300B Warmup versus other tube or SS amps?


Anyone have experience in warming up their 300B SET amp?  My push pull tube amp comes on duty after about 15-20 minutes or so of warmup.  My 300B sounds distinctly better after 60-90 minutes of warmup.  If it's on for several hours it may even marginally improve from there.  It sounds a bit flat out of the gate (no warmup).  My other amps are not as sensitive to this.

I am just curious to what folks have observed in there setups.  
128x128jbhiller
Does a longer warmup time have to do with the amp being Class A?

For optimal sonics my Class A push/pull takes much longer to warm up than my AB amp.
 
 I ran (run) a Cary SLP 98P  Pre with a Cary V12R then a Cary Cad 120's and the manual calls for a 5 min warm up for the pre and 3 min warm up for the amps. Not sure on the Canary M 350's so I warm them up for 10-15 min. All the amps seem to sound better after 30 min.
@lowrider57,  Great question! Maybe someone with more tech experience than us will chime in. 
I'm sure it depends on your amp's my 300b SET seems to be fine after 10mins or so depending also on the time of day as I live in the city so supper time it sounds not great after much better.
I turn my tube gear on ten minutes before listening. Solid state you can leave on all the time.