Don't buy banana plug from this site

[Blumlein 88]

I removed glittering surface with knife and could see the color of copper inside and it starts conducting. Before doing this I tried to heat it up with the flame of lighter, but still it was not conductive. Surface was not easily flamable material.

View attachment 348759

https://1drv.ms/v/s!AiyXa0utMTg7trgy9OeA_ZEjFcMHpw

Okay, but come on man....what is so hard about putting something heavy enough on it or clamping it so it is held steady. You had trouble getting a tone in this last vid. I'm just telling from experience if you cannot get good contact you'll fool yourself now and again. I think scraping it made the surface less slick and you were a little more able to get enough contact. No way do I think that surface was non-conductive.

 

[GaryY]

Okay, but come on man....what is so hard about putting something heavy enough on it or clamping it so it is held steady. You had trouble getting a tone in this last vid. I'm just telling from experience if you cannot get good contact you'll fool yourself now and again. I think scraping it made the surface less slick and you were a little more able to get enough contact. No way do I think that surface was non-conductive.

or 10kg?

https://1drv.ms/v/s!AiyXa0utMTg7trg0es8wouPWbmeJoQ

 

[GaryY]

That's exactly why I asked that he post a picture of one of the plugs, where you can also see the dismantled cable.
It also makes no sense at all that the outer grub screw is screwed in further than the inner one, as you can see in the picture. Something is not right

Please read carefully following threads. It is quite confident that this product is defective.

 

[MAB]

Okay, but come on man....what is so hard about putting something heavy enough on it or clamping it so it is held steady. You had trouble getting a tone in this last vid. I'm just telling from experience if you cannot get good contact you'll fool yourself now and again. I think scraping it made the surface less slick and you were a little more able to get enough contact. No way do I think that surface was non-conductive.

I think OP, after perhaps a slow start, has proven that the surface is coated, shellacked, varnished, adulterated, or made of fake-metal. Not measurement error.

There are low-cost alternatives to the original WBT that work really well, and alternatives like Pomona plugs but the connector OP linked in the first post is not good.

 

[Roland68]

I removed glittering surface with knife and could see the color of copper inside and it starts conducting. Before doing this I tried to heat it up with the flame of lighter, but still it was not conductive. Surface was not easily flamable material.

View attachment 348759

https://1drv.ms/v/s!AiyXa0utMTg7trgy9OeA_ZEjFcMHpw

Judging from the video, it can only be a contact problem on the surface of the 4mm connector part. The mandrel you are measuring on only has direct contact with the 4mm plug at the front.
Presumably something non-conductive came onto the surface during production, e.g. glue from the transparent plastic cover, paint, surface protective oil or wax, Teflon spray for the machines, etc.
Presumably the cables would have worked if you had used them.

Clean the connectors with alcohol or acetone, but do not touch the plastic.

After the video it is clear that the connector conducts through and there is no internal break. The mandrel that expands the plug only has contact via the thread that is inside the expandable 4mm plug.

And I now suspect that the product is not defective.
The first video clearly shows that you have contact at the front of the mandrel, where else would this contact come from if the plug is defective or not continuous?

 

[GaryY]

Clean the connectors with alcohol or acetone, but do not touch the plastic.

I already explained in the thread above that I even heat it up with lighter flame to burn out usual organic material and I believe this should be stronger treament than alcohol or solvent.

 

[Sokel]

Can you do a little test?
Make a ring with a cable core (better a solid one),put it around it and screw the plug as if it was in the speakers.

Then measure the resistance between the down screws and the cable ring you made.

I'm really curious!

 

[Roland68]

Clean the connectors with alcohol or acetone, but do not touch the plastic.

I already explained in the thread above that I even heat it up with lighter flame to burn out usual organic material and I believe this should be stronger treament than alcohol or solvent.

On the contrary, you can make things worse with the flame. An open flame has no place on contact surfaces.
Contact surfaces are generally only cleaned with alcohol or special alcohol/cleaning solutions. Please don't be angry with me, but this kind of thing is well known in HF technology and the associated measurement technology.
Since it can also be an industrial residue based on oil, wax or Teflon, I would recommend acetone.

 

[GaryY]

On the contrary, you can make things worse with the flame. An open flame has no place on contact surfaces.
Contact surfaces are generally only cleaned with alcohol or special alcohol/cleaning solutions. Please don't be angry with me, but this kind of thing is well known in HF technology and the associated measurement technology.
Since it can also be an industrial residue based on oil, wax or Teflon, I would recommend acetone.

