Cheap probe leads and banana plugs - UK Vintage Radio Repair and Restoration Discussion Forum

WaveyDipole · 20th Jan 2022, 7:10 pm

Does anyone know what metal is used for the wires in cheap probe leads? I recently purchased a cheap set partly because I needed to cut the ends off and replace them with banana plugs to fit my AVO.

The wire inside the insulation was thinner than might be imagined from looking at the leads and although the metal it looks superficially like copper, it has a tarnished and dull appearance. If you scrape it or clean it, the bare wire has a rather antique colour and doesn't have the usual bright shine of 'proper' copper wire. What is it made of? Since I purchased cheap it is perhaps no surprise that the overall resistance of the probe leads adds about 2.2ohms rather than the more typical 0.3 ohms.

Then there are the banana plugs. Does anyone sell decent ones these days? Ok, I know that Farnell, CPC and the likes probably do, but unless I place an order to a minimum value the postage cost tends to be rather prohibitive. They used to have quality mouldings and a well machined solid split pins that fit snugly into the moulding and the intended socket. The modern ones tend to be hollow, spring loaded and rather loose and wobbly for most part and with poorly machined threads for the clamping screws to boot.

Alternatively, can one still get probe leads without the shrouds? I have not been able to find any. Is this because health and safety prohibit that these days?

G6Tanuki · 20th Jan 2022, 7:48 pm

I make-up my own leads using the likes of

https://uk.farnell.com/belling-lee/l...-3mm/dp/317100

or the Hirschmann versions

https://uk.rs-online.com/web/p/banan...ectors/1902684

and their red equivalents, fitted to silicone-jacketed braid-core ultra-flexy cable.The results are good - I use them to do ad-hoc patching between various HF antennas and their tuners - squirting a couple of hundred Watts of RF on 3.5MHz and they have never melted,.

dodgy-dxer · 20th Jan 2022, 7:54 pm

https://www.cricklewoodelectronics.c...ckets-4mm.html

Lucien Nunes · 20th Jan 2022, 9:53 pm

I have made AVO compatible probe leads by simply cutting the shrouds off normal ones with a Stanley knife.

Your dull-looking wireh might be copper-clad aluminium, hence its very high resistance. If you sand it rather than scrape it you can get the Al to show through the Cu easier. Or possibly it's impure copper i.e. not electrical grade. Either way it's a bad material for test leads.

There are four main kinds of 4mm plug contact: Bunch pin, Single leaf or wire spring. Lantern contact and split pin. Of these, I find the lantern the most troublesome, not least because there are two contact interfaces in series: pin to lantern and lantern to socket. What often happens is that the lantern makes good contact with the socket but rattles about on its own support pin. I actually have some new UK-sourced test leads with this problem that I need to return, OTOH I have some direct-from-China copies of Hirschmann leads with large CSA copper cores and good, tight lantern plugs.

The cross-hole Hirschmann connectors linked above are good and highly rated. There is a low-cost copy by Farnell own-brand Multicomp that seems to work well: https://cpc.farnell.com/multicomp/a-...ack/dp/CN15642

I still quite like the basic Deltron single-spring type. They only make two points of contact with the socket but two good ones are better than a bunch of bad ones. If the plug is tight you know that the pin itself is pressed firmly against the socket wall. And the indirect cable entry and termination is reliable. https://cpc.farnell.com/deltron-encl...ite/dp/CN15656

The Philpott · 20th Jan 2022, 10:51 pm

Quick tests for thin wire suspected of being copper plated aluminium- if strands are manually bent they tend to spring back, and subject to a flame they disintegrate.
Dave

Refugee · 21st Jan 2022, 12:41 am

Those cheap leads are more likely to be copper plated steel.
It is not worth buying leads to chop up for the wire.
You can get a whole reel of real test probe wire for £20. It is 50 strand.
https://uk.rs-online.com/web/p/test-lead-wire/2101261

eddie_ce · 21st Jan 2022, 11:01 am

As in post #2 I tend to make up my own leads using very finely stranded, highly flexible silicon coated wire and Hirschmann plugs. I tend to solder these on to the cable rather than use the grub screws available on some versions as I have found that these can come loose with time.

