[mattlach]

Alright,

A little background:

My setup:
Schiit Bifrost 2/64 --balanced--> Lokius --balanced--> OG Schiit Jotunheim amp.

The Jotunheim serves both as a headphone amp and as a pre-amp via single ended cabling to my Parasound 275 v.2 and SVS SB12-NSD sub.

I live in the northeast, and during the winter when it is cold out the RH inside, especially with heating drops down very low. Right now it is ~20% RH in my office.

Today, I was sitting with my speakers on, headphones disconnected, listening to a Teams meeting. One of my cats was being a huge pain in the ass so I grabbed her and held her in my lap petting her while listening to my meeting.

I reached for the volume knob of the Jotunheim to adjust the volume level so I could hear the meeting over her complaints at being confined to my lap, when I felt a very strong static discharge from my finger to the volume knob. It was strong enough that now 10-15 minutes later I can still feel it in my finger.

This resulted in a loud pop from the speakers and sub, and then silence.

Uh oh.

Silence when there is supposed to be sound is usually not a good sign.

I power-cycled everything, and it appears to be working again. I have done some listening tests, and nothing sounds off to me.

I'm guessing the large static discharge just triggered the over-current protection circuit, or something like that.

But....

Should I be concerned? Could I have done damage? I would imagine the case and knob go straight to ground, so it is unclear how it triggered the protection circuit, but while I am an engineer, I am not an electrical engineer.

I'd appreciate the thoughts of those who know more than I do on this subject.

 

[lantian]

Not expert, but in general,if the case is grounded any damage to electronics inside should be impossible. Of it's not grounded than all bets are off.
If it's still working your probably fine, though would be more careful in future if I where in your position.

 

[mattlach]

Not expert, but in general,if the case is grounded any damage to electronics inside should be impossible. Of it's not grounded than all bets are off.
If it's still working your probably fine, though would be more careful in future if I where in your position.

I'm pretty sure the case is grounded. It would have to be to pass electrical regs, I think. (not sure, not an expert)

But I wonder about that big metal cap on the volume pot. I bet it isn't grounded.

Would it be possible for a big discharge to jump into the pot and from there throughout the amp circuitry? Possibly.

As to being more careful? How do you do that? You can wear a grounding strap when working on electronics, but you can't wear one all the time....

 

[lantian]

If you truly build up a lot of static electricity then in your listening room just touch any other metal surface before touching the pot to discharge yourself, if case is grounded would touch the case before the pot.
If you have a 3 pin Power plug it's grounded.

 

[kh6idf]

[deleted]

 

[kh6idf]

I used to work with avionics boxes that go into airplanes. We had to be certified for handling static sensitive electronics. One thing I remember from the training was you can cause damage to sensitive devices by merely walking past them, 3 feet away and not touching them at all. The damage may not result in immediate failure, but may cause a failure some time in the future. So no real way to tell if your Jotunheim suffered any damage (it seems to be OK now), but if it suddenly fails some time in the future it might be due to that big ZAP.

An amusing incident I remember from the lab where I was working: We had a box that would reset sometimes if a button on the front was touched. In order to reliably demonstrate this to management, I sat in a wheeled office chair while my coworker pushed me across the lab at high speed to build up static. As I rolled past the box, I reached out and touched the button. That caused the box to reset every time. They put a grounded guard ring around that button to fix the problem

 

[TinearedOne]

My Vali 2 does that literally every time I forget to discharge static electricity prior to touching it, which I have done many times in about 8 years of ownership. Your Jotunheim will be fine.