As also as car detailing Enthusiast, I have IPA and and there is no change. My current job project is developing 5G RFand I know some part of HF from 900MHZ ~2.7GHz behavior as well.

 

[GaryY]

On the contrary, you can make things worse with the flame. An open flame has no place on contact surfaces.
Contact surfaces are generally only cleaned with alcohol or special alcohol/cleaning solutions. Please don't be angry with me, but this kind of thing is well known in HF technology and the associated measurement technology.
Since it can also be an industrial residue based on oil, wax or Teflon, I would recommend acetone.

I did test with this setup. Nakamichi banana plug into ground- 12 AWG wire with fine copper(I don't have solid wire, but twist as much as I can) around banana plug-climping red probe with screw.

For working banana plug, it just beeps with soft touch. For the problematic ones, it doesn't look matter of resistance issue (with very poor precision of measurement instrument) , but only on and off. I see two possibilties. It beeps when I pull 12 AWG wire with some tension. So can be mechanical or very thin isoati9n layer which is chemically strong but mechanically weak.

P.S.) please don't ask me why i bought this l. I just wanted to drop wire down from speaker connector.

 

[Chromatischism]

As also as car detailing Enthusiast, I have IPA and and there is no change. My current job project is developing 5G RFand I know some part of HF from 900MHZ ~2.7GHz behavior as well.

That is good stuff. I went for Mother's CMX because it was more affordable. BTW these surface preps are more than just IPA.

 

[GaryY]

Just to complete test, I tried only with broken pin. Innerside is conductive, but outside not. Outside becomes conductive only by very hard pressure which can make scratch or dent. Soft or a little pressure didn't work. I don't know what they did with surface.

https://1drv.ms/v/s!AiyXa0utMTg7trhD2AX0LC7z7eynOQ

 

[kchap]

My 10 AWG speaker cables (gearIT) are too stiff and I ordered some plugs and sleeve from Ali. Before plugging in cable, I measured open short what I usually don't do, but 6 plugs out of 8 were not conductive. It looks inner pin for giving pressure is not contacting front insert or (looking) gold plating is not well done. And.....at least Front insert part is PLASTIC... It was not plasitc. But still no contact from climping screw part to insert.

Edit :
This case may not be in general and, to avoid unfair reputation to the similar product from other manufacturer, I add the link of this product.
Also title is editted.

https://de.aliexpress.com/item/1005005553230517.html?spm=a2g0o.order_list.order_list_main.10.5efb5c5fP2mo5q&gatewayAdapt=glo2deu

And here is the simple test.

https://photos.onedrive.com/share/3B3831AD4B6B972C!891950?cid=3B3831AD4B6B972C&resId=3B3831AD4B6B972C!891950&authkey=!AFecNujenrRmfqk&ithint=video

View attachment 348504View attachment 348505

Maybe there are from a different manufacturer, but I use new identical banana plugs and have had no problem. I did use "bootlace" ferrules on the multi-stranded cable. The choices for ferrules were a bit limited but I got by.

To measure the resistance you would need 2 good quality banana sockets (assuming each end has a plug). Insert the plugs, screw down the knurled screw pins so the connectors binds with the sockets and then measure socket to socket. You should also be able to measure between the knurled screw pins.

 

[GaryY]

Short report, seller refunded after showing video as proof.

 

[Roland68]

Short report, seller refunded after showing video as proof.

In the meantime, I spoke to the dealer who makes his cables with it.
Over 800 connectors and not a single failure or contact problem and each cable is measured individually.
Anyone who knows a little about the topic knows that an open flame is completely unsuitable for cleaning contacts, especially without protective gas.
Isopropanol would have been just right before you started using the open flame, but at this point only acetone will help (maybe).
But if they get the money back, the problem is solved for you.

 

[GaryY]

In the meantime, I spoke to the dealer who makes his cables with it.
Over 800 connectors and not a single failure or contact problem and each cable is measured individually.
Anyone who knows a little about the topic knows that an open flame is completely unsuitable for cleaning contacts, especially without protective gas.
Isopropanol would have been just right before you started using the open flame, but at this point only acetone will help (maybe).
But if they get the money back, the problem is solved for you.

I have used IPA for the plug what I didn't flame as well. Anyway, problem is solved as you wrote.
One thing I was not sure while I was testing plugs, it might not be detectable if test process is by inserting plugs into socket of measurement device. As I have shown in the last video, strong pressure on 4mm pin makes open to short though I am not able to measure precise ohmic resistance.