Recently I needed to replace a failed SW plate amp. I bought a combo digital amp + switched PSU New Assembled High-Power 280W Digital HIFI Subwoofer Amplifier Board Black+ Q9P9 192090130320 | eBay . The board was rather noisy. After splitting the amp-psu board and moving the PSU away from the amp into a separate enclosure, the combo is dead silent now. Just 2 cents, but I would not trust the switched PSU being so close to the sensitive digital amp.
Quick noob question, please. The gain set by R1 & R2 is power gain or voltage gain? I removed R2 to reduce the gain to 20dB in a guitar amp that uses this 3118 as the power amp. The supply voltage for the power amp is 20V. The preamp is built with a couple TL082 opamps at 9V. So I reckon I can get about a 7 to 8V voltage swing in the preamp before it distorts. With those 20dB in the power amp, what will be the signal amplitude at the output of the 3118?
Chris has his mathematics ready even in the morning. I not.
20dB is 10 times. With a 20V supply for the 3118, it can maximum reproduce a 2V (peak) input signal. For anything above, the 3118 output signal will be clipped.
Chris brain is working well even on a Sunday morning.
If the guitar delivers too high a signal, you have to adapt the gain in the TL082.
Thanks guys. I see, anything over a 2V peak (4V peak to peak) input signal (preamp output) and the 3118 @ 20dB and 20V supply will be about to clip because 20 log(20V/2V) = 20dB.
2V= Vinput_clip = 20V / (10^(20dB/20)
So I guess the dB figures in the 3116/8 datasheet actually refer to voltage gain, right?
2V= Vinput_clip = 20V / (10^(20dB/20)
So I guess the dB figures in the 3116/8 datasheet actually refer to voltage gain, right?
thanks you for the roses.....dezember is off - saison (biking..) so i am in flame for audio....but still the oscillation problem on my tpa3255
....another story...thanks you for the roses.....dezember is off - saison (biking..) so i am in flame for audio....but still the oscillation problem on my tpa3255
Chris, biking in December?! It's a mistake. You don't bring out the presents for the children by bike, you use rain-dears. In December the authorities throw a lot of salt on the roads and that salt go in your bicycle chain and ruins it in short time. Rain-dears do not have chains and anyway they know how to fly so they don't even touch the road. You better get back in your lab.
I will try to look at the oscillation problem. A slight problem with the TPA3255 thread is the speed at which things happen. New components go in a board and leaves the board faster than it takes to heat up an oscilloscope. Such makes it difficult to know the actual configuration.
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@biking
i am generally a MTB er so dirt and dust and other things i don not care during biking
...after every trip i clean my chain and derailleur... (6500 km and about 100.00 updhill )yes i know ....just intensive working on the weekend for audio..........but feel free to punish me in the tPA3255 thread if i mix something or do some nonsense
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Hello,
I bouth a TPA3116D2 XH-M548 Bluetooth 4.0 Dual Channel 120W amplifier.
It has a very loud anoying noise. If I turn the volumen down with the button it gets better but still noisy.
My question is, is there any fix yet? Is it possible to change the default volumen on start up to something lower that i dont have to turn the volumen always down that the noise is less.
To read 1080 pages its a lil bit too much for me. Hope some one can help.
Thanks !
I bouth a TPA3116D2 XH-M548 Bluetooth 4.0 Dual Channel 120W amplifier.
It has a very loud anoying noise. If I turn the volumen down with the button it gets better but still noisy.
My question is, is there any fix yet? Is it possible to change the default volumen on start up to something lower that i dont have to turn the volumen always down that the noise is less.
To read 1080 pages its a lil bit too much for me. Hope some one can help.
Thanks !
I do not have that board and cannot give you a solution right away, so could you please:
Describe the noise ("hiss", "humm", single tone, "buzz")?
Tell what power supply you use (and supply voltage)?
Are the "+" and "-" buttons the volume regulation?
The noise is there both when you play music and the music is stopped?
You do not have an AUX input on this board?
Tell how experienced you are with a soldering iron and do you have any spare components at home (resistors, capacitors)?
M548 Zwei kanal 2x120 Watt TPA3116D2 Bluetooth 4,0 digital audio hifi verstarkerplatine C3 005 in M548 Zwei kanal 2x120 Watt TPA3116D2 Bluetooth 4,0 digital audio hifi verstarkerplatine C3-005 aus Verstarker auf AliExpress.com | Alibaba Group
The Noise is like sough. Yes the + and - are for volumen up and down and short press for next or previous song.
The Noise is there even if it dont play music but this board set the volume to mute if no audio is playing via bluetooth.
Yes there is no AUX input. Only Bluetooth!
I tired it with a 24V 2.5A Laptop supply, also with 19V 4A, 13,3V 20A and 14,4V.
Thanks
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Sough noise must be what we often call "hiss". TPA3116 is well known for producing hiss. The hiss can be helped by reducing the gain (difficult for this board where the heatsink seems to be glued to the chip) or reducing the input impedance.
The input impedance can be reduced by connecting 2K2 resistors from the signal lines and to ground for the two signal lines coming from the pre-amplifier. You have a square marked with "L", "GND" and "R", near the heatsink and at the level of the power connector. Can you try to connect 2K2 resistors from "L" to "GND" and from "R" to "GND". Does that help on the noise?
Thank you @FauxFrench I will try it!
Thanks @dzwer I did this here https://www.diyaudio.com/forums/cla...5-bluetooth-4-0-noise-fix-13.html#post5242647
and reduce the gain from 32dB to 20dB with the removing R28 and there is much less hiss but still hiss. I think I will kept it so.
Thank you
Thanks @dzwer I did this here https://www.diyaudio.com/forums/cla...5-bluetooth-4-0-noise-fix-13.html#post5242647
and reduce the gain from 32dB to 20dB with the removing R28 and there is much less hiss but still hiss. I think I will kept it so.
Thank you
That noise occurs due to bluetooth frequency interference with the amplifier.