ChristianFletcher · 21st Jan 2022, 11:58 am

Not on test leads but I have encountered the copper plated steel in cheap gear from china very frequently.

WaveyDipole · 21st Jan 2022, 1:21 pm

Thank you for the replies. I have attached a photo of the end of the wire in question. You can see how dark it is before cleaning near the insulation. I have seen very old wire look like this, but not brand new which is one reason why I asked. Copper plated steel perhaps makes more sense. I suspect that aluminium would have been more fragile. In any case, readings made with the probes also appear to be unstable and fluctuating so they are going in the bin. Their appearance looked the part, but evidently the construction materials are not up to the job.

Thank you for the suggestions on the plugs. In the meantime, I found a spare set of AVO leads. They seem a bit on the short side but are actually about the same length as these cheap probe leads. They are already terminated with banana plugs and these appear to be of much better quality than the ones I recently purchased. Their resistance tests fine and all they need is a set of probes. I am hoping that these will be Ok?

https://www.ebay.co.uk/itm/273822269...item3fc1143ef0

The suggestions for the banana plugs are still helpful as I also need to make up a couple of sets of PSU to breadboard leads which will also require banana plugs, at least at one end. Although banana plugs are perhaps more convenient, it is also possible to use C connectors at either end. Which are considered to be better suited?

The Philpott · 21st Jan 2022, 1:42 pm

Steel would explain the odd colouration, a new 1p or 2p piece doesn't have to be left outside for long before rust blisters appear in the copper plating. (probably recycled steel which is even worse)
Dave

WaveyDipole · 21st Jan 2022, 1:58 pm

Sorry, just removed the duplicate post, but have attached the missing photos. Not sure what happened.

Alistair D · 21st Jan 2022, 3:18 pm

https://www.warwickts.com/8/Home

I have recommended this company before on here. I have no association with them other than as a satisfied customer.

They do have unshrouded 4mm plugs also a good range of cables.

Al

Diabolical Artificer · 21st Jan 2022, 8:56 pm

I can let you have a couple of meters of very good quality cable in red & black, NOS RS. It's very fine (76 strands? ) copper multi strand with thick flexible outer insulation, not silicon but similar. I've tested it at 1000v + and it passes.

I use these 4mm banana plugs - https://uk.farnell.com/deltron-compo...banana%20plugs good tight fit , good price, if the spring loosens they're easy to re-set unlike others, easy to use and re-use - solder cups not fiddly grub screws, I see Lucian also recommends them. The Hirschmann ones have a really tight plastic outer that gets tighter as they get older. The ones with grub screws poking out the plastic outer are lethal, you can get a shock. The Deltron ones are the best I've found after trying quite a few over the years.

Drop me a PM if interested in the cable. Andy.

wireman · 22nd Jan 2022, 10:57 am

Bringing up a point made earlier. The threshold for free shipping is not too bad. Of the large component suppliers RS have a low threshold for free delivery. I keep a list of items that I want to get more of (one day but not now) and use this to add to any purchase to get up to the free delivery threshold. For Amazon that tends to be batteries.

Considering how fast some of these suppliers deliver and from orders late in the day I'm quite happy with the paid and free options and sometimes choose supplier based on this.

Main problem I have with CPC/RS/Farnell is that there is far too much choice and I often can't decide what to purchase but at least suppliers like these have a lot of product information, unlike ebay/Amazon sellers.

Refugee · 22nd Jan 2022, 12:12 pm

From the link in post #6 also order a roll of black as well and a few plugs and probes and shipping becomes free.
You then get the materials to make 25 1M pairs of leads.

