Strange rapid popping/clipping from Dynamo 500

[GazzBC]

New member here - tried a search on this but nothing was quite on point.

I have an older Dynamo 500 that I picked up used. Really impressed with it - quite musical and not boomy. However, it is exhibiting an odd problem. Occasionally and at random intervals, it will emit a series of rapid,loud pops or clicks - but only when there is no signal from the receiver. That doesn't mean it will never happen when there is a signal, but I haven't heard it do so yet.

It has occurred with two different receivers - an old Harman Kardon AVR and a new Sony STR receiver. It's a fairly long run of RCA cable (through the wall), but I asked for a double cable, so I have tried either and it makes no difference. The cable is most likely good, and it's not the receiver. It's a new smart home, so perhaps there is some signal triggering it and sending into Manchurian Candidate mode?

Any help would be appreciated - it's not a deal-killer, but it's a pain in the ass to have to remember to shut the subwoofer off when not in use.

Gazz

 

[sdolen]

New member here - tried a search on this but nothing was quite on point.

I have an older Dynamo 500 that I picked up used. Really impressed with it - quite musical and not boomy. However, it is exhibiting an odd problem. Occasionally and at random intervals, it will emit a series of rapid,loud pops or clicks - but only when there is no signal from the receiver. That doesn't mean it will never happen when there is a signal, but I haven't heard it do so yet.

It has occurred with two different receivers - an old Harman Kardon AVR and a new Sony STR receiver. It's a fairly long run of RCA cable (through the wall), but I asked for a double cable, so I have tried either and it makes no difference. The cable is most likely good, and it's not the receiver. It's a new smart home, so perhaps there is some signal triggering it and sending into Manchurian Candidate mode?

Any help would be appreciated - it's not a deal-killer, but it's a pain in the ass to have to remember to shut the subwoofer off when not in use.

Gazz

I had this happen to a lower end ML sub (MLT series) . ML sent me a replacement amp which remedied the problem for a year or two until it died again.

 

[GazzBC]

I had this happen to a lower end ML sub (MLT series) . ML sent me a replacement amp which remedied the problem for a year or two until it died again.

Thanks - given that it’s a used unit, looks like i’ll Just have to live with it.

 

[Tosh]

My immediate suspicion is that the long RCA cable is picking up some kind of airborne radio interference like a cell phone (in combination with the receiver disconnecting the sub output and thus leaving the RCA cable more susceptible to RF pickup).
What happens if you leave the sub on, but disconnect the incoming RCA cable at the sub? If you still get popping, then you could rule out the cables and anything upstream.

Editing to add that generally I recommend always to turn off any power amps before making any connection checks. So before disconnecting the RCA at the sub, first switch it off, then undo the RCA, and then switch the sub back on. That way you won't get a nasty thump when you unplug the RCA from a live sub.