Schiit Asgard Modification
No, this isn't a mod to make it sound better - it already sounds pretty good. This mod might save your life.
A friend of mine claimed that his Schiit Asgard blew up when he turned his power conditioner on. He sent the Asgard to me to check and repair and so I did.
The story was that his Asgard was always on even when the power switch was off. I had a look once and powered it up all by itself and it was working fine. He took it home then plugged it into his power conditioner and it blew. A bright white flash was seen through the vents and tripped the house breaker. Afterwards, the Asgard no longer works.
When I got hold of the unit, before opening it, smelled the top vent to have a guess as to what had burned and there was no familiar scent of burnt semiconductors or FR4.
After I opened it up, this was what I found.
Fuse was blown and there is a huge carbon soot around one of the fuse clips
Upon removing the fuse clips, the cause of the problem was apparent. A ground plane runs around all over the mains parts with around 1mm of clearance. Safety rules for power supplies dictate that there should be at least 4mm or more of clearance (it is not uncommon to see 7mm or more in properly designed products) between the primary and secondary for safety against high voltage spikes (see those Hi-pot stickers in SMPS's - high potential testing applies a few kV across the primary and secondary and no arcing should occur.
Ground plane runs under the metal fuse clips.
The thin soldermask must have been damaged - which could have
explained why the unit stays on even with the switch at off position.
Applying 120V (live - earth) across the short blew it apart.
A portion of the fuse clip also blew apart.
There is only 1mm clearance from the live mains connections and the ground plane!!!
The fix - after cleaning the soot with IPA and cotton swabs,
Two layers of kapton tape to insulate the metal fuse clips
from the ground plane underneath.
Poke holes where the pins go through and solder the clips back.
After thinking about all this, I feel that me and my friend are lucky not to be electrocuted and be still alive today as he has been using it a few times when he mentioned it started happening (unit staying ON) and while I was holding the unit while testing not knowing the danger I was in.
Although the amp works now, I would not recommend using it unless plugged to a three prong grounded outlet to ensure that the metal chassis is earthed for maximum safety. You wouldn't want 120V running through your brain when you're listening, that isn't the "electrifying" experience you were hoping for when listening to your music. I may have to take a look at my Bifrost for similar safety design flaws when I get it back.(loaned it to a friend) and maybe a Mjolnir and Gungnir - I know someone who has those and hopefully he would let me have a peek inside.
All said, this is not to detract others from buying this unit, just a heads up on the safety aspect of the design. It sounds good and has a lot of satisfied customers and a quick search in google didn't turn up similar incidents so it may be rare but does not mean it won't happen to you.
Page created and copyright R.Quan © 23 Feb 2013.