A Stellar M1200 power amplifier sounds different when placed upside down.
Now that's a rather silly statement, right?
Not so fast.
Consider for a moment the difference in sound quality when listening to a stone cold M1200 vs. one that's been on for an hour or so.
Clear differences can be heard.
One thing to consider is operating temperature. The M1200s (like all amplifiers) have a nice and comfortable operating temperature range: too cold and it's performance is altered. Too hot and we get a different result.
Place the M1200 upside down and the temperature of the internal modules changes because they were mounted with the expectation of the amplifier being upright.
Is this a big deal? Heavens no. The M1200 will sound great either way.
The point is it's best not to immediately reject what at first seems like an absurd claim.
Roll it around in your head for a while. Sometimes there's actually a bit of science behind it.