Stereo amp behaving in mixed-mono. how to separate?

[iansoh]

I recently bought a cheap power amplifier (Yulong T-amp, made in China).

Problem:
Stereo signal keeps getting mixed into mono.

When I pan hard left or right on my mixer, the left or right signal respectively comes out thru both speakers at equal volume.

When pan centre, both L and R signals are played through both speakers at same volume.

What is going on and how to rectify this problem?

 

[THOA]

I am having a similar problem with sounds coming in both speakers as mixed. But mine is not a cheap amp problem. More like a cheap stereo to mono splitter adapter problem.

 

[blueprintstudios]

iansoh :
"When I pan hard left or right on my mixer, the left or right signal respectively comes out thru both speakers at equal volume." = thats a good thing right? as in thats what it was meant to sound like.

"When pan centre, both L and R signals are played through both speakers at same volume." = becomes "mono" "centered" ?

well if i'm not wrong la

stereo signal (2 mono) > mixer channels #1 and #2 > speakers

@ the mixerchannels #1 and #2 part. naturally they exist as [seperated mono channels] in a "stereo" signal. so it SHOULD sound right if you pan it L100 and R100 all the way. if you leave it complete 0. you're actually combining the (stereo) 2 mono channels into 1 single mono sound. which gives that "mixed mono" sound.

i'm not too sure myself, i only had this "related" problem when I first recorded drums > mics > analog mixer > 1/4jack out into my korg recorder. then I had to pan it "L100 / R100" to have it stereo.

THOA : "More like a cheap stereo to mono splitter adapter problem."
i'm assuming stereo signal > Y cable 1/4jack Stereo to 2x 1/4jack mono ?

did you check whether the "1/4jack stereo end" is 2 black striped ?

 

[soft]

Hi Ian

What mixer are you using? Some troubleshooting you can try to narrow down what is causing this.

1. Connect a CD player directly to the amp (if this is possible). Listen if the stereo seperation is working.

If the above is working fine, then

2. Connect a microphone to your mixer. Put the channel's pan to Center. Adjust gain and level. Test if your voice is coming through.

If yes, then

3. If your mixer Master has L-R level, pull down the LEFT level.

Is there sound coming from your left speaker? If yes,

4. Pull down the Right level.

Is there sound coming from your right speaker?

If the above experiment does not yield results, try to connect 1 cable from source to amp at one time. Example, mixer Left OUTPUT to amp LEFT INPUT. Is sound coming only from LEFT speaker. Then disconnect LEFT cable and do the above for the RIGHT signal.

* Remember to lower amp level when connecting/disconnecting



blueprintstudio also mentioned about the hookup of your instrument to mixer. Keyboard LEFT/RIGHT output to mixer channel 1/2. 1 should be hard pan 100% left and 2 should be hard pan 100% right.

 

[unsane]

might be an internal short in the input/output section of the amp..open it up and check the wiring perhaps?

 

[iansoh]

Hi all, thanks for the response. i took a gamble and found out that the binding posts were soldered to the wrong terminal on the circuit board. couldn't open up the amp chassis to check, so just simply swap the negative terminals around and voila, everything works properly now.

i got the idea from the fact that for some amps it is possible to bridge the terminals to connect a subwoofer to receive both L and R, which gave me an idea..

so much for cheap amps. haha.. the chinese factory worker must have been sleeping or drunk when he soldered my unit!

 

[blueprintstudios]

i dont' get it but i'm glad it all works out now.

 

[parablue74]

Seems like your power amp has a serious crosstalk issue.

 

[THOA]

THOA : "More like a cheap stereo to mono splitter adapter problem."
i'm assuming stereo signal > Y cable 1/4jack Stereo to 2x 1/4jack mono ?

did you check whether the "1/4jack stereo end" is 2 black striped ?

Your assumption is half right. Problem is that the "stereo" jack of the Y cable ( wouldn't even call it a cable, it's really short) is female. So I can't be too sure if it is even stereo. There is no indication on the label of teh package to confirm it. There is a chance of it being mono, which very odd connection set up in my opinion. :?

 

[blueprintstudios]

take photo of it and put it up on imageshack.us for us to see??

hahah BZZZZ DONT USE THE QUOTE BUTTON!

 

[THOA]

hahaha, but i trimmed down to what is necessary, and your post is like a few posts higher than this .

will try to post pics when i can.