Footswitch issues

[John Matrix]

I have been having a weird issue with an A/B switcher. It has two fx loops that can be switched between and a master bypass switch. I just use it to switch between two different distortion sounds. Sometimes when I step on the master bypass switch to turn the loops on the signal weakens a little bit. Its very subtle and only really noticeable because the distortion sound is less gainy than it should be, more like a mild OD. It doesn't matter which of the loops is active. To fix it, I can either click it off and on again, or sometimes I just need to press the bypass switch down part way and release it.

To me it seems like something wrong with the switch but when I emailed the builder they suggested that it might be bad cables. That doesn't really make sense to me based on the way it acts but I'm no expert. Anyone on here have any suggestions for fixing this problem? I can send the switch back to the builder but I'd rather just fix it myself if I can.

[crochambeau]

In my experience, switches have caused me more grief than any other aspect of building.

the builder // suggested that it might be bad cables.

Troubleshooting through instructing another to make observations can be problematic, and when something shows up for repair and exhibits no faults a headache ensues. It may be the builder is just trying to check all the boxes before proceeding in order to avert what could be wasted time & money.

It doesn't matter which of the loops is active.

Since it does not matter which loop is active, the main cabling you'd need to consider is main input/output - and you can probably assess the condition of that without touching anything and with the unit in bypass. Otherwise, if it's loop cabling, you have two intermittent cables that behave in an identical manner, and it only takes the physical impact of your foot on the bypass to "reseat" your cable/jack. Not outside the realm of possibility, but stacked issues tend to indicate a common cause.

To fix it, I can either click it off and on again, or sometimes I just need to press the bypass switch down part way and release it

Do you know what the signal path inside the box looks like? ie: is it latching true bypass mechanical switches, or do the switches actuate a relay or solid state switches (allowing momentary switch operation)? Different topologies invite different corners to troubleshoot.

From what you wrote, I would suspect the main bypass switch as well. Assuming it is a latching mechanical, does the click sound crisp and can you hear the spring reset (the smaller click when the plunger returns to rest). Excess grease on contacts shouldn't make a noise (unless the grease is entering into an adhesive state), but worn or broken pivot angles might feel a bit different (pointless test unless you have identical switches on hand to compare).

Good luck, it does sound like an easy fix.

[John Matrix]

Thanks for the info. The switches are the latching kind. I havent really sat down and gotten deep on testing it yet. The issue seems to happen kind of randomly, which as you mentioned, is one of the reasons I don't want to send it in to be fixed. I did open it up once and look inside and all the connections looked good. Anyway, I need to spend some time on this to narrow it down it seems.

[goroth]

I'd just reflow the solder on all the connections on the switches. I thought the switch on my Dr Scientist delay was dying. That dude is a pedal genius, and the soldering looked (and probably was) impeccable. But I reflowed the solder on all the connections and now it's fixed.

I've also "fixed" DC jacks like this.

Just touch a hot clean tinned tip to the lug, let the solder melt, remove the tip.

If that doesn't help chuck a pedal with a decent buffer in the loop with the pedal that is losing gain, just to see if it is some weird impedance bullshit.

If that still doesn't help check how the switch is wired. There are a couple of different ways to wire a bypass, and with a high gain circuit I'd want to make sure both the input and output were grounded when it was bypassed.