Author Topic: EEVblog #1052 - BEWARE Crap Banana Plugs!  (Read 8527 times)

0 Members and 1 Guest are viewing this topic.

Online Dr. Frank

  • Super Contributor
  • ***
  • Posts: 1947
  • Country: de
EEVblog #1052 - BEWARE Crap Banana Plugs!
« on: January 20, 2018, 09:54:37 pm »
These multi contact plugs - LS 4 - are really high grade.
Got them on stock and in use  for > 25 years, practically no wear-off of the gold plating, of course also no corrosion.
I measured 0.02 ohm for a 50cm mc cable. They also have low thermal voltage.
You get what you pay for.

These slits in these plugs  might pose some problems nowadays on DMMs, if they have a switch detector in their jacks.
Therefore, MC obviously prefers round, slotted plugs nowadays.

Frank
« Last Edit: January 20, 2018, 10:16:07 pm by Dr. Frank »
 

Offline sleemanj

  • Super Contributor
  • ***
  • Posts: 2673
  • Country: nz
  • Professional tightwad.
    • The electronics hobby components I sell.
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #1 on: January 20, 2018, 10:11:23 pm »
I have encountered similar problems in the past

https://www.eevblog.com/forum/reviews/loosey-goosey-banana-plugs/
~~~
EEVBlog Members - get yourself 10% discount off all my electronic components for sale just use the Buy Direct links and use Coupon Code "eevblog" during checkout.  Shipping from New Zealand, international orders welcome :-)
 

Offline CDN_Torsten

  • Regular Contributor
  • *
  • Posts: 65
  • Country: ca
  • Professional electron whisperer
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #2 on: January 20, 2018, 11:07:06 pm »
I've had a similar problem - ordered a bunch of nickel plated ones.  They had the same intermittent contact as Dave shows in his video.  I didn't want to trash them, so I (very cleanly) soldered the tip-end of the spring.  They are now the best banana jacks I own.  ;D

-T2
 

Offline Rafael

  • Contributor
  • Posts: 42
  • Country: br
  • Your future hasn't been written yet. No one's has.
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #3 on: January 20, 2018, 11:21:50 pm »
Maybe someone can share some "trustable" links of good banana plugs!  :)
LTZ1000 for voltages, Emmett Lathrop "Doc" Brown for me.
 

Offline EEVblog

  • Administrator
  • *****
  • Posts: 32492
  • Country: au
    • EEVblog
 
The following users thanked this post: Rafael

Offline Rafael

  • Contributor
  • Posts: 42
  • Country: br
  • Your future hasn't been written yet. No one's has.
LTZ1000 for voltages, Emmett Lathrop "Doc" Brown for me.
 

Online beanflying

  • Super Contributor
  • ***
  • Posts: 5523
  • Country: au
  • Toys so very many Toys.
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #6 on: January 21, 2018, 01:08:11 am »
"Gold" isn't always gold.

I got a small batch of those same plastic topped bananas and the rotating part is magnetic so it is ferrous or steel. Most likely not cleaned properly before plating with whatever they used. So break out the magnet. ** Brass is 'slightly magnetic' to strong magnets but if you hit steel you will know.

Some of the other cheapies are still brass based however but it is a case of pot luck from ebay until you find the right ones. ?

There is a couple of good threads on Banana jacks and sockets in the Meteorology section of the forum too.

Good ones and good supplier  :-+
https://www.ebay.com.au/itm/12-pcs-Audio-Speaker-banana-plug-Audio-Jack-connector-24K-Gold-plated/112144340776?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
https://www.ebay.com.au/itm/10pcs-4mm-Gold-Connector-Banana-Plugs-Adapter-change-to-spade-Adapter/122385977092?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
https://www.ebay.com.au/itm/10set-5color-Gold-Plated-Brass-Stackable-4mm-Banana-Plug-Speaker-Cable-Connector-/253102319127?hash=item3aee12e617&_uhb=1

Coffee, Food, R/C and electronics nerd in no particular order. Also CNC wannabe, 3D printer and Laser Cutter Junkie and just don't mention my TEA addiction....
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20693
  • Country: nl
    • NCT Developments
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #7 on: January 21, 2018, 01:25:05 am »
Maybe someone can share some "trustable" links of good banana plugs!  :)
