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02-09-2025, 12:32 PM
Hi Guys
Oxidised jacks were mentioned in post-2. The problematic jack is usually the one that is never cycled inasmuch as a cord is always in it or never in it. The contacts oxidise and at the point where the status of the cord is changed, the oxidation acts like a rectifier, imposing a threshold over which the signal has to overcome or "break through". This happens a lot with effects loops, as TUTs report.
In an amp like the 800 with the High and Low jacks, the contacts on the Low jack are never cycled and build up oxidation. The High jack closed contact for the tip merely shorts the input with no cord plugged on, so that tends to be less problematic.
An issue with every plastic jack, especially with the smaller square ones made by Switchcraft and others, is that the spring tension of the contacts is fairly low. A few cycles or the simple passage of time shows off the weakness of the design. 3mm minijacks are exponentially worse and are ubiquitous with computer and mobile equipment proliferation.
The open-frame jacks of yore have larger components and generally better spring tension. Their weak point is that all the components are held together by a crimp of the sleeve end. Rotation of the wafers and metal parts can cause a short between things that should not be shorted, and it also makes it more difficult to tighten the jack in the chassis hole.
Have fun
Oxidised jacks were mentioned in post-2. The problematic jack is usually the one that is never cycled inasmuch as a cord is always in it or never in it. The contacts oxidise and at the point where the status of the cord is changed, the oxidation acts like a rectifier, imposing a threshold over which the signal has to overcome or "break through". This happens a lot with effects loops, as TUTs report.
In an amp like the 800 with the High and Low jacks, the contacts on the Low jack are never cycled and build up oxidation. The High jack closed contact for the tip merely shorts the input with no cord plugged on, so that tends to be less problematic.
An issue with every plastic jack, especially with the smaller square ones made by Switchcraft and others, is that the spring tension of the contacts is fairly low. A few cycles or the simple passage of time shows off the weakness of the design. 3mm minijacks are exponentially worse and are ubiquitous with computer and mobile equipment proliferation.
The open-frame jacks of yore have larger components and generally better spring tension. Their weak point is that all the components are held together by a crimp of the sleeve end. Rotation of the wafers and metal parts can cause a short between things that should not be shorted, and it also makes it more difficult to tighten the jack in the chassis hole.
Have fun
