FX Return Jack Fix for Sound & Static Problems

Intro to the FX Return Jack​

The FX Return jack of many amplifiers is often connected directly to the FX Send jack through a closed switch to allow the internal preamp signal to travel on to the power amp, when there is nothing plugged into the Return.

How It Works​

But, when there's a plug in the Return jack it opens that switch and interrupts the internal preamp signal from blending with the signal plugged into the Return and going to the power amp.

How It Malfunctions​

Dirt, dust or humid environments can cause corrosion build-up on the switch that interferes with the signal that normally passes through the closed switch (no plug in the FX Return). That corrosion can reduce, or even eliminate, the sound the amp would normally make, either intermittently or constantly. It can also add crackling or static to the amp's sound (or lack thereof).

How to Bypass​

With an instrument cable from the Send to the Return of the same amp, that switch is bypassed!

Diagnosis​

If the Bypass seems to completely solve the problem, that indicates a corroded FX Return switch is present. If the problem is only somewhat improved by the Bypass, then there may, or may not, be a corroded FX Return switch in addition to other problems.

Remedies​

1. First, try running the plug in-&-out of the FX Return jack several times to knock the corrosion off the switch. Then remove the cable from both jacks and listen to the sound while playing normally. That should improve the problem, at least somewhat.
2. If the sound is still somewhat reduced, or a bit crackley, it is time for a well qualified tech to look inside and either Clean or replace the jack. There may also be other problems needing repair.

It cannot be stressed enough to use only factory certified technical professionals for proper diagnosis and repair. Too often "some tech guy" may seem like a less expensive alternative, but may actually cause more problems than they repair!

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