Oh dear, what a nasty experience I had the other night.

Tried a new Linear PSU which runs at 15V 3A on my Dac last night, a
trial from a good guy on AOS.
It has a +-10% variable voltage which can be adjusted.

Anyway, hooked it up with a meter of Mark Grants mains cable and sat
back to enjoy.
Checked wiring was OK then checked again.

After a couple of minutes a strong smell of ammonia(?) coming from the
Dac and a crackling noise...
Shit!
I powered off right away, only to notice that the Dac was red hot where
the big smoothing cap was?
oh dear..

Left the case to cool and opened up the lid.
The big smoothing cap had swollen and had been "sweating" inside the case!
The PCB was covered in some kind of slick coating and it stank of
ammonia or something.

Leaving the Dac to cool, I got the multimeter out and tested the voltage
on the power supply.
Its 15v +-10% so should have been OK?
Nope - it was reading 31V!!!
How is this possible?

Something must have happened to the PSU it in transit - I have no idea what.
Adjusting the voltage +-10% screw though got it down to 15.6V...what it
should have been.

I should have double checked BEFORE I plugged it in, lesson learned!


Thinking my Dac was knackered I hooked it up hours later once the Dac
(and myself) had cooled down and knowing the supply was working as it
should at 15v+
The Dac worked but with a few problems:

1. The input selectors didn't work properly. No matter what you selected
it only played Coaxial#2.
2. The Optical input didn't work.
3. Sound quality had suffered - not anywhere near as good as before
prior to the big smoothing cap going ppffftttt.

Pretty pissed off I went to bed, thinking to look at it again in the
morning.

Everything works!
The sound quality is not what it should be but I suspect the burst
smoothing cap is the problem?
I'm guessing the Dac had overnight to "dry out" and fix itself?


SO...
from a position of "improving" my linear PSU I'm now 2 steps behind
where I was before.


What's the next move Guys...
My next mod to the Dac after improving the PSU was to replace the big
smoothing cap with a film cap, so maybe its the ideal time to look at it
- a blessing in disguise?
(I use Murata regs in my Dac, which has all the mods done and Gator
board fitted).

Should I be worried about anything else having went pop - everything
seems to work and the heat was only coming from the smoothing cap?

The Dacs unplugged till I can get this sorted.

Thanks.