Not everything, I found some parts (pot meter extension shafts for example) that cost half on Conrad of what they cost on tme.eu
I have just powered up mine 1.64$ modules, and they sound fine with signal. But if I pause the musik on my phone, I get loud noise. Also if I have no cables in input, I get loud noise. Why?
I power them with two lenovo 90 watt 20 volt PSU's
I power them with two lenovo 90 watt 20 volt PSU's
High impedance on the inputs will pick up noise.
When you pause your phone it probably went into high impedance by disconnecting the output...mine does.
When you pause your phone it probably went into high impedance by disconnecting the output...mine does.
I find I only get loud thumps/pops on power up if the input isn't initialised.
i.e. My Pi plus soundcard needs to be up and initialised before I switch the amps/speakers on.
I'd theorise that something along the way is powering down its audio circuits on mute, then powering up on resume.... Or similar.
You need something to constantly feed reassurance to the amps. 🙂
Your phone can drive ~32 ohm earbuds?
So load the phone with 50R and see what happens.
I'm not sure, what you are trying to say. It's not my phone that's having an issue. It's the amplifier modules. It doesn't matter if its my laptop or phone, and also if there is no cable it will make the noise (full output). Do I need a buffer, or something else?
I use some form of low impedance drive on my amps...no noise.
Open circuit...noise.
Do you have a pair of ~50R resistors you could try?
yes - probably somewhere. But, why didn't "they" just install it on the board? I have never experienced this before.
Should I just connect a resistor from signal to signal gnd? And, does it have any negative impact on sound?
Should I just connect a resistor from signal to signal gnd? And, does it have any negative impact on sound?
The 50R is just for use with your phone.
Try higher values if used with another type of source.
You may have read (somewhere on here) that some pots have more noise at mid settings...because (IMHO) the impedance is lower at each end of the pot and allows more noise pickup in the higher impedance mid position.
Experiment.
You will have to tell us if there is any negative impact on the sound.
I did not misunderstand.
The 50R is not to make your phone happy.
It is a value to be used with your phone to reduce the noise:
Have you tried it yet?
But I am not going to use my phone, so I need a solution that works no matter what source I use. And since I don't experience this with any other amplifier I own, something must be missing on this amplifier module. Perhaps it's not intended to be used with a signal directly on the board, but intended to be used with some kind og preamplifier.
As I said...I use a low impedance source.
Usually an LME49710 (or LME49720) and drive the amplifier with a balanced (differential) source.
I have not tried any tube based preamp so I cannot comment on those.
If the preamps you are using (or are going to use) has a low output impedance then it should work fine.
Some pix of my build.
Usually an LME49710 (or LME49720) and drive the amplifier with a balanced (differential) source.
I have not tried any tube based preamp so I cannot comment on those.
If the preamps you are using (or are going to use) has a low output impedance then it should work fine.
Some pix of my build.
Attachments
Whoa... DUG. You built a mechanical gear drive to turn two pots with one knob?!? That is the height of cool. 😀
Ya, pot stays at about 50% so I don't need to worry about exact tracking at the low end.
Actually use the Laptop (video player) volume control.
Picked up a couple of Sanwu TPA3118D2-boards, or well, copies of the boards it seems. All the components have different names even though the layout is basically the same as the original Sanwu board. On my boards you have to remove R6 in order to lower the gain to 20dB. I removed R6 (R27 for all of you with different boards) before even hooking the boards up to test them out.
I have to say that they sound pretty decent, especially since they're only about 2€/piece. One thing I noticed is that the background hiss differs greatly from different SMPSs. I assume this is the case for all of you?
My FSP-120 AAC is unfortunately the worst offender of them all, but some random no-name brand 15V 3A SMPS provides the least background hiss.
Can anyone recommend any mods to the boards? Maybe replacing the filter capacitors with low ESR caps?
I have to say that they sound pretty decent, especially since they're only about 2€/piece. One thing I noticed is that the background hiss differs greatly from different SMPSs. I assume this is the case for all of you?
My FSP-120 AAC is unfortunately the worst offender of them all, but some random no-name brand 15V 3A SMPS provides the least background hiss.
Can anyone recommend any mods to the boards? Maybe replacing the filter capacitors with low ESR caps?
Last edited:
Just saw this cheapo amp, even available on Amazon. Can't quite tell, but does this look its actually set up as PBTL configuration?
