[amita]

When connecting the pre-out on my new Denon receiver (which was unplugged) to my Kef HTB2 active sub (which was unfortunately switched on) via the coaxial cable, there was a loud 'thump' from the sub. It all seems to still be working okay, sounds fine, but is there any theoretical risk of having damaged the receiver or the sub, or am I being ridiculous?

[mooperman]

i wouldnt worry about it, but someone here may think differently...

[amita]

Originally Posted by mooperman

i wouldnt worry about it, but someone here may think differently...

Thanks for your reply. I was probably being silly, but to reassure myself I just phoned Denon and Kef, and they told me that all should be fine, as the pre-out from the receiver is a one-way circuit and so should be fine. Kef told me that as long as the receiver sounds okay, then that should be fine too. Phew!

[lechacal]

Yes, there's a theoretical risk but then there's a theoretical risk from cosmic rays. Chances are you haven't done any damage. It's just not the sort of thing you want to repeat (not that you would).

[Nimby]

It is a bit risky to plug or unplug anything while something was switched on. If the sub is still performing as it was before then you may have got away with it. Don't do it again!

This is a common problem with the BFD EQ device. It makes a terrifying bang in the speakers or sub if it switched off first or on last. I had to print a list of which items to switch on and off and in which order. The problem is that many analogue devices have large reservoir capacitors which take a while to drain. So patience is definitely a virtue. Now I get told off if I make a thump!

[amita]

Originally Posted by Nimby

It is a bit risky to plug or unplug anything while something was switched on. If the sub is still performing as it was before then you may have got away with it. Don't do it again!

This is a common problem with the BFD EQ device. It makes a terrifying bang in the speakers or sub if it switched off first or on last. I had to print a list of which items to switch on and off and in which order. The problem is that many analogue devices have large reservoir capacitors which take a while to drain. So patience is definitely a virtue. Now I get told off if I make a thump!

Ahhh, I see, so when the amp is conected to the sub in the manner I did, the capacitors in the amp discharge, causing a thump? I've definitely learnt my lesson, and will never do it again!