Hi, I have a little problem which is non-diy related but since you guys know these things this seemed lika a good place to ask.
The thing is that i bought an Amplifier from China and had it delivered to me in sweden. When i got everything wired up i noticed a kind of thumping in the loudspeakers....Totally random and it sounds like somone taps a finger on an Acoustic guitar. It doesn't need to be a source (cd etc.) connected. The only manipulations made are the switching of the powercords plug. Theres the same eletricspecs in sweden and China.
Does anyone have an idéa of what it can be and what can be done about it?
The thing is that i bought an Amplifier from China and had it delivered to me in sweden. When i got everything wired up i noticed a kind of thumping in the loudspeakers....Totally random and it sounds like somone taps a finger on an Acoustic guitar. It doesn't need to be a source (cd etc.) connected. The only manipulations made are the switching of the powercords plug. Theres the same eletricspecs in sweden and China.
Does anyone have an idéa of what it can be and what can be done about it?
No tubeamp, rather this one:
Xindak A100
it's not like motorboating just lika a random thumping...somtimes its not present just to appera minutes later. Tryed to chande powercord by the way...didn't help.
Xindak A100
it's not like motorboating just lika a random thumping...somtimes its not present just to appera minutes later. Tryed to chande powercord by the way...didn't help.
If the "taps" comes randomly, I wouldn't suspect the power supply.... 
Random taps and noises are most common with bad solderings or connections.....
If you do not want to send it all the way back to China, you may consider to "lifting the hat" of your new amp, and apply some cooling/freezing spay to try to find the bad spot......
Random taps and noises are most common with bad solderings or connections.....
If you do not want to send it all the way back to China, you may consider to "lifting the hat" of your new amp, and apply some cooling/freezing spay to try to find the bad spot......
You are closing in
When the "taps" are more presant when amp is cold, it's seems even more likely that the problem are caused by bad soldering...
When using cooling spray on a wormed up amp, you cool down a specific small part of the PCB (or other connection) at a time... If the "taps" then starts again, you have hit the right spot....
When the "taps" are more presant when amp is cold, it's seems even more likely that the problem are caused by bad soldering...
When using cooling spray on a wormed up amp, you cool down a specific small part of the PCB (or other connection) at a time... If the "taps" then starts again, you have hit the right spot....
eh...no, im working up the nervs to use my rather rundown solderingiron on a PCB with insanly small spaces
I don't know if there are solderingpoints on the other side and i didn't remove the different PCB's. I did however check to see if the resistors sat firmlly in place (which they did). But i think that i will wait just a while untill it starts to really annoy me and then start to do something about it.
I did find out something new thou, it does NOT need to be cold to sound strange. So heat has nothing to do with it. I thought that it could be due to "unclean" elecricity since i live in an appartment building but that usually manifests itself as a backgroundnoise, right? Anyway, that should not be confined to just the left channel.
I think i will have to have someone look at it to find the fault im sorry to say.
another thing, what is the main reason for backgrund noise in an amp? if i now need to have help perhaps they can do some cleaning up of that too? here's a picure of the thing btw
and the red arrow indicats the bad solderpiont
I don't know if there are solderingpoints on the other side and i didn't remove the different PCB's. I did however check to see if the resistors sat firmlly in place (which they did). But i think that i will wait just a while untill it starts to really annoy me and then start to do something about it.
I did find out something new thou, it does NOT need to be cold to sound strange. So heat has nothing to do with it. I thought that it could be due to "unclean" elecricity since i live in an appartment building but that usually manifests itself as a backgroundnoise, right? Anyway, that should not be confined to just the left channel.
I think i will have to have someone look at it to find the fault im sorry to say.
another thing, what is the main reason for backgrund noise in an amp? if i now need to have help perhaps they can do some cleaning up of that too? here's a picure of the thing btw
and the red arrow indicats the bad solderpiont
Attachments
Ok lets take it easy here
If you not feel saf using a soldering iron, then don't...
You can mess things up 10 times worse than they where
Just for your information: The PCB in your amp is doubble-sided, meaning that the solder point goes through the PCB. A re-soldering on one side of the PCB would also repair a bad soldering on the other side.....
Cold or hot.... Using cooling spray (-30C) would reviel almost any bad soldering or component. Try it! It's cheap
It could be that your amp is extreme sensitive to noise on main power lines caused by eg. electric heaters turning on and off etc.
however it has bee n many years since I last heard of that here in Scandinavia....... Have you tried the amp at a friends place ??
If you not feel saf using a soldering iron, then don't...
You can mess things up 10 times worse than they where
Just for your information: The PCB in your amp is doubble-sided, meaning that the solder point goes through the PCB. A re-soldering on one side of the PCB would also repair a bad soldering on the other side.....
Cold or hot.... Using cooling spray (-30C) would reviel almost any bad soldering or component. Try it! It's cheap
It could be that your amp is extreme sensitive to noise on main power lines caused by eg. electric heaters turning on and off etc.
however it has bee n many years since I last heard of that here in Scandinavia....... Have you tried the amp at a friends place ??
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