Stax SRM323s hum on right channel.
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wind016

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I'm noticing a pretty loud hum on the right channel of my amplifier. The hum is still there after if the source is off. What should I do? I'm trying to use the grounding terminal but not quite sure where to connect it. It's strange that the hum is only on the right channel and pretty much silent on the left.
 
 
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wind016

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I just also noticed that when music is playing through the source, the music could be heard through the right channel even though the volume is completely all the way down on the amp. It is like the music is leaking through into the right channel which is also where the hum occurs.
 
Scratch that. No music is leaking when it's on zero. I only didn't move the right balance knob all the way. There is still hum on the right channel though.
 

 
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spritzer

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Hum in the right channel only points to a grounding issue.  Check all connections inside the amp from the RCA inputs through the pot and to the PCB.  Also swap the input cables and see what happens. 
 
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wind016

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Quote:
Hum in the right channel only points to a grounding issue.  Check all connections inside the amp from the RCA inputs through the pot and to the PCB.  Also swap the input cables and see what happens. 


Thank you for pointing that out! Now I know I probably do not need to replace anything, but I'm just a bit lost at where to start. I'm no electrical engineer. Well, here goes nothing...
 
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wind016

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I tried taking apart the whole thing and couldn't find any loose connections or solder. Everything seems clean so I'm not sure what the problem is. I was considering disconnecting the volume pot and wiring straight to the PCB, but I found these threads that didn't end so well:
 
http://www.head-fi.org/t/159022/disabling-volume-control-on-a-stax-energiser
 
http://www.head-fi.org/t/159824/help-fixing-my-stax-energiser-please
 
Anybody have some ideas? Anything would be appreciated.
 
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actually ES dual stator balanced drive can be confusing - I've heard loud hum in one side which turned out that one stator driver circuit was totally broken, input device dead, feedback loop open, but you could also hear music since the other stator driver on that side was still OK
 
I had serious test equipment - including 3kV rated 100x probe for my scope - not sure what a lessor equipped hobbyist can do
 
 
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wind016

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Quote:
actually ES dual stator balanced drive can be confusing - I've heard loud hum in one side which turned out that one stator driver circuit was totally broken, input device dead, feedback loop open, but you could also hear music since the other stator driver on that side was still OK
 
I had serious test equipment - including 3kV rated 100x probe for my scope - not sure what a lessor equipped hobbyist can do
 

I only have a screw driver and soldering iron... =/
 
How is the Stax service in the States?
 
 
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Is there any loose connection at the pot (the blue thingey)?
 
This thread is probably more suitable for the DIY section.
 
 
 
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wind016

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Quote:
Is there any loose connection at the pot (the blue thingey)?
 
This thread is probably more suitable for the DIY section.
 
 


No, there isn't anything loose at all. All the wires are through the holes and soldered on. I'm starting to think that maybe one circuit really is broken.
 
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How about the brightness of LED's, are all six the same?
 
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One LED is dimmer than the rest and I think it may be connected to the right driver circuit. I have no clue what to do there though...
 
I circled the LED with a yellow circle.
 


 
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Just to make sure, this is a hum and not a hiss right? 
 
And since you didn't mention it in your posts, have you tried plugging it to another AC outlet and/or with another power cable? 
 
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Quote:
Just to make sure, this is a hum and not a hiss right? 
 
And since you didn't mention it in your posts, have you tried plugging it to another AC outlet and/or with another power cable? 

Yes, I tried plugging them through outlets throughout my home and with my DAC's power cord. It still has the hum..
 
 
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If you disconnect both RCAs from your source and the volume control is all the way down, is the hum still there?
Again with the source disconnected and you turn up the volume knob, does the hum get louder?
If your AC plug has a ground and you use a cheater plug to not connect the ground pin, is the hum still there?
 
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