AFAIK Multi-contact is RS' or Farnell's own low cost bottom-of-the-barrel-to-be-avoided brand. Better stick to Hirschmann, Pomona, etc.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
The following users thanked this post: Rafael

Online beanflying

  • Super Contributor
  • ***
  • Posts: 5523
  • Country: au
  • Toys so very many Toys.
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #8 on: January 21, 2018, 05:16:46 am »
Timely actually got around to making some 19mm 2 wire shorting bars. The numbers shown are including contact resistance x 2 sets. All cheap chinese brass 'gold' plated contacts measured on my Quadtech milliohm meter.

The bars were soldered with 2% silver and cleaned first.

I have some gold flat shorting bars for the 3rd set underway.

EDIT - Made a set using the same looking plugs as in the video. 4-7 mOhms depending on how you wiggle it  ::)
Unlike Daves the plating on mine is clean but give it a little time and it is possible the base metal will corrode through the plating.
« Last Edit: January 21, 2018, 05:45:50 am by beanflying »
Coffee, Food, R/C and electronics nerd in no particular order. Also CNC wannabe, 3D printer and Laser Cutter Junkie and just don't mention my TEA addiction....
 

Online Dr. Frank

  • Super Contributor
  • ***
  • Posts: 1947
  • Country: de
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #9 on: January 21, 2018, 08:32:20 am »
Maybe someone can share some "trustable" links of good banana plugs!  :)
AFAIK Multi-contact is RS' or Farnell's own low cost bottom-of-the-barrel-to-be-avoided brand. Better stick to Hirschmann, Pomona, etc.

Utterly wrong & nonsense.
Multi Contact was/is a genuine Swiss brand, been taken over by Swiss company Stäubli.
They still make high quality connectors.
The ones shown by Dave and by me are brass spring with hard plated gold.
As said, very durable. I got rid of Hirschmann crap in the physics labs at university 30 years ago.

Frank
« Last Edit: January 21, 2018, 08:36:15 am by Dr. Frank »
 

Online Berni

  • Super Contributor
  • ***
  • Posts: 3375
  • Country: si
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #10 on: January 21, 2018, 08:41:31 am »
Yeah i know the problem pretty well on my cheap chinese banana plugs. They even became loose enough to cause problems with my 4 wire resistance test clips.

Here is my fix for it:
Get a big chunky soldering iron tip and solder the loose part to the body in just one point to create a solid connection. They might not spin as freely anymore but now they do keep a good connection when wiggled about.
 

Offline eevFinn

  • Newbie
  • Posts: 2
  • Country: dk
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #11 on: January 21, 2018, 10:50:46 am »
Hello everyone

Yes, I have them from eBay.
They have long been out of service here with me.
It's not just the coating it's wrong with.
On those David shows that works, the spring ring is open around the center pin.
The the one that does not work. Here the ends of the spring reaches each other. The spring clamps well on the bush but not on the center pin. They rotate freely and without friction. Had the manufacturer just made 0.1 mm gab, so the spring also had clamped on the center the pin it had worked well.
See the pictures with the green arrow.

Sincerely
Finn Johansen
OZ5HZ
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 20693
  • Country: nl
    • NCT Developments
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #12 on: January 21, 2018, 01:27:09 pm »
Maybe someone can share some "trustable" links of good banana plugs!  :)
AFAIK Multi-contact is RS' or Farnell's own low cost bottom-of-the-barrel-to-be-avoided brand. Better stick to Hirschmann, Pomona, etc.
Utterly wrong & nonsense.
Multi Contact was/is a genuine Swiss brand, been taken over by Swiss company Stäubli.
They still make high quality connectors.
The ones shown by Dave and by me are brass spring with hard plated gold.
As said, very durable. I got rid of Hirschmann crap in the physics labs at university 30 years ago.
Thanks for the info. I came across connectors from this brand on RS' website but I couldn't find a website and the datasheets where crappy so I defaulted into thinking it was a brand RS made up.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline BU508A

  • Super Contributor
  • ***
  • Posts: 2819
  • Country: de
