Like this, there is no noise, but as soon as I use power from the shared PSU I get a high pitched buzz.
https://www.diyaudio.com/forums/attachment.php?attachmentid=704726&stc=1&d=1537530745
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I have the same PSU and powering 2 boards for 4 channel setup. After it is switched on and the signal level is low, then it is OK. But if I increase the volume and then mute the sound - there is whistle noise in the speakers. If I power the amp modules from a analogue regulated PSU - there are no problems at any sound levels.
When I resolve this problem, I will report.
When I resolve this problem, I will report.
Any idea where to find a ground point on this PSU? - both amps are grounded so I'm wondering whether it will help to ground the PSU.
Now I've looked at your picture...
1. Remove the Ground/Earth white cable from the entire setup. If you want to use it - connect it to the "-" output of the PSU!
2. Rearrange the amplifier boards, so the power connectors to be as close to the PSU as possible. Use thick and short cables from the PSU to the amplifier boards!
1. Remove the Ground/Earth white cable from the entire setup. If you want to use it - connect it to the "-" output of the PSU!
2. Rearrange the amplifier boards, so the power connectors to be as close to the PSU as possible. Use thick and short cables from the PSU to the amplifier boards!
I can rearrange things so that power leads from the PSU to amps are as short as possible. The ground/earth white cable that you see in the photo is connected on the other end to mains earth, so is it safe to connect this to PSU "-" output?
My amp finally arrived, so I post experiences with this AIYIMA version, if nobody encountered it yet.
Aiyima TPA3116 2.0 Digital Amplifier Board Amplificador 50W*2 Support PBTL Parallel Mono Model 100W DC12 24V-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
TPA3116 chip have some white thermal grease applied.
I have set it in PBTL 1x100W mode by connecting (and disconnecting) switch points on PC by soldering, according to infro from seller.
It have SMD blue LED on PCB, but there are points for soldering your own LED.
When powered up, there is no pop, it will remain muted for about 2secs.
When set to 26dB gain, there is also no hearable hiss or buzz.
When set to 32dB, there is some quiet buzz, which goes stronger as volume knob closing to 50%, then it starts to get quieter again...its strange, does anyone know why? I thought, that the buzz will get louder as I move volume higher.
Tried it with some 20W speaker, it can do pretty loud sound.
But so far, I have only 19V/3.5A power brick to test with. Another one 24V/6A is on the way.
Playing some electronic music for about 30mins, heatsink remains cool. Only when I tried some bass test tracks, and volume set to 75%, it get just lukewarm.
Aiyima TPA3116 2.0 Digital Amplifier Board Amplificador 50W*2 Support PBTL Parallel Mono Model 100W DC12 24V-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
TPA3116 chip have some white thermal grease applied.
I have set it in PBTL 1x100W mode by connecting (and disconnecting) switch points on PC by soldering, according to infro from seller.
It have SMD blue LED on PCB, but there are points for soldering your own LED.
When powered up, there is no pop, it will remain muted for about 2secs.
When set to 26dB gain, there is also no hearable hiss or buzz.
When set to 32dB, there is some quiet buzz, which goes stronger as volume knob closing to 50%, then it starts to get quieter again...its strange, does anyone know why? I thought, that the buzz will get louder as I move volume higher.
Tried it with some 20W speaker, it can do pretty loud sound.
But so far, I have only 19V/3.5A power brick to test with. Another one 24V/6A is on the way.
Playing some electronic music for about 30mins, heatsink remains cool. Only when I tried some bass test tracks, and volume set to 75%, it get just lukewarm.
Your intuition is logical. When you put the potentiometer in the middle position, the TPA3116 amplifier looks into the highest impedance towards the source. Amble experience shows it then generates hiss. In the middle position, connect 4K7 from the potentiometer output to ground and the hiss is gone.
