Can I damage my amp in this situation?

[frgmnt]

I'm wondering if I can possibly damage my headphone amp if I cut off its power, but still have signals coming in through the input and 12V trigger. I'm currently using a D50 III/A50 III stack hooked up to a P50 power supply. I have the DAC output through both the RCA(speakers) and TRS(A50 III) outputs at the same time. The stack is also hooked up through the 12V trigger. To save power, I have been shutting down the P50 to also turn off the headphone amp when I'm only listening to my speakers. Would this damage the A50 III since there is about 5Vrms running through the input, and whatever signal is running through the 12V trigger.

Would it also be bad to hook up the stack's outputs/inputs, and the 12V trigger while the units are on with with audio being played?

Looking through the manuals for both the DAC and amp, there are no warnings about doing any of this, so I'm not sure if it is possible to damage the amp or DAC in any of the situations described above.

I recently tried unplugging the 12V trigger, and I noticed the A50 III shutting off while audio is still being played. Most of the times this happens is when I put my headphones down and get up from my desktop. Not sure if I possibly damaged the A50 III during some time setting it up, turning it off while signals are running to it, or if it is faulty to begin with. I am not sure if the A50 III would've always behaved like this from the beginning, as I had the 12V trigger plugged in all the time preventing it from turning off while the DAC was on.

 

[amirm]

There is no risk. Ton of gear is run when off with the source first turned on.

 

[frgmnt]

There is no risk. Ton of gear is run when off with the source first turned on.

Thanks. I noticed the weird behavior with my A50 III and I was worried I might have shorted something due to voltage still running through the inputs and 12V trigger, or just by having that voltage running while the amp is powered off.

I've got another A50 III coming in to see if it behaves in a similar way. I'll avoid using the 12V trigger in the beginning, and if I get similar random shutdowns, I'll just keep the trigger plugged in. It seems to prevent my current A50 III from randomly shutting down.

 

[solderdude]

Most of the times this happens is when I put my headphones down and get up from my desktop.

Hmmm... sounds a bit like an ESD issue triggering a safety feature ?
Getting up from a chair can generate a lot of static charge.

Might seem silly but perhaps try to see if this also happens when you take of the headphones, put them on the desk and after that get up from the chair ?

ESD pulses (static charge) can do weird things with electronics and do not even have to 'generate sparks' to cause an influence. Have seen weird things happening with electronics during EMC testing equipment in ESD testing when digital circuitry is used.

Whether or not ESD can damage (or cause latent damage) is hard to say.

Connecting signals (incl. triggers) to non powered gear should not be problematic but depending on the type of circuit used inside a connected device it could easily be designed to be problem free but not all designs may like it.
When it is problematic for gear it would be logical for that gear to crap out after such an event or be very repeatable in behavior but may not be damaging.

 

[frgmnt]

Might seem silly but perhaps try to see if this also happens when you take of the headphones, put them on the desk and after that get up from the chair ?

This is what I mean. I haven't experienced it happening when I have my headphones are on. Only when I have them off, on the table and I get up from my chair. I had a SMSL RAW-MDA1 that acted similarly, and I had to restart that device along with any audio apps that were playing. The Fiio K7 and O2/ODAC I have did not ever do this.

I'm guessing the majority of the ESD pulses are coming from my chair rolling on my carpet. The carpet doesn't come into contact with my table at all, so I can only guess that there is a power line running underneath the carpet and wooden floor, and that somehow induces a ESD pulse through the power outlets.

Would a sine wave UPS or a power conditioner help with these problems?

 

[solderdude]

The most likely culprit is you getting out of the chair. It is impossible to get in the system through mains cables in or on the floor/carpet.

 

[Sokel]

I was testing an el.x-over with a cheapo 15-0-15 SMPS while sitting in a wool-silk carpet.
I could literally reset this thing just by rubbing my hand on the carpet and then touching it

 

[frgmnt]

The most likely culprit is you getting out of the chair. It is impossible to get in the system through mains cables in or on the floor/carpet.

There can be that much ESD traveling through the air to affect the electronics? Since this has been happening, I've made sure to not be in contact with the table. Just have my feet on the floor to push my chair out.

Having my humidifier on helps keep it from happening that often. Maybe some anti-static spray on my carpet and chair would help too.

 

[solderdude]

through the air is only possible when there is a spark which you would feel.
The human body can easily 'hold' 30kV but not much higher as that would 'leak' away.
2 synthetic pieces of cloth can easily generate 10kV or so.

Usually when you get 'zapped' by a static charge it usually is the person discharging to ground so it is the person that is charged and not the object one touches.
Of course, objects can also have some voltage on it when for instance safety ground is not present and there is some leakage.
The main difference is that a static discharge is short, one-time only where leakage from mains connected gear is repeatable and 'felt' every time you touch it.

 

[frgmnt]

The part that confuses me is how there is an ESD pulse when I'm not in contact with the table or any electronics. I do not feel like I am zapping anything, and I don't hear any zaps.