Are separate outputs really separate on SMPS?

[madmarcus]

As mentioned in my thread on a workshop bluetooth amp project I have a random SMPS that I am considering for use in an amp. No it's not ideal or normal for a tube amp even if it is marketed as such. But I have it already due to another project that needed 48V with more current (that project is on hold).

Aliexpress SMPS

It's configured with three outputs

Output voltage: +48V GNG -48V / current: 2.6A
Output voltage: +15V GNG -15V / current: 1A
Output voltage: DC12V / current: 1A

Given that I can deal with only 1A of current is there anything I should worry about before stacking the +-48V and the +-15V to get a B+ of 126V?

Working with robots hasn't given me much experience with SMPS. The power supply was in my parts drawer but I'd still hate to blow it up with a dumb move based on expecting all three segments to act independently of each other.

 

[mastodon]

Usually all grounds are connected, so the outputs cannot be stacked.

 

[astouffer]

Agreed.

 

[Depanatoru]

The windings have a central tap ( 2 diodes rectification ) and are already stacked 😀... 48V has only extra turns on top of 15V voltage and so on .
Like in a computer power supply where the 12V voltage is using the 5V windings + extra turns .

 

[madmarcus]

Thanks all. I figured that was probably the case but some random post-Christmas thoughts came into my head.

 

[hbc]

Usually all grounds are connected, so the outputs cannot be stacked.

Indeed, but have you actually checked with an ohm meter?

 

[madmarcus]

I'll check later once the holiday stuff is over and I have hobby stuff back out. I don't really expect anyone to know for certain without access to the specific power supply in question.