bias amp while hot or cold?

[nicksmurf]

Should I bias my amp while it is cold, or after it warms up to normal operating temp? Since I guess the bias current seems to rise with the temperature. Whatever I do I'm replacing the pots first.

- Nick

 

[jam]

After half an hour to an hour.

 

[nicksmurf]

Thanks, i wasn't sure.

 

[sam9]

Some recomend connecting an input signal and a load (speaker or dummy) and running ithat way until the temperature stabilizes. Then disconect the signal and load and set the bias before it cools.

 

[hugobross]

After having set up the bias check again after a while!

Repeat this several times.

 

[peranders]

Good idea to really make the amp hot, either by turning up bias (if it's possible) or by high output power. When it's really hot, adjust the bias. Then in cooling process, measure the bias at a few temperatures so you see that it's rather stable or the bias increases slightly with lower temperature. If this is the case the amp will be 100% regarding to bias. It's important that all parts inside have reach stable temperature and this can take 15-30 minutes at least if you include transformers and all big parts.