The Dreaded Switching Jack Problem

[Jazz P Bass]

Here is a copy of an awesome article about switching jacks.
Courtesy and copyright of Mojo Music Supply.

[Jazz P Bass]

How do you make this a 'Sticky'?
The issue sure comes up enough.

[g-one]

Could the powers that be sticky it into the maintenance/troubleshooting section as well?

[Jazz P Bass]

Magic!

[priesty]

Yep, sorted this problem on a couple of Marshall combos dating from the 1990's by plugging a patch cable across the effects loop (fine if you are not using the loop).

[Andy]

5150's are known for this issue with their effects loop too. I've seen two myself.

[Enzo]

Every amp of any brand that has FX loops can have this. And the same problem can be in insert jacks on mixers or amplifiers. ANy jack that has the ability to interrupt the signal path has the potential to do this. Some amps like many Crate amps also have a footswitch jack that can have the same problem, only then it results in random channel switching or something lkek reverb going off and on. Whatever the footswitch functions are.

[Smitty02]

Nice..never ran across that one before but many other post about the dreaded issue....The secret is out ha ha...

[KCblues]

A friend advised me to use a burnishing tool to clean the oxidation from the contacts and then apply the Caig. I've found that technique to work great.

[imaradiostar]

Much like cleaning the contacts in Tektronix scopes, one could wet some paper with deoxit and run it between the contacts in the jack...but maybe that's what the article suggests? I'm sorry, I didn't take the time to read it.

I have seen this problem on quite a few amps.

jamie

[Smitty02]

LOL just to be clear I was speaking of the link you posted, that I have never ran across it. Yes Ive done many many dirty effects loops Vavletronix comes to mind for me as they are a newer-ish amp with these issues also resetting the thing works wonders, I also see amps that have so much crud on them you can tell they have never been cleaned or service'd, ever. Original tubes from the 90's ahh sovtek days. I usually do what I call a tune up, where I go through and clean everything test tubes and voltages caps..... I even scrub the cab or head up too One guy brought me a HRD in such bad shape with all the typical HRD issues, it wasnt working and looked like it was stored in a chicken coop for 3 years. when I finished it, he come to get it and didnt even know it was HIS amp, seriously... Needless to say he was very happy and gave me a tip to boot yee haw. Good link, but I hope everyone dont see it LOL.. Actually some guys are mechanical,,, but most wouldnt touch their own amps as well they should"nt if they are not comfortable doing so...

[guitician]

Or just ask Switchcraft to make the jack better? With none of that "Initial Quality" that means it will work at least until the warranty ends. Silver plating, or a tiny silver rivet at the contact point, would totally eliminate the problem.

[Enzo]

Actually silver tarnishes. The fact we see this problem doesn't mean there are not also millions of jacks that never do get the problem. I have had many amps come through needing the jacks to be cleaned - new amps. My working theory is that they got contaminated in the manufacturing process. Circuit boards get wahsed after the wave solder step, crap can accumulate betweeen contacts. Once I clean them, they never seem to come back for it again.


This happens to all brands of connector, Switchcraft, CLiff, you name it.

[guitician]

Yeah it tarnishes, but it's a conductive tarnish and the switch still works fine. I have a couple of old British made jacks were one has silver rivets as contacts, and the other has gold plating. And I remember sending off and email to Cliff asking them if they had gold plated 1/4" phone jacks and they said "yes, in qty of 1000 only". Why? Wouldn't you think that with all those gold plugs on cables you see being sold, that we could purchase gold jacks?

[Enzo]

If people were lining up to purchase them, they would not have them as special order items. The truth is there is little demand for gold flashed contacts. I can't say I ever saw a gold plated plug on a guitar cord. They may be out there, but I never saw one.

[guitician]

I guess people just like to clean contacts then, or have their techs do it. So, much for progress.

[52 Bill]

I've seen gold plated plugs, both 1/4" and xlr, not really worth the cost unless you're in the medical industry.

Yorkville sound specs gold plated contacts on most of their break jacks, but only on the contacts that are important. I don't think that I've seen that in any other product.

[Enzo]

Gold plated contacts are fine, as far as they go. They won;t tarnish, and offer low resistance. But that assumes all contact problems involve the metal condition. Gold will do nothing about dirt and film in the jacks. Certainly in clubs, the smoke gets so heavy that cigarette tar and nicotine condense on the surfaces and contaminate them. You can smell a club amp a milke away. Gold won't help.

[guitician]

I would think the spring tension of the gold contact would push through a film, and all it would take is a few molecules touching to get good conduction.

[gtrmann]

This is a real common problem down here in Florida. High humidity and non use of the jacks cause this here. The amp either goes up and down in volume, or cuts out completely... Cleaning the jack is the short term fix, replacing the jack will get you longer. Most guitar players and bassists don't know the jacks are there or ever know their use...

[Joe L]

Same thing here in Louisiana. Lots of humidity and occasional massive hurricanes.

For 35 years, I have used nothing but a strip of plain paper to clean contacts. Just pull it between the contacts with a little added pressure until it comes out clean and you are done. It is a gentle abrasive and won't remove plating.

[Jazz P Bass]

Here is a new post of the file.

[dbossman]

Hello All,

New to the forum. I am unable to view the pdf file which I assume has more detail in regards to a problematic switching jack. I have a Peavey Bravo 112 that the foot switch doesn't function. I have two other Peavey foot switches and they don't work either. I just bought the amp on CL and it worked intermittently when I first got it, than nothing. If I uplug the foot switch, I can switch the channels from the panel switch fine. What I have been able to determine from the thread is it appears to be oxidization of the jack. I am out of cleaning solution so am curious if this may be a possible issue. I haven't worked on compontent level electronics in over 20 years and am rusty (or oxidized ) and am not sure where the test points are to isolate the problem. Any ideas? I love the amp but really would like to be able to switch from clean to overdrive channel with foot switch.

Thanks,

dbossman

[Jazz P Bass]

I reposted the pdf directly above your post (the site has issues with archived files.)
http://music-electronics-forum.com/a...ck-problem.pdf
As to the Bravo footswitch problem, if the front panel switch works than the circuit is sound.
The jack or the front panel simply 'grounds out' the relay.
Plus the jack has a normally closed contact to allow the front panel switch to function when there is not a foot switch inserted.
Which must be functioning or the front panel would not work.
So that leaves the footswitch itself.
It is a simple 1/4" plug . Tip & Ring.
Tip to Ring should connect or not connect.
That can be checked with an ohm meter.