Can anyone decode this?

Hi,

My amps have been overheating (RB993). I have been told by the Rotel service team that the bias is set to high.

What is the Bias?
What happens if i set it to low?

The Amp is a Class AB. The amp will overheat quicker if on idle than if playing music! Is there anyway of disabling on of the channels?

 

look up bias an amp on TNT

http://www.tnt-audio.com/clinica/bias_e.html

I think that should help explain things !

 

Bias is simply current through the output transistors and the reason for this is to avoid or at least reduce crossover distortion which sounds pretty nasty. The disadvantage to turn up the bias is a wamrer amp and higher power consumtion and less headroom becasue of hot heatsinks.

It may be sensistive how you set the bias because if you haven't got the full control over it you may end up with unstability and oscillations. So sometimes you may need oscillscope and signal generator in order to judge wether the trimming was good or not.

 

Thanks for the help, Bias overheating problem fixed.
3 channel amp converted toa two channel by pulling a few fuses, asthe amp is A in idle it caused major heat!

Case removed and fans fitted =-)

No more overheating without messing with the complicated bias!