After Burn-in...........?

[joestcyr]

Question; after a full recap (in my case au20k) lets say I’ve set bias and came out very close to spec. In a perfect world, it sounds fantastic.
Then I do a standard(?) burn-in,
Does burn-in Alter bias? To the point it requires adjustments? ?I await wisdom of the AK prophets

 

[_mano]

I've set the bias on initial burn-in and take a note of it. Let it burn-in and warm up so its at the correct operating environment and then check the bias. The drift should be tiny if any and can be biased to be spot on..
Let it cool down fully, check bias levels when cold and when at operating temperature (with covers/lids on etc..) to make sure built in compensation is working as per design.

If you do find that the variation is huge, then there will some components that may need to be investigated as to the drift.

 

[tnsilver]

Does burn-in Alter bias?

The concept of capacitor burn-in is controversial and I hold the opinion it does not exist with main stream mfgr's. The official literature is vague - to say the least. What alters bias is temperature over time - so unless you've brought the amp back to ambient temperature between measurements and measured time elapsed - I wouldn't pin the difference on burn-in, which I wouldn't do anyway.