question for SLP05 owners:

You might want to call and ask Cary Audio directly what has been learned since the publishing of the last operating manual version. Ask the warranty-repair decision maker person there these days - and not a general sales person. I've had to deal with other components where the operators manuals needed clarification, updating.

What does #8 really mean below and is "stacking" acceptable or not.   

SLP-05 Cary Owners Manual, Page 2, reads: 

7. HEAT: Position the unit away from heat sources such as radiators, heat registers, stoves, or other units (including amplifiers) that produce heat.

8. VENTILATION: Slots and openings in the cabinet create ventilation to protect the component from overheating. These openings on the top and bottom panels must remain unobstructed. Allow at least 6 inches (16cm) of clearance above the unit and an opening behind the unit for airflow. Do not place the unit on a bed, sofa, rug, built-in bookcase, or rack without adequate ventilation.

https://www.caryaudio.com/wp-content/uploads/2021/01/SLP-05_manual.pdf

If it were me and you see any type of ventilation holes under each of your units, maybe consider ways of ensuring sufficient air gets in.

Yes, we’ve both seen photos SLP-05/Power supply stacked, and I just checked a few reviewers that had them on display not stacked closer together. Maybe you can gap them some if you must stack. Same as some rack mount computer blade systems in racks within big Colo data center facilities. Moving Air is your friend if you want equipment to last.

If you do decide to stack, maybe you could do something like this for each, some kind of risers underneath each one, then stack, sort of like this. Can’t find a good photo but you get the idea. Stuff inside these units melts ages, cracks, over time from heat, this we know.

No worries @immatthewj I was typing this as I rotated my tube monoblock amps out, inserting and warming up my other Class A 50w solid state amp on/off past few days.  That SS class A gets to about 45-47C on the heat sinks as biased, and ensuring I have nothing above it or near it. Above it sits my Cary SLP-98L preamp, I keep the power supply away and sufficient air above it to breath in a similar manner. I use to stack some other dual mono HT SS amps I had years ago, not any more. Burned out one of them on the top of the stack, learned a lesson.   

As for heat, you might compare with others with SLP-05s and see if anyone has used a Infrared Thermometer Laser Temperature Gun and checked temps at all across different surfaces, tubes, etc.  

Are you running a different set of tubes, rectifiers, in it now then compared to the past and do you suspect more heat after trying different tubes - or anything like that?   

 

@lwin They were made to be stacked . I recently sold mine to a buddy who has them stacked just like I did for years.

@harpo75 The reason Cary Audio changed the plate on top of the power supply to one without “foot indentions”, was to discourage people from stacking ...

And yet another photo of the indentions, and not stacking. If the indentions on the power supply top plate were removed - there is a reason for it as @harpo75 suggested. Worth doing more research on this topic, sometimes designs change for a reason. I bet the warranty decision maker at Cary Audio can share updates on what’s important to make the gear last longer. They see the incoming repairs.