[Jost2017]

Hello.
New member here. I recently bought a NuPrime STA-9 amplifier on the used marked, and have been happy so far, but today I noticed that there is no sound from the left channel. I've checked that the problem is not with the speaker (it works through a different amp).
The right channel works fine, but the left is dead silent no matter if  I use balanced or unbalanced cables or how the switches on the back are set.
I've opened it up but cannot locate any loose cables etc.
I'm unsure if the problem is with the input or the output.....

Have anyone had a similar problem? Any fix? Tips?

[Jost2017]

NuPrime STA-9 the title should read...

[Jost2017]

NuPrime STA-9 

[srb]

NuPrime STA-9

You can edit the Subject Title field of the initial post. 

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[Jost2017]

Thanx! I couldn't find the edit option at first......

[Phil A]

Welcome - sorry to hear about the issue

[Jost2017]

Thank you. Well it's strange because it's been working flawlessly until today. I'm a little careful about cutting / modifying inside, but there is a black rubber / tape with"TUBE" written on it connecting/linking the red and white cables going to the output channel. Can a faulty / broken tube be the issue? (I cannot see if the tube is broken without removing the rubber cover...)

[timind]

Here's the inside pic. Looks like some sort of network inside that shrink tube. Hopefully someone from Nuprime will chime in here.
I don't know your technical skill level, but if it were mine I'd unplug those red and white wires and swap them to see if the problem moves. Of course with the amp off.

[Jost2017]

I know how to solder/unsolder etc, but I can't find a way to remove the cables from the white plastic connector on the board (I don't know the term) without using force. Do you just pull them out or is there a hidden trick / switch to make them let go?

[timind]

I know how to solder/unsolder etc, but I can't find a way to remove the cables from the white plastic connector on the board (I don't know the term) without using force. Do you just pull them out or is there a hidden trick / switch to make them let go?

It looks like those plugs have clips on them. You should be able to squeeze the plug to release the clip and pull up.

Have you contacted Nuprime? That would be better than taking advice from some guy on the internet.

[Jost2017]

I've contacted nuprime, waiting for their reply. I just thought I'd also check online if someone had experienced the same problem and had a suggestion..