ChristianFletcher · 22nd Jan 2022, 2:05 pm

Not sure if the problems being a bit overstated. I have been buying various cheap test leads from Amazon for quite a while now. I have only really been let down once when I bought some Crocodile Clips jumper cables. The clips were badly crimped with no solder and the wire was very thin. So if you stay away from the very cheap end of the market your likely to be ok. I recently did a review on some cheap kaiweets test leads and was actually very supprised how good they were for the very low cost. I would obviously prefer pomona test leads but you have to factor in how tight I am!

My Test lead review: https://youtu.be/EmZs4L5mrsQ

Herald1360 · 22nd Jan 2022, 10:42 pm

Quote:

Originally Posted by WaveyDipole

.....

The suggestions for the banana plugs are still helpful as I also need to make up a couple of sets of PSU to breadboard leads which will also require banana plugs, at least at one end. Although banana plugs are perhaps more convenient, it is also possible to use C connectors at either end. Which are considered to be better suited?

C connectors? How would they help? (Pic below)

WaveyDipole · 23rd Jan 2022, 2:32 pm

Sorry, I am probably using the wrong terminology, but its the only way I could describe them. They are 'C' shaped, flat and fit around the terminal posts of old AVO meters. They are clamped down rather then plugged in to the banana socket.

Simon Gittins · 23rd Jan 2022, 3:48 pm

Spade connectors. There's another thread about AVO leads that mentions them:
https://www.vintage-radio.net/forum/...d.php?t=110367

Alistair D · 23rd Jan 2022, 4:30 pm

Sorry for taking this thread off topic.

I have a set spade type Avo leads and an Avo that that needs them. The rubber covering on the cables is completely shot and is no longer safe to use.

Since replacements are scarce and likely to be in a similar state, has anyone investigated whether the originals can be re-rubbered?

Al

20th Jan 2022, 7:10 pm	#1
WaveyDipole Nonode Join Date: Mar 2013 Location: Leicester, UK Posts: 2,532	Cheap probe leads and banana plugs Does anyone know what metal is used for the wires in cheap probe leads? I recently purchased a cheap set partly because I needed to cut the ends off and replace them with banana plugs to fit my AVO. The wire inside the insulation was thinner than might be imagined from looking at the leads and although the metal it looks superficially like copper, it has a tarnished and dull appearance. If you scrape it or clean it, the bare wire has a rather antique colour and doesn't have the usual bright shine of 'proper' copper wire. What is it made of? Since I purchased cheap it is perhaps no surprise that the overall resistance of the probe leads adds about 2.2ohms rather than the more typical 0.3 ohms. Then there are the banana plugs. Does anyone sell decent ones these days? Ok, I know that Farnell, CPC and the likes probably do, but unless I place an order to a minimum value the postage cost tends to be rather prohibitive. They used to have quality mouldings and a well machined solid split pins that fit snugly into the moulding and the intended socket. The modern ones tend to be hollow, spring loaded and rather loose and wobbly for most part and with poorly machined threads for the clamping screws to boot. Alternatively, can one still get probe leads without the shrouds? I have not been able to find any. Is this because health and safety prohibit that these days?

20th Jan 2022, 7:54 pm	#3
dodgy-dxer Heptode Join Date: Mar 2008 Location: Newmarket, Suffolk, UK. Posts: 612	Re: Cheap probe leads and banana plugs https://www.cricklewoodelectronics.c...ckets-4mm.html