  • Per aspera ad astra
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #13 on: January 21, 2018, 02:30:33 pm »
Here you can find technical information etc. for the MultiContact products:

https://www.staubli-test-measurement.com/

Usually I'm buying them at Bürklin:
https://www.buerklin.com/en
“Chaos is found in greatest abundance wherever order is being sought. It always defeats order, because it is better organized.”            - Terry Pratchett -
 

Offline alm

  • Super Contributor
  • ***
  • Posts: 1343
  • Country: 00
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #14 on: January 21, 2018, 04:11:52 pm »
Thanks for the info. I came across connectors from this brand on RS' website but I couldn't find a website and the datasheets where crappy so I defaulted into thinking it was a brand RS made up.
You might have been confused by the similarity to the Multicomp brand, which is a Farnell/E14 'value' brand.
 

Offline open loop

  • Regular Contributor
  • *
  • Posts: 52
  • Country: gb
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #15 on: January 21, 2018, 10:37:09 pm »
Interesting video...
It just goes to show with test and measurement you need measurement confidence. Looks like the confidence has been shattered a poor batch of conectors from Aliexpress/ebay (despite having previous good experience with Aliexpress/ebay). I really liked look of the connectors in the first Post from Dr Frank and I might give Staubli/MC connectors a go. The cost of these connectors are high but is saved when you don't spend the two hours chasing your tail when fault finding on a new product, project or repair.

I am however interested in what happens when materials are mixed even when making somethng as seemily simple as a shunt. I am thinking of the thermal electric effect this will be something to watch out for when measuring small voltages with a set of poorly designed test leads. Follow on Video idea Dave?
 

Offline ggchab

  • Frequent Contributor
  • **
  • Posts: 262
  • Country: be
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #16 on: January 22, 2018, 11:36:04 am »
Very interesting information. But poor sacrificed probes  :'(
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 10577
  • Country: au
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #17 on: January 22, 2018, 02:08:28 pm »
If you think sacrificing probes is cringeworthy, then you'd better not check out Dave's canyoning effort - or the things he will drop from the top of a dam wall.
 

Offline TRIO Test and Measurement

  • Contributor
  • Posts: 10
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #18 on: January 23, 2018, 10:31:45 pm »
At TRIO T&M we've been aware for sometime of the problem with Dave's connectors. Perhaps it's because we are not "young players" as Dave suggests will fall into this trap!!  However is Dave suggesting he is also young by just discovering this?

Where these connectors can really become an issue is when higher currents are used.  In teaching environments in technical colleges (TAFE) in Australia when electrical machines / transformer theory etc. are being taught, low voltages but high currents are used. These currents can be in excess of 10A. That's when the resistance in those connectors really becomes a problem.  There are education establishments we deal with than simply refuse to use the connectors that Dave has for this very reason.

So if anyone else does not want to fall into that trap and wants the same 18A rated test leads used in these higher current situations then check-out these.
https://www.triotest.com.au/store/search?controller=search&orderby=position&orderway=desc&search_query=stackable&submit_search=
 

Offline NiHaoMike

  • Super Contributor
  • ***
  • Posts: 6966
  • Country: us
  • "Don't turn it on - Take it apart!"
    • Facebook Page
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #19 on: January 24, 2018, 04:19:00 am »
Very interesting information. But poor sacrificed probes  :'(
They're just modded to work in regular banana sockets. He presumably still has a lot of unmodified leads for when the CAT rating really is needed.
Cryptocurrency has taught me to love math and at the same time be baffled by it.

Cryptocurrency lesson 0: Altcoins and Bitcoin are not the same thing.
 

Offline scorillo47

