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Client dropped a Fender Vibro King for repair.
At moderate volume and above, and playing with a guitar, there is a slight flutter sound. I can only describe it as the sound of singing through a fan, like a very fast tremolo. Hear it on low and high strings.
It does it even when I go straight into the fx return. Changing the bias doesn't make a difference.
New tubes installed, and re checked. Only thing I didn't do was change the IC brand Capacitors.
The test fine with my ESR meter. Scoping the B+ rail i get a sawtooth of 16Vpp. There is a slight wobble of the falling edge trace when a 1khz sine signal is injected into the amp. (See video)
Any ideas?
At moderate volume and above, and playing with a guitar, there is a slight flutter sound. I can only describe it as the sound of singing through a fan, like a very fast tremolo. Hear it on low and high strings.
It does it even when I go straight into the fx return. Changing the bias doesn't make a difference.
New tubes installed, and re checked. Only thing I didn't do was change the IC brand Capacitors.
The test fine with my ESR meter. Scoping the B+ rail i get a sawtooth of 16Vpp. There is a slight wobble of the falling edge trace when a 1khz sine signal is injected into the amp. (See video)
Any ideas?
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