Yamaha PC4002M

This is a question for those who have this amp:
If you put your hand on its cover when it has been running for some time, is it hotter on the left side?

Mine does this. I don't know for how long it did, or even if it always did, I just noticed recently. The difference in temperature is substential.

That seems odd since this amp is symetrical in its layout:

http://www.audioheritage.org/vbullet...1&d=1200757032

the only difference comes from the black cables attached to the front left.

So fellow PC4002 owners, what is your experience?

Nice Amp!

No personal experience but perhaps some general observations.

Have you checked DC offset and bias on each channel? If you have too much bias, you'll run more Class A than normal.

Also, should we assume you have good ventilation for both sides' heatsinks?

Also, since your amp is fan cooled, best to check both fans (probably take them out and clean them, then check for smooth and similar operation fan speed. Also, clean out the filters in the front / back if there are any, and blow out or wipe off any internal and external heatsinks and move any wiring that could impede airflow. Dust is a very good heat insulator so you want to have a clean amp / heatsinks.

If all those measure do not show any problems, then you need to check the amp for proper bias operation.

I mech986,

I remember that you also have some yamaha pro amp, right? (PC2002? I also have one of these, the best of the serie in my opinion)

The bias has been set by technicien maybe one year ago. I will check with him.
Concerning a DC current in the input, the source is a behringer DCX2496, I will check this also. The amp is supposed to enter protection mode if the DC exceeds +-2V.
The heatsink do not have many room on their side, but it is the same on both sides, and the fans only start at 60°C, so I think it is not a heat dissipation problem.

thanks for your advices!

http://www2.yamaha.co.jp/manual/pdf/...mp/PC4002E.pdf