Spirit Monitors cutting out

[marb67]

I have Spirit Absolutle 2 studio monitors connected to a Samson Servo 170 amp. This sin't strictly hifi but I am sure someone here can help. For some considerable time the sounds cuts in and out of the speakers at low volume. If I give the woofers a little tap they come on again. The only other thing that brings htem on agai is if I turn the volume up quite a bit. Low level volume and it's crackly and cutting out in both speakers. The wiring is sound so I have no idea if this is an amp or speaker issue.

Can anyone suggest what it could be please ?

 

[davedotco]

Either the voice coil is catching in the gap so it needs a bit of a 'kick' to get it going or you have an intermitant poor connection between the terminals and the voice coil, most likely the later.

The usual place for this to happen is where the 'braid' from the input terminals is connected to the voice coil, a connection usually formed by an 'eyelet' on the cone. Look behind the speaker cone to see this.

If you are compedent with a soldering iron, resolder these joints and while you are at it, redo the connection of the braids to the terminals.

 

[andyjm]

The speakers are two way, so while Dave's analysis would be correct for a single driver, as you have a woofer and tweeter in each speaker enclosure you would still hear the HF at low volume, even if the voicecoil in the woofer had got stuck or disconnected.

More likely is the 'idle' circuit in your amp that cuts in at low level and activiates servo circuitry to force the outputs to 0V. Turning up the volume will cause the idle circuit to deactivate and the sound to resume, and it is also possible tapping the cone will produce a voltage pulse back to the amp to deactivate the idle circuit - hence the symptoms you are seeing.

This is a feature of your amp, not a fault, though it is possble that the circuitry is cutting in at too high a level. The amp is really designed for pro applications - studio monitoring, clubs and so on. I guess the designers didn't expect it to be used at low volume.

 

[davedotco]

For the OP to check regarding the tweeter.

The power saving circuitry that mutes the output, with no signal present, is a relatively new feature and if crudely set could cause the problems as described by andyjm.

No such thing 'in my day' in the industry but it sounds very plausible. Never experienced anything like it myself but that said my Adam Actve speakers will switch to standby if no signal is detected for several minutes but this has, as yet, not been an issue despite a few very quiet late night sessions.