Author Topic: Banana plugs and precision test gear (Read 6367 times)

Synthtech · « **on:** January 12, 2018, 11:06:35 am »

Hello everyone, I am a new member, I run a vintage synthesiser service centre in Sydney. I have been looking for decent banana plugs for some time now and I am finding that so many brands really do not make good contact due to the looseness of the compressible cage around the plug shaft. It’s tricky to make precision 4 wire resistance tests and very low current tests when I can never be sure that a slight change of tension of a lead won’t fox the reading. Does anyone have any suggestions for decent plugs that I can use to make up custom leads that do justice to high resolution bench meters?

kj7e · « **Reply #1 on:** January 12, 2018, 02:14:52 pm »

Various user installed banana plugs;
http://www.pomonaelectronics.com/index.php?pageNum_rsProduct=0&totalRows_rsProduct=86&i=prodsub&parent=HWARE&cat=BANANAPLGJCK&getDetails=

4 wire Kelvin test lead sets;
http://www.pomonaelectronics.com/index.php?i=prodmain&getDetails=1&parent=LOWVOLT

Great quality, but they cost more than the Chinese eBay parts.

Conrad Hoffman · « **Reply #2 on:** January 12, 2018, 03:48:46 pm »

The whole idea of a 4-wire measurement is it isn't sensitive to small changes in lead or contact resistance. Still, stay away from the cheap bananas and use Pomona.

Vgkid · « **Reply #3 on:** January 12, 2018, 04:24:41 pm »

For the price , I have observed good results with the 4mm "amass" soldered banana plugs.

Synthtech · « **Reply #4 on:** January 12, 2018, 08:41:46 pm »

Thank you everyone, I will go and look at the Pomona Staubli and Amass products, I hadn’t come across them before. Sorry for the slip on my first post, I should have posted this question in the test equipment forum rather than the metrology forum, I use 6.5 digit Agilent bench meters, not the stuff of metrology!

Le_Bassiste · « **Reply #5 on:** January 12, 2018, 08:45:21 pm »

Quote from: kj7e on January 12, 2018, 02:14:52 pm

...
4 wire Kelvin test lead sets;
http://www.pomonaelectronics.com/index.php?i=prodmain&getDetails=1&parent=LOWVOLT

Great quality, but they cost more than the Chinese eBay parts.

nope, these are complete junk. wires too stiff, no twist-protection on plugs, flimsy clamps w/o sufficient grip, useless ground lead, and exorbitantly overpriced. guess how i know

Synthtech · « **Reply #6 on:** January 12, 2018, 08:46:55 pm »

Quote from: Le_Bassiste on January 12, 2018, 08:45:21 pm

Quote from: kj7e on January 12, 2018, 02:14:52 pm

...
4 wire Kelvin test lead sets;
http://www.pomonaelectronics.com/index.php?i=prodmain&getDetails=1&parent=LOWVOLT

Great quality, but they cost more than the Chinese eBay parts.

nope, these are complete junk. wires too stiff, no twist-protection on plugs, flimsy clamps w/o sufficient grip, useless ground lead, and exorbitantly overpriced. guess how i know

Had a bad experience?

ywara · « **Reply #7 on:** January 12, 2018, 11:57:01 pm »

The biggest banana connector problem is mismatch between 4mm and standard plugs/jacks.

Stick with standard banana plugs and jacks and you will be fine. Stick with 4mm plugs and jacks and you will also be fine (although the quality tends to be lower on these newer market entries). Don't mix the two.

Unfortunately, banana connectors have migrated into commodity hardware a long time ago and substantial innovations aren't being made. There are suppliers out there making very nice machined crimp-style banana plugs with slotted contacts for specific applications, but the major players are sticking with 1920s stamped springs over 1950s machined bodies slammed together in a pre-WW2 machine. The guys maintaining these machines learned from the guys who maintained the machines that learned from the guys who made the machines.

hwj-d · « **Reply #8 on:** January 13, 2018, 10:09:15 am »

Quote from: Synthtech on January 12, 2018, 11:06:35 am

Hello everyone, I am a new member, I run a vintage synthesiser service centre in Sydney. I have been looking for decent banana plugs for some time now and I am finding that so many brands really do not make good contact due to the looseness of the compressible cage around the plug shaft. It’s tricky to make precision 4 wire resistance tests and very low current tests when I can never be sure that a slight change of tension of a lead won’t fox the reading. Does anyone have any suggestions for decent plugs that I can use to make up custom leads that do justice to high resolution bench meters?

