Tiny spark when connecting red/white RCA cable to amp

[Trillion]

Hello! Yesterday I purchased a Marantz PM6005 amp to pair with my Tannoy DCT6s. I have the amp hooked up to the line out of a Fiio E10K through a 3.5mm to RCA cable. The Fiio is connected via USB to my computer. I first connected the speaker cables to the speakers and then to the amp. Then I plugged the 3.5mm - RCA cable into my Fiio and as I was connecting the RCA end to the amp I touched the center post of the RCA cable against the outer sleeve section (ground?) of the amp's RCA input ports and noticed a tiny spark. The amp was switched off but plugged in and the Fiio was switched on (I was tired and forgot to turn it off). What exactly happened here? Could anything have gotten damaged? The same thing happened later when I was fiddling again but the Fiio was turned off this time (however it was plugged in to a computer which was switched on). I (probably pretty stupidly) tried the same thing with an old amplifier and couldn't emulate what happened. I'm really happy with the sound coming from the combination, just concerned and lacking in knowledge! Thanks for reading.

 

[steve_1979]

Hi and welcome to the forum.

As you've already mentioned it's good practice to turn everything off at the mains before connecting anything. It's also best to leave it turned off for a minute first to allow any built up energy to discharge before connecting anything too.

However the chances are that no damage has been done (I asume everything is still working fine?). Easy mistake to make and I'm sure we've all been there at some time. The worst is when connecting an RCA and you get that horrible loud crackling sound.

 

[Trillion]

Thanks for the reply and the welcome!

Everything is working absolutely superbly as far as I can tell, but I don't know whether these things either work or don't work, or they simply work less well! I'm a bit OCD when it comes to this stuff, just a shame I wasn't OCD enough to remember to turn the power off on the little Fiio! I think I read somewhere that the inputs on most electrical devices have zener diodes to protect the circutry against electrical damage? I'm pretty clueless myself when it comes to the intricacies of electronics, I just enjoy the sound.

 

[steve_1979]

Everything is working absolutely superbly as far as I can tell ...

I'm sure it's all fine then and you've got no worries.

Lesson learned for the future though.

 

[Trillion]

Yep! Seems to work great anyway. Now to decide between the built in DAC (which I was told was bad but sounds very good as far as I can tell) and the little Fiio..