Yamaha EMX660

[kmiller1610]

Suggested repair steps?

- One of the amps has excessive noise

- The other cut out repeatedly (microphones and CD) during peak performance scenario (two singers belting, music up loud). Once the action got back to normal, everything worked fine...

Thanks for any help you can offer....

[Enzo]

Test the parts separately. Plug something into the power amp in jack, that will disconnect the mixer circuits. Still noisy? Can the noise be controlled by the master fader? How about the graphics?

And the channel cutting out? First swap speaker cords. Once you have eliminated the cords as the problem, then swap the cabs. We need to make sure it isn;t the speakers cutting out insteaqd of hte amp.

Let's say the left channel and speaker is cutting out. Use a couple patch cords to reconfigure the powr amps so the left amp drives the right channel and vice versa. I want the left channel signal driving the left speaker, I just want the right power amp to do it. If it is the amp itself, then the other side should start cutting out. if the left still cuts out using hte other amp, then it isn;t the amp.

it is possible the power amp is tripping into protect. We'd have to explore the circuits if that is the case.

Anf if your amps are doping monitors and mains instead of left and right, the test still apply, just adapt.

[kmiller1610]

Thanks for the help. I just made a $21 donation as a thank you. I wasn't sure I'd get a reply, so thank you.

I think the idea of the amp tripping into protect makes the most sense.

I am running a total of 6 mikes into the system (5 wireless). I am using two powered speakers, so I'm mainly using the amp as a mixer. The volume settings are very low, both on the amp and only moderate on the speakers themselves.

I did not have any problems with the cut -outs until late in the show with two singers singing at the top of their lungs. Both the music track and the mikes themselves cut out at the same time. Then they came back a few seconds later.

This would seem to suggest the protect mode you mentioned. I will do some testing as soon as I get the time and see if I can duplicate any of this....

[Enzo]

The protect circuit protects the power amps. if you are only using the mixer portion, that wouldn;t seem to apply.

[kmiller1610]

The protect circuit protects the power amps. if you are only using the mixer portion, that wouldn't seem to apply.

Boy.. you're good. After spending 2 hours with the jamokes from guitar amp who sold me the hardware, I found out I was plugging into the power amps and the speakers were cutting out from being overloaded.

When I bought the amp, it came with two regular speakers. When I upgraded to two very nice powered speakers (Yamaha MSR-400s), the moron told me to just plug em in as I had before.

So there is nothing wrong with the amp at all. Boy does it sound better running off the line output! Fortunately for me, I had always run the amps at low levels until Sat night when the strangeness began.

Please forgive me for wasting your time. But I think registering here got me juiced up to get to the bottom of this.

I'll be back if I have any more issues.