[time-nuts] SMPS or conventional?

[ed breya]

Yes, the physical/thermal stress wear and tear depends on the device 
response relative to the ripple frequency. TECs aren't the only things 
with these issues - even modern high power LEDs used for illumination 
are known to last longest when run from "pure" DC, for a given average 
power level.

For our sorts of applications, the ripple issues should be moot. As has 
been mentioned, we don't want TEC drive ripple signals near precision, 
sensitive circuits either, so properly filtering and cleaning the 
applied power both reduces electrical interference, and prolongs the TEC 
life. Except for the increased complexity, who wouldn't want that?

Ed