Anyone ever experienced electrostatic shock from NAC552 case...?

It's more likely you Ken rather than the amp. You've built up some static charge walking around etc and discharged it when touching the pre-amp. The air might have been very dry at the time (low humidity due to weather conditions), you were wearing thick soled shoes, nylons carpets etc. Might be worth checking humidity levels in the house if this is a regular problem and just leaving a few bowls of water around the house if humidity levels are low.  

It has happened before - including all the panel lights coming on and locking up the logic controls.  As James says, it's you discharging your static onto the NAC552 (nicely earthed).  A power cycle should clear it and have the 552 working normally again.

The 552 seems to be prone to this phenomenon Ken. It's happened to mine (and others I've touched) a few times. A simple button press (of the required source) generally restores normality. I've experienced nothing sonically deleterious when it's happened.

My 552 did come over all (sonically) peculiar many years ago and had to take a trip to meet its maker as I've told you, but I didn't get the visual Deus ex Machina or Ghost of Vereker (!) effect on that occasion.

What larks. Good listening.

John.

Just for 'reference', is there something different about the 552 case compared to other Naim components which leads to this behaviour? Or is any 'naimee' likely to get a new hair style if they approach their kit in wellington boots?

Yes, it's anodised aluminium as opposed to painted. Also the knobs are anodised aluminium. 

It's all the £50 notes rubbing against each other in 552 owners' pockets that generates the static charge. We plebs don't have that issue so don't suffer the same electrical discharge. 

Yep, I've also gotten a fair old whack from my 552 Ken. For a while afterwards it worked like a kind of aversion therapy; I found myself creeping up to it and rapidly banging it with the flat of my hand. Definitely down to what you happen to be wearing - since I've given up wearing my one-piece lycra jumpsuit the problem's not reoccured.

I've yet to have that problem with my 552  

It’s small karma shock sent by all 200 users... we are jealous!

actually what happened is that one end of an unconnected ethernet cable that was hanging on a hook on the bookshelf directly above my system touched the 552 case when i picked it up to use it elsewhere (i.e. i didnt actually touch the 552 case directly). there was one mighty frightening crack of what i believe was electrostatic discharge. all front panel lights went on, and as i said above, were back to normal after a powercycle.

however, sadly, the sound was pants after that.  Said 552 has been to Naim HQ where they replaced all DIN sockets plus other changes on the head unit and 552PS and its back sounding like a 552 should now...

enjoy

ken

Emre posted:

It’s small karma shock sent by all 200 users... we are jealous!

If you'd said that in the first place...

What was the other end of the Ethernet cable connected to ?

james n posted:

If you'd said that in the first place...

What was the other end of the Ethernet cable connected to ?

Was it a NAS streaming Van der Graaf Generator ?

Electrostatic charging of an unearthed case is possible, but I am not sure what in the 552's construction might do that (maybe Naim can confirm whether there is anything specific about its design and construction  that has that effect). Far more likely the shock will be from you, not the 552, typically  your body having become charged by walking across a carpet, then discharged giving you a shock when touching an earthed object , so the equipment is not itself giving you a shock, but your body is discharging to the equipment. 

The charcteristics of the listening room will be of key significance, e.g walking on a carpet with certain types of footwear sole material, and is worse in very dry air. Electrostatic discharge is a primary cause of destruction of sensitive semiconductors in equipment such as computers - and DACs etc -  after removal of the case, which is why precautions are essential for people servicing the. But in well-designed equipment the discharge is isolated from the sensitive components, so more a nuisance to the user than the equipment.

james n posted:

If you'd said that in the first place...

What was the other end of the Ethernet cable connected to ?

as i said, nothing. this was a completely free unconnected cable handing on a hook on my bookshelf above the system. when i picked it up to use elsewhere, one end touched the 552 case and, POW!!!!

enjoy

ken

Innocent Bystander posted:

Electrostatic charging of an unearthed case is possible, but I am not sure what in the 552's construction might do that (maybe Naim can confirm whether there is anything specific about its design and construction  that has that effect). Far more likely the shock will be from you, not the 552, typically  your body having become charged by walking across a carpet, then discharged giving you a shock when touching an earthed object , so the equipment is not itself giving you a shock, but your body is discharging to the equipment. 

The charcteristics of the listening room will be of key significance, e.g walking on a carpet with certain types of footwear sole material, and is worse in very dry air. Electrostatic discharge is a primary cause of destruction of sensitive semiconductors in equipment such as computers - and DACs etc -  after removal of the case, which is why precautions are essential for people servicing the. But in well-designed equipment the discharge is isolated from the sensitive components, so more a nuisance to the user than the equipment.

 

i actually have conductive mat (the ones sometimes used on electronic service bench)  in front on my rack, so would assume this would discharge any static from me. i have never suffered this problem before and at my age, i rarely buy new clothes --  and definitely not Lycra Tony! :-) But hey, who knows....

thanks for your thoughts anyhow.

enjoy

ken

So it was still you discharging static but via the cable you'd just picked up when it touched the case....

Blimey! I was considering a Lycra onesie. No chance after reading this!

james n posted:

So it was still you discharging static but via the cable you'd just picked up when it touched the case....

i suppose that's possible.

i also just wondered whether the fact that i had a separate earth for the hifi is relevant here. the earth wire from the CU (effectively, incomer earth) was not connected to the hifi sockets, instead all the hifi sockets were connected to this dedicated earth. But please,  lets not turn this thread into a discussion about mains/dedicated earth etc...

enjoy

ken

nigelb posted:

Blimey! I was considering a Lycra onesie. No chance after reading this!

Oh my god......

J.N. posted:

The 552 seems to be prone to this phenomenon Ken. It's happened to mine (and others I've touched) a few times. A simple button press (of the required source) generally restores normality. I've experienced nothing sonically deleterious when it's happened.

My 552 did come over all (sonically) peculiar many years ago and had to take a trip to meet its maker as I've told you, but I didn't get the visual Deus ex Machina or Ghost of Vereker (!) effect on that occasion.

What larks. Good listening.

John.

thanks John. i must admit i didnt expect this to cause a problem in my case, but it did.  just pure bad luck i guess...

enjoy

ken

It is unlikely to be Lycra related more that you were wearing wool - trousers perhaps or a jumper! Wool carpet doesn't help either. 

Being the poor owner of only a 252 static discharge is not an issue with the stereo, but I often give the dog an unwelcome spark when returning home from work, and regularly get discharges to the car when wearing my business attire!

thanks Listener72...

listener72 posted:

It is unlikely to be Lycra related more that you were wearing wool - trousers perhaps or a jumper! Wool carpet doesn't help either. 

Being the poor owner of only a 252 static discharge is not an issue with the stereo, but I often give the dog an unwelcome spark when returning home from work, and regularly get discharges to the car when wearing my business attire!

 

As I too own a 252 does that mean I can go for the Lycra onsie after all?

It is of course possible I need fashion advice rather than hifi advice. I'm off to the GQ forum.

My purple and green lycra one-piece jumpsuit came with the 552. The Naim logo's worn off a bit now, but as I was wearing it every day I'm still impressed with its longevity.