Connecting FX send & return to fix amp problems......

[Beedster]

Just tried this with a rather perplexing problem and it did the tirck. So, why does this work?

 

On 05/01/2024 at 21:21, wateroftyne said:

Temporarily connect the FX send and return with a jack lead and report back…

[SimonK]

That's a pretty common fault when the switching jack sockets go (edit the switch is normally on the return). A small patch lead makes sure your send always goes to your return and the signal keeps running without the middleman so to speak!

Edited Tuesday at 17:21 by SimonK

[Beedster]

Thanks @SimonK but why does simply inserting a cable and then removing it do the trick?

[Norris]

The sockets get a bit mucky over time, and the contacts that normally touch when there is no jack in the socket can stop letting the signal. A short patch lead between the two sockets means you're not relying on those contacts and instead the signal travels through the cable.

 

A squirt of electrical contact cleaner in the sockets may be enough to clean up the contacts. The lead will still probably make a better contact though, because plugging and unplugging the lead will tend to keep the contacts clean.

[Beedster]

Thank you guys 🙏

[SimonK]

If I'm not using the effects send of an amp I almost always put a patch cable between send & return to avoid this problem which seems to happen to most amps over time.

 

Certainly one of the most joyous discoveries of an ebay/reverb bargain for a "broken amp" is when this little trick fixes the problem - but the aim is not to do it in the sellers presence!

[Beedster]

10 minutes ago, SimonK said:

If I'm not using the effects send of an amp I almost always put a patch cable between send & return to avoid this problem which seems to happen to most amps over time.

 

Certainly one of the most joyous discoveries of an ebay/reverb bargain for a "broken amp" is when this little trick fixes the problem - but the aim is not to do it in the sellers presence!

Indeed!

 

So is it simply a function of unused sockets, I’m still a little unclear on the actual cause? For example if it were simply an unused socket problem you’d not need to link send and return with a cable, just insert a plug? Am I being daft?

[pete.young]

32 minutes ago, SimonK said:

If I'm not using the effects send of an amp I almost always put a patch cable between send & return to avoid this problem which seems to happen to most amps over time.

 

 

 

Presumably this is not an issue for parallel effects loops since you still have a signal path which bypasses the loop?

 

I've also had success with spraying some switch cleaner on a jack plug and putting it into the socket a few times to lubricate the contact. This is a temporary bodge, leaving a cable there is a permanent bodge!

[SimonK]

2 hours ago, Beedster said:

Indeed!

 

So is it simply a function of unused sockets, I’m still a little unclear on the actual cause? For example if it were simply an unused socket problem you’d not need to link send and return with a cable, just insert a plug? Am I being daft?

 

Assuming it isn't a parallel effects loop as @pete.young says, there is an internal switch on the return socket detecting whether a cable is plugged in. So if nothing is plugged in the signal bypasses the effects loop altogether essentially internally routing send to return. This is where the fault you describe probably lies - the amp "thought" something was plugged into the return so cut the internal signal routing expecting a signal from the return which wasn't there, hence no sound. The "bodge" is to route the send to the return manually using a patch cable, or as you say, wiggle something in the return socket hoping that it's just some dirt that can be cleared!

[Beedster]

1 minute ago, SimonK said:

 

Assuming it isn't a parallel effects loop as @pete.young says, there is an internal switch on the return socket detecting whether a cable is plugged in. So if nothing is plugged in the signal bypasses the effects loop altogether essentially internally routing send to return. This is where the fault you describe probably lies - the amp "thought" something was plugged into the return so cut the internal signal routing expecting a signal from the return which wasn't there, hence no sound. The "bodge" is to route the send to the return manually using a patch cable, or as you say, wiggle something in the return socket hoping that it's just some dirt that can be cleared!

Thanks @SimonK so that’s why we don’t have similar issues with other old and unused sockets on the same amp?

[SimonK]

49 minutes ago, Beedster said:

Thanks @SimonK so that’s why we don’t have similar issues with other old and unused sockets on the same amp?

 

Depends on what the socket is supposed to do and what it is connected to internally! But as we have been discussing the failure of an FX return in particular is quite a famous cause for an amp to suddenly have no, or reduced, signal.

[tauzero]

Just to add - the switch on the return is actually one bent bit of metal in the jack socket resting on another bent bit of metal in the jack socket. When a plug is inserted, the top BBOM is lifted off the bottom one and the circuit broken. The surfaces that touch each other will gradually oxidise and eventually break the circuit. Inserting a plug will disturb the contact patch enough to start things going again but if you can easily get into the amp then contact cleaner on the return jack is the best way to go.