2. amps-preamps
  3. 194162-10279

Weird crackling from speakers when preamp connected

I've got an MC275 hooked up to a VTL 2.5 preamp, when I reconnected it after some maintenance, whenever I turn the preamp on then the amp, once they both warm up, the crackling starts.

I hooked up the amp to my DAC and had no issues with crackling, swapped tubes, interconnects and power cord, different inputs/outputs, same crackling issue when using preamp but no issue when connected to the DAC as a preamp.

Sonus Faber Olymica !, MC275 Amp, VTL 2.5 preamp, Auralic Vega DAC, nordost interconnects/speaker cables, panamax power conditioner.

My last step is to see if I can either borrow a tube preamp or buy a cheap one to test it.

Any suggestions are welcome as I'm running out of ideas.

 

maddog66blue
devinplombier
520 posts
 

Is there any pattern to the crackling sound, or rather does it appear kind of random / intermittent?

classic8
101 posts
 

@maddog66blue OP - I had a similar issue with a tube preamp;  I was getting intermittent static noise in one of the channels. It turned out to be a bad capacitor. The technician discovered the problem by nudging the capacitor with a wooden chopstick while the preamp was on.

maddog66blue OP
34 posts
 

@classic8 I'll take your suggestion. I'm surprised they didn't find anything wrong with it, but it's like taking your car to the mechanic.

classic8
101 posts
 

I sent the preamp to the manufacturer and he couldn’t figure it out (he retouched some solder joints, replaced a few resistors, and declared victory); luckily the local technician did.

yoyoyaya's avatar
yoyoyaya
879 posts
 

@OP Assuming the VTL has a non-captive mains, try a different mains cable. Also, try plugging into a different mains socket.

Check if any new source of RF could be present since you sent the pre for service.

Those are long shots as crackling is almost always a bad joint, cap or tube - but they are worth a shot on the basis of ruling things out.

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