LM402 - Is this a defect?

Genazvale

Junior Member
Was changing the head for the first time and noticed this flaw. There're 3 of them, actually, in different places. Is this normal?

20200716_125512.jpg
 

KamaK

Platinum Member
This looks like the spot(s) where the wire hangars contact during the copper/chrome electro plating process.


Look at the coin at shortly after the 7 min mark. You see the marks around where the alligator clip was? It's where the negative charge was applied.

Same for mass-manufactured things like snare drums. The cathode contact area is always gooched unless you constantly change the contact point (and it will still be a bit gooched regardless)
 
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Genazvale

Junior Member
This looks like the spot(s) where the wire hangars contact during the copper/chrome electro plating process.


Look at the coin at shortly after the 7 min mark. You see the marks around where the alligator clip was? It's where the negative charge was applied.

Same for mass-manufactured things like snare drums. The cathode contact area is always gooched unless you constantly change the contact point (and it will still be a bit gooched regardless)
Yes, I thought it was something like that, or maybe something they used for hanging it. But aren't they supposed to clean it after that?
 

KamaK

Platinum Member
Yes, I thought it was something like that, or maybe something they used for hanging it. But aren't they supposed to clean it after that?
They can't "clean" it as it's not dirty. It's simply due to the difference in impedance in areas local to the cathode conductor placement... Like when you copper-plate a nickel and the contact area turns black.

You can lower the current and raise the duration at the risk of undercoating the areas that are distant.... You can increase the number of cathode contacts... You can put it on cathode rollers and constantly change the contact points.... All of these solutions only mitigate the the appearance of the marks, take longer, cost more, and are less prone to automation...
 

TJK

Well-known member
Sigh, unfortunately it’s a thing that happens. Does it sound ok? If it speaks to you keep it. Sometimes Ludwig will give you a bastard that’s just not right. I’ve owned many supra, and the imperfect ones I have kept 😉
 

Genazvale

Junior Member
Sigh, unfortunately it’s a thing that happens. Does it sound ok? If it speaks to you keep it. Sometimes Ludwig will give you a bastard that’s just not right. I’ve owned many supra, and the imperfect ones I have kept 😉
Well, I'm still searching for its best sound, actually. Replacing the original snare head improved it a lot, but not yet perfect to me.
 

TJK

Well-known member
Well, I'm still searching for its best sound, actually. Replacing the original snare head improved it a lot, but not yet perfect to me.
replace the plastic straps with strings or the fabric stuff you will notice a less choked sound when laying into it
 

David Hunter

Junior Member
This looks like the spot(s) where the wire hangars contact during the copper/chrome electro plating process.


Look at the coin at shortly after the 7 min mark. You see the marks around where the alligator clip was? It's where the negative charge was applied.

Same for mass-manufactured things like snare drums. The cathode contact area is always gooched unless you constantly change the contact point (and it will still be a bit gooched regardless)
That was fascinating.
 
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