Burn in question and evaluation before burn in

My example will be the Almarro A205A. Low power but
very nice sound, even stock.

The total number of hours to "settle in" will,
of course, vary with the equipment and the caps, but you get the picture.

Exactly! I completely agree. Those tubes and that coupling capacitor on the
Almarro will almost certainly yield audible changes with a re-cap or burn-in - I
can see that simply from a circuit diagram. This is exactly the kind of design
that I was referring too - one that will indeed change audibly pretty much over
its entire useful life - although there should be a period of 1000 hours or so
where it is fairly stable.

Shadorne,

I'm glad we agree. :-)

I think the question then becomes, is it even possible to build an amp that is unaffected by component burn-in? My experience, and not just with the Almarro, leads me to believe that it's difficult, maybe impossible. Do you own such a piece, or have an example you know of? Do you think such pieces inherently sound better than ones that experience burn-in, or do they just drive you less crazy because they don't change?

David

The discussion is veering towards the absurd. Are people seriously arguing that they can accurately compare the changes in the sound of high quality systems when separated by hundreds of hours of actual listening time? It can't be done. Memory is not that reliable. If a component takes 400 hours to fully settle in, that translates to 2 or 3 calendar months (assuming 3 or 4 hours/day of listening). There are too many variables involved for any reliable comparative conclusions to be drawn over such a time span.

Onhwy61...yup!

There are too many variables involved for any reliable comparative conclusions to be drawn over such a time span.

I agree, unless the differences in the particular case are very great, AND extreme care is taken to rule out extraneous variables. A few possible extraneous variables which come to mind include the following; there are undoubtedly many others as well:

Ongoing aging or burn-in of OTHER system components; seasonally-related temperature changes in the room affecting component performance; changes (also possibly seasonally-related) in line voltage, or in noise levels on the ac line; if records are used, subtle wear in record grooves due to repeated playings; and last but certainly not least, improved perception by the listener of subtle details in the music, due to repeated listening.

Regards,
-- Al