Schiit Midguard just died and the blue smoke escaped

[Brian Hall]

I purchased the Schiit Midguard headphone amp on 2/28/24. It has been great till now. As I was unplugging my headphones, there was a popping noise and the blue smoke came out along with a burning smell. The room still smells like it.

It was the 1/4" jack since I had that cable on the HD 800 S headphones.

Has anyone had something like that happen before when just unplugging a headphone?

I submitted the request for assistance form to Schiit.

I'm glad I kept the Magni+ I was previously using.

 

[Dunring]

When you plug into a powered amp it creates a short, it's why most manufacturers recommend turning down the volume when switching. It's a fluke what happened though. Years in a business buying this gear, I've never even seen a Schiit amplifier or DAC for sale for parts or not working. Be glad it's local for the warranty, shipping to a factory in China is $60+

 

[Music1969]

it's why most manufacturers recommend turning down the volume when switching.

Isn't volume irrelevant to the smoke appearing?

Isn't the recommendation to plug and unplug when amp is off ?

 

[Doodski]

Sorry to see your new Schiit fried @Brian Hall. I have never unplugged my headphones ever ever so I don't know much about this. Looks to me like a warranty claim is about to be created. Let us know the progress.

 

[Brian Hall]

Sorry to see your new Schiit fried @Brian Hall. I have never unplugged my headphones ever ever so I don't know much about this. Looks to me like a warranty claim is about to be created. Let us know the progress.

I submitted a form for it with Schiit. I hope they will replace it. I really like the unit. I don't know about the unplugging thing. I've used headphones for years and never had an issue like that with any amplifier. The Magni+ is working ok for now. I have to turn it up a lot higher to get the same volume.

 

[Doodski]

I've used headphones for years and never had an issue like that with any amplifier.

Me neither. I have several dozen connect/disconnects on non-Schiit gear and no issues for me too.

 

[mc.god]

Meh, this reminds to me what I experienced with Magni 3+ back in the days...
https://audiosciencereview.com/foru...eresy-headphone-amp-reviews.10311/post-408376

https://audiosciencereview.com/foru...adphone-amp-reviews.10311/page-23#post-409216

 

[mhardy6647]

Historically, headphones were plugged into and unplugged from the appropriate socket on a preamp, integrated, or receiver with (so to speak) gay abandon.


I rarely if ever use headphones, so I don't have a handy photo to illustrate this, but here's a venerable vintage integrated amp proudly displaying its headphone socket : )

 

[Doodski]

Historically, headphones were plugged into and unplugged from the appropriate socket on a preamp, integrated, or receiver with (so to speak) gay abandon.


I rarely if ever use headphones, so I don't have a handy photo to illustrate this, but here's a venerable vintage integrated amp proudly displaying its headphone socket : )

It seems to be the high performance dedicated headphone amps that are frying. I never unplug my Schiit. I never power it off and it sits collecting dust behind my monitor never to be seen etc.

 

[mhardy6647]

So... What have "we" forgotten in engineering headphone outputs that "we" knew 30 to 50 years ago, when this never (AFAIK) happened?

 

[Doodski]

So... What have "we" forgotten in engineering headphone outputs that "we" knew 30 to 50 years ago, when this never (AFAIK) happened?

The big amps and receivers are using the voltage divider resisters and that might be the difference.
Refer to orange circled resistors leading to the relay that goes to the headphones. Most headphone circuits do not have the relay but this Yamaha does.

 

[solderdude]

Isn't volume irrelevant to the smoke appearing?

Isn't the recommendation to plug and unplug when amp is off ?

When you turn the volume down before (un)plugging there is no signal to 'short' so it is safe to plug in and out.
What can happen when unplugging is the right channel (ring) can be between the left output and ground.
The tip, being smaller in length, is rarely a problem.
When a socket is used that has little 'bumps' on the contacts this should not happen, this thus depends on the used socket.
This is a big advantage of (mini)XLR by the way.

Amplifiers with low output resistance that are shorted (there has to be signal on it for this to happen, hence the volume should be down, no signal to short) then a high current can occur and when the power supply voltage is high this means a high current AND high voltage are present IN the amplifier. High voltage x high current is high Wattage = lots of heat = damaged output device = smoke.

Turning down the volume or swicthing off will ensure this cannot happen.

When an amplifier has current limiters nothing should happen (when properly designed)

 

[Brian Hall]

When you turn the volume down before (un)plugging there is no signal to 'short' so it is safe to plug in and out.
What can happen when unplugging is the right channel (ring) can be between the left output and ground.
The tip, being smaller in length, is rarely a problem.
When a socket is used that has little 'bumps' on the contacts this should not happen, this thus depends on the used socket.
This is a big advantage of (mini)XLR by the way.

Amplifiers with low output resistance that are shorted (there has to be signal on it for this to happen, hence the volume should be down, no signal to short) then a high current can occur and when the power supply voltage is high this means a high current AND high voltage are present IN the amplifier. High voltage x high current is high Wattage = lots of heat = damaged output device = smoke.

Turning down the volume or swicthing off will ensure this cannot happen.

When an amplifier has current limiters nothing should happen (when properly designed)

I had no idea that would ever be necessary. I guess the Midgard is not as well designed as it should have been. I had been using an XLR cable on my headphones, but switched to the 1/4" cable so I could use it with my AVR for a while. I should have switched it back.

 

[DSJR]

I'm sure Schiit will see you right here. Jason's articles on headfi are fascinating and if I have it right, they've worked hard to make these units as safe on speakers and headphones connercted to them (depending on the unit) as safe on the connected devices as possible.

Good luck

 

[solderdude]

I had no idea that would ever be necessary.

It shouldn't ever be necessary. It is good practice to turn the volume down though.
Admittedly I never do this myself but it is not needed for any of my amps anyway.
A headphone amp should be able to handle a short. Certainly the ones that can drive very low impedance or high power headphones.

I am sure Schiit will replace the amp or repair it.

 

[Brian Hall]

I am sure Schiit will replace the amp or repair it.

Either would be great. Until they do I'll just use the Magni+. Still great sound and decent power, but no XLR inputs for headphones.

 

[Yorkshire Mouth]

Question. Does it at you’re not supposed to do this in the user manual?

 

[Brian Hall]

Just double checked. It does not say anything about turning the volume down or turning the unit off before plugging or unplugging headphones.

The only mention of the volume knob is "Turn it to the right to increase the volume. Stop before it hurts.".

 

[Yorkshire Mouth]

Just double checked. It does not say anything about turning the volume down or turning the unit off before plugging or unplugging headphones.

The only mention of the volume knob is "Turn it to the right to increase the volume. Stop before it hurts.".

Well, whatever the rights and wrongs of doing this, if it’s within manufacturer’s usage instructions, and it’s still under warranty, you should be good.

 

[mhardy6647]

The only mention of the volume knob is "Turn it to the right to increase the volume. Stop before it hurts.".

For the record -- I would have thought Schiit's guidance for setting volume levels would have echoed Calvin's dad's description of the determination of weight limits of bridges.

The notion that inserting or removing a headphone plug from its jack would cook an amplifier (or, I guess, its power supply) still strikes me as ludicrous. I would certainly hope that Schiit'd honor their warranty (which I assume extends for more than a month).

PS I guess this variant would be more ASR's speed...