EEVblog #1052 - BEWARE Crap Banana Plugs! - Page 1
Forum section: electronics / general

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 20, 2018, 09:54:37 pm
content: 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

author: sleemanj
author_rank: Super Contributor
timestamp: January 20, 2018, 10:11:23 pm
content: I have encountered similar problems in the pasthttps://www.eevblog.com/forum/reviews/loosey-goosey-banana-plugs/

author: CDN_Torsten
author_rank: Regular Contributor
timestamp: January 20, 2018, 11:07:06 pm
content: 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.-T2

author: Rafael
author_rank: Regular Contributor
timestamp: January 20, 2018, 11:21:50 pm
content: Maybe someone can share some "trustable" links of good banana plugs!

author: EEVblog
author_rank: Unknown
timestamp: January 20, 2018, 11:39:24 pm
content: Quote from: Rafael on January 20, 2018, 11:21:50 pmAny of the brands from Digikey. Pomona is kinda the industry reference standard.https://www.digikey.com/products/en/connectors-interconnects/banana-and-tip-connectors-jacks-plugs/302?k=banana+plug&k=&pkeyword=banana+plug&pv183=1029&FV=ffe0012e&mnonly=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25

author: Rafael
author_rank: Regular Contributor
timestamp: January 20, 2018, 11:48:16 pm
content: Quote from: EEVblog on January 20, 2018, 11:39:24 pmThank you Dave!I'm going through here:https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1311.R6.TR12.TRC2.A0.H0.Xpomona+.TRS0&_nkw=pomona+banana+plug&_sacat=0Digikey is not very friendly with Brazilians.

author: beanflying
author_rank: Super Contributor
timestamp: January 21, 2018, 01:08:11 am
content: "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 supplierhttps://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.l2649https://www.ebay.com.au/itm/10pcs-4mm-Gold-Connector-Banana-Plugs-Adapter-change-to-spade-Adapter/122385977092?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649https://www.ebay.com.au/itm/10set-5color-Gold-Plated-Brass-Stackable-4mm-Banana-Plug-Speaker-Cable-Connector-/253102319127?hash=item3aee12e617&_uhb=1

author: nctnico
author_rank: Super Contributor
timestamp: January 21, 2018, 01:25:05 am
content: Quote from: Rafael on January 20, 2018, 11:21:50 pmAFAIK Multi-contact is RS' or Farnell's own low cost bottom-of-the-barrel-to-be-avoided brand. Better stick to Hirschmann, Pomona, etc.

author: beanflying
author_rank: Super Contributor
timestamp: January 21, 2018, 05:16:46 am
content: 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 itUnlike 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.

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 21, 2018, 08:32:20 am
content: Quote from: nctnico on January 21, 2018, 01:25:05 amUtterly 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

author: Berni
author_rank: Super Contributor
timestamp: January 21, 2018, 08:41:31 am
content: 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.

author: eevFinn
author_rank: Newbie
timestamp: January 21, 2018, 10:50:46 am
content: Hello everyoneYes, 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.SincerelyFinn JohansenOZ5HZ

author: nctnico
author_rank: Super Contributor
timestamp: January 21, 2018, 01:27:09 pm
content: Quote from: Dr. Frank on January 21, 2018, 08:32:20 amThanks 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.

author: BU508A
author_rank: Super Contributor
timestamp: January 21, 2018, 02:30:33 pm
content: 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

author: alm
author_rank: Super Contributor
timestamp: January 21, 2018, 04:11:52 pm
content: Quote from: nctnico on January 21, 2018, 01:27:09 pmYou might have been confused by the similarity to the Multicomp brand, which is a Farnell/E14 'value' brand.

author: open loop
author_rank: Regular Contributor
timestamp: January 21, 2018, 10:37:09 pm
content: 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?

author: ggchab
author_rank: Frequent Contributor
timestamp: January 22, 2018, 11:36:04 am
content: Very interesting information. But poor sacrificed probes

author: Brumby
author_rank: Unknown
timestamp: January 22, 2018, 02:08:28 pm
content: 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.

author: TRIO Test and Measurement
author_rank: Contributor
timestamp: January 23, 2018, 10:31:45 pm
content: 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=

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 24, 2018, 04:19:00 am
content: Quote from: ggchab on January 22, 2018, 11:36:04 amThey'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.

author: scorillo47
author_rank: Newbie
timestamp: January 24, 2018, 10:26:26 am
content: 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) resistanceHere 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.

author: ggchab
author_rank: Frequent Contributor
timestamp: January 24, 2018, 10:44:52 am
content: QuoteIt was a jokeI 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

author: Vtile
author_rank: Super Contributor
timestamp: March 15, 2018, 05:17:41 pm
content: 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.

author: Brumby
author_rank: Unknown
timestamp: March 16, 2018, 02:24:59 am
content: Quote from: Vtile on March 15, 2018, 05:17:41 pmThat 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.

author: Seekonk
author_rank: Super Contributor
timestamp: April 05, 2018, 06:01:26 pm
content: 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!

author: trebejo
author_rank: Contributor
timestamp: May 13, 2022, 11:25:10 pm
content: Ithe temptation to post this, necrology is not to my taste, but good suppliers from The Big Country are so good to find... nonetheless, my apologies to the necro-averse.Quote from: beanflying on January 21, 2018, 01:08:11 amThank you so much for this, you have saved me much doubt and hesitation.Alas, ebay links are not permanent...is the supplier called panpa1688? I found it by searching for that "10set-5color" title and it was still intact. I would post the apparent current version (USA) of that ebay link, but then...Ok, but like I said, not permanent:https://www.ebay.com/itm/284616540836.

author: thm_w
author_rank: Super Contributor
timestamp: May 16, 2022, 08:50:30 pm
content: Quote from: trebejo on May 13, 2022, 11:25:10 pmI would be tempted to just go for this style instead, very strong springs:https://www.aliexpress.com/item/4001072043961.htmlEven the genuine ones are not terribly expensive, but they may not be easily available outside of europe.Although I do like the angled entry part.These also look interestinghttps://www.aliexpress.com/item/32872176812.html