  • Contributor
  • Posts: 6
  • Country: us
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #20 on: January 24, 2018, 10:26:26 am »
I've encountered this many times, especially with cheap Chinese connectors.

The problem seems to be that with low-quality "gold" plating you end up having all sorts of oxides, especially after some heavy soldering of a wire which heats up the banana connector, increasing its oxidation. This is very visible in Dave's connectors.

The problematic oxidation usually occurs between the multi-connect sleeve and the inner pin - depending on the design of the connector, an insertion isn't going to scratch that oxide layer away, so you have some small (measurable) resistance

Here is my simple solution - carefully solder one end of the sleeve to the inner pin (preferably the one closer to the connector as it won't increase the diameter of the tip of the connector, making it hard to insert). Use plenty of flux (preferably RMA to remove any oxidation) and just enough solder that would "wick" between the sleeve and the pin, creating a permanent connection. Don't use too much heat as it may damage the plastic handle. If you used RMA fuix, at the end, don't forget to clean the flux with alcohol so it won't cause oxidation over time.



 

Offline ggchab

  • Frequent Contributor
  • **
  • Posts: 262
  • Country: be
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #21 on: January 24, 2018, 10:44:52 am »
Quote
They're just modded to work in regular banana sockets. He presumably still has a lot of unmodified leads for when the CAT rating really is needed.
It was a joke :) I also guess he has a lot of probes.

I would have cut them more neatly. But I know (well, I think) that mechanical stuff is not what Dave prefers  ;)
 

Offline Vtile

  • Super Contributor
  • ***
  • Posts: 1021
  • Country: fi
  • Ingineer
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #22 on: March 15, 2018, 05:17:41 pm »
Interesting video. I have a bit different outcome of my own analysis than Dave though. I'm pretty convinced that the real issue with the bad and "crackling" connection is not that much of the oxidation or loose (diameter wise) fit of that sleeve. The real issue is length of the sleeve vs. the groove it sits on. If you think what happens when you insert that plug to the socket, the socket will squeeze the sleeves diameter down and since it deforms (non-permanently) the length grows and the contact is made at the ends of the sleeve. In better quality ones the longitudinal fitting is much much better I have also "repaired" many of the cheap ones by squeezing the groove shoulders so the groove gets shorter.

These cheapest of the cheap ones are really bad though. I ordered 20 of them, they almost are worth of the $2 I paid. Mines are "yellow plated" iron.  :P
« Last Edit: March 15, 2018, 05:26:50 pm by Vtile »
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 10577
  • Country: au
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #23 on: March 16, 2018, 02:24:59 am »
The real issue is length of the sleeve vs. the groove it sits on. If you think what happens when you insert that plug to the socket, the socket will squeeze the sleeves diameter down and since it deforms (non-permanently) the length grows and the contact is made at the ends of the sleeve. In better quality ones the longitudinal fitting is much much better

That is my observation as well.  I have some banana plugs that have the sleeves spinning freely when in open air - but when inserted into a socket, they are compressed inwards and thus become longer.  The ends do make solid contact with the body, resulting in them locking hard and being unable to rotate at all, without ham-fisted wrenching of the plug.
 

Offline Seekonk

  • Super Contributor
  • ***
  • Posts: 1874
  • Country: us
Re: EEVblog #1052 - BEWARE Crap Banana Plugs!
« Reply #24 on: April 05, 2018, 06:01:26 pm »
I have the crappy chromish plate ones and they are certainly unusable as shipped.  I remove some of the sleeve material at the tip where the seam meets and solder them.  Plenty of room and no need to file the solder to get them to fit.  Nice solid connection. Better fit than most of the banana plugs I have.   I'm ordering more of them!
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf