In a desire to upgrade the amplifiers we have for the sound system (folk musicians) We got 2 Spider V20 (NOT Mark II) amplifiers.
The mixer is a Yamaha MG82cx - 8 channel, phantom power. etc.
When the amps are both connected to the mixer, when powered on - the amps have a high-pitched oscillating noise that sounds like something from a 1950's sci-fi movie.
Troubleshooting so far: (None eliminates the sound)
* Swapped amps and outputs
* Set the selector to acoustic /clean and turned off the effects settings.
* Tried different and brand-new cables.
* powered on one amp at a time
* Tried with the mixer board powered off.
* Used a splitter to connect both amps to one output channel.
* Connected mixer and amps direct to wall power and different power strips
No oscillating sound when:
* One Spider V20 and a different amp.
* 2 non V20 amps
* Only 1 V20 connected to either output
Suffice it to say - I'm having a hard time figuring out this one.
Any suggestions are welcome.