That's why I bought these plugs a few days ago:
https://www.ebay.com/itm/Hohlbanana-Bananen-Stecker-8-Stuck-vergoldet-NEU/371561546502?hash=item5682cb4306:g:lskAAOSwDuJWztEH

dl1640 · « **Reply #9 on:** January 15, 2018, 10:02:32 am »

Quote

Occasionally we observe on the end of the DCV source gold plated banana plugs (Pomona, MC Contact, ... ): http://www.pomonaelectronics.com/pdf/d_2BA_2BC_1_02.pdf

one question:
why 2BA rated 300V and 2BC rated 1400V??

ConKbot · « **Reply #10 on:** January 16, 2018, 05:54:32 pm »

Quote from: dl1640 on January 15, 2018, 10:02:32 am

Quote
Occasionally we observe on the end of the DCV source gold plated banana plugs (Pomona, MC Contact, ... ): http://www.pomonaelectronics.com/pdf/d_2BA_2BC_1_02.pdf

one question:
why 2BA rated 300V and 2BC rated 1400V??

2BA is 18Awg twisted pair, (presumably 300v rated) 2BC is terminated to RG58/u which is good for 1400v (at least the belden RG58/u is)

Mind your polarity though,as the 1.4kv will be center to shield rating, not the shield to things contacting the jacket rating.

dl1640 · « **Reply #11 on:** January 17, 2018, 09:30:26 am »

Quote

2BA is 18Awg twisted pair, (presumably 300v rated)

hi
i use this very often, sometimes just twist red one and black one, can go up to 1000V such as in DMM calibration, very handy.
this is also 18 AWG
http://www.pomonaelectronics.com/pdf/d2948_1_01.pdf

still wondering why 2BA is 18 awg twisted rate for 300v

dl1640 · « **Reply #12 on:** January 17, 2018, 09:42:00 am »

Quote

That's why I bought these plugs a few days ago:

hi

why such plug? more contact area?

hwj-d · « **Reply #13 on:** January 17, 2018, 11:11:07 am »

Quote from: dl1640 on January 17, 2018, 09:42:00 am

Quote
That's why I bought these plugs a few days ago:

hi

why such plug? more contact area?

Yes, sits tight, reliable contact, compared to that punctually motion- and temperature sensitive feather contacts.
Despite good material (gildet beryllium copper, if buying the right ones) relatively cheap to build DIY metrology grade low EMF measuring connections/cables.

dl1640 · « **Reply #14 on:** January 17, 2018, 02:08:34 pm »

hi hwj

i saw some speaker cables use such plugs, i'd like to try them since you have positive comment about that. and sometimes to measure with low voltage below..100mv i use pomona low thermo lug these lugs are said to be a copper alloy which have small thermo effects. but such cable may not be able to source higher voltage..like above 300vdc by a 5700 calibrator, maybe because of its loading effects. i attached the picture.

anyway a banana plug is much handy than spade lug one.

hwj-d · « **Reply #15 on:** January 17, 2018, 04:22:30 pm »

Hi dl1640,

but as you know, be aware with high voltage and DIY cables in special with this type of hollow banana plugs.

Also there is another thread with more competent people as me for that:
https://www.eevblog.com/forum/metrology/diy-low-emf-cable-and-connectors/msg190302/#msg190302

dl1640 · « **Reply #16 on:** January 18, 2018, 04:06:03 am »

hi hwj

that's a long thread and i will enjoy it

btw another one i use is this, gold plated with angled cable insertion hole

http://www.pomonaelectronics.com/pdf/d1825-4897-4899-6545_101.pdf

hwj-d · « **Reply #17 on:** January 20, 2018, 11:12:13 pm »

Look at this.

In retrospect, Dave confirms my opinion to this crapy spring contact banana plugs. And, he uses as the better alternative those from me also proposed hollow banana plugs.

Bingo, and thanks to Dave, to point it out so clearly.

dl1640 · « **Reply #18 on:** January 21, 2018, 03:18:15 am »

Quote from: hwj-d on January 20, 2018, 11:12:13 pm

Look at this.

In retrospect, Dave confirms my opinion to this crapy spring contact banana plugs. And, he uses as the better alternative those from me also proposed hollow banana plugs.

Bingo, and thanks to Dave, to point it out so clearly.

Officially we cannot use YouTube in here


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Author Topic: Banana plugs and precision test gear (Read 6367 times)

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