burning in

[Professor smith]

I would like to ask Nelson if ''burning in'' components is a well defined concept?

I have read in hifi magazines and heard that burning in is supposed to improve the sound. What basis is there for this idea?

 

[Nelson Pass]

I will only address burn in from the standpoint of an electronics
manufacturer, which is the thing I know with some authority.

We burn products in for two reasons -

1. We want to see if anything fails.

2. We want to readjust the amplifier against any drift in performance
that comes with a burn-in.

Some amplifiers depend on delicate balances between components to
achieve best performance, and are tweaked to a "sweet spot". Something
like a First Watt F5 or an F3 is a fine example of an amp which appreciates
being tweaked back into the sweet spot after burn-in. The difference might
be reasonably subtle - distortion drifting over the range of .002% to .01%,
or bias drifting a few percent.

Some, like an F4, don't depend on the subtle interactions of components,
and rarely appreciate re-adjustment after burn-in.

 

[Manu]

Some, like an F4, don't depend on the subtle interactions of components,
and rarely appreciate re-adjustment after burn-in.