20th Jan 2022, 9:53 pm	#4
Lucien Nunes Rest in Peace Join Date: Apr 2008 Location: London, UK. Posts: 2,508	Re: Cheap probe leads and banana plugs I have made AVO compatible probe leads by simply cutting the shrouds off normal ones with a Stanley knife. Your dull-looking wireh might be copper-clad aluminium, hence its very high resistance. If you sand it rather than scrape it you can get the Al to show through the Cu easier. Or possibly it's impure copper i.e. not electrical grade. Either way it's a bad material for test leads. There are four main kinds of 4mm plug contact: Bunch pin, Single leaf or wire spring. Lantern contact and split pin. Of these, I find the lantern the most troublesome, not least because there are two contact interfaces in series: pin to lantern and lantern to socket. What often happens is that the lantern makes good contact with the socket but rattles about on its own support pin. I actually have some new UK-sourced test leads with this problem that I need to return, OTOH I have some direct-from-China copies of Hirschmann leads with large CSA copper cores and good, tight lantern plugs. The cross-hole Hirschmann connectors linked above are good and highly rated. There is a low-cost copy by Farnell own-brand Multicomp that seems to work well: https://cpc.farnell.com/multicomp/a-...ack/dp/CN15642 I still quite like the basic Deltron single-spring type. They only make two points of contact with the socket but two good ones are better than a bunch of bad ones. If the plug is tight you know that the pin itself is pressed firmly against the socket wall. And the indirect cable entry and termination is reliable. https://cpc.farnell.com/deltron-encl...ite/dp/CN15656

20th Jan 2022, 10:51 pm	#5
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,104	Re: Cheap probe leads and banana plugs Quick tests for thin wire suspected of being copper plated aluminium- if strands are manually bent they tend to spring back, and subject to a flame they disintegrate. Dave Last edited by Cobaltblue; 21st Jan 2022 at 10:02 am. Reason: Swapped copper and aluminium as requested by OP

21st Jan 2022, 11:01 am	#7
eddie_ce Hexode Join Date: Aug 2010 Location: nr. Hannover, Germany Posts: 372	Re: Cheap probe leads and banana plugs As in post #2 I tend to make up my own leads using very finely stranded, highly flexible silicon coated wire and Hirschmann plugs. I tend to solder these on to the cable rather than use the grub screws available on some versions as I have found that these can come loose with time. __________________ Eddie BVWS Member. Friend of the BVWTM

20th Jan 2022, 7:48 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,995	Re: Cheap probe leads and banana plugs I make-up my own leads using the likes of https://uk.farnell.com/belling-lee/l...-3mm/dp/317100 or the Hirschmann versions https://uk.rs-online.com/web/p/banan...ectors/1902684 and their red equivalents, fitted to silicone-jacketed braid-core ultra-flexy cable.The results are good - I use them to do ad-hoc patching between various HF antennas and their tuners - squirting a couple of hundred Watts of RF on 3.5MHz and they have never melted,. __________________ I'm the Operator of my Pocket Calculator. -Kraftwerk.

21st Jan 2022, 12:41 am	#6
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Cheap probe leads and banana plugs Those cheap leads are more likely to be copper plated steel. It is not worth buying leads to chop up for the wire. You can get a whole reel of real test probe wire for £20. It is 50 strand. https://uk.rs-online.com/web/p/test-lead-wire/2101261

21st Jan 2022, 11:58 am	#8
ChristianFletcher Heptode Join Date: Dec 2003 Location: South Yorkshire, UK. Posts: 900	Re: Cheap probe leads and banana plugs Not on test leads but I have encountered the copper plated steel in cheap gear from china very frequently. __________________ Every Silver Lining Has Its Cloud https://youtube.com/channel/UCvBpiuUUnErJlNBm6DWb3Ww

21st Jan 2022, 1:21 pm	#9
WaveyDipole Nonode Join Date: Mar 2013 Location: Leicester, UK Posts: 2,532	Re: Cheap probe leads and banana plugs Thank you for the replies. I have attached a photo of the end of the wire in question. You can see how dark it is before cleaning near the insulation. I have seen very old wire look like this, but not brand new which is one reason why I asked. Copper plated steel perhaps makes more sense. I suspect that aluminium would have been more fragile. In any case, readings made with the probes also appear to be unstable and fluctuating so they are going in the bin. Their appearance looked the part, but evidently the construction materials are not up to the job. Thank you for the suggestions on the plugs. In the meantime, I found a spare set of AVO leads. They seem a bit on the short side but are actually about the same length as these cheap probe leads. They are already terminated with banana plugs and these appear to be of much better quality than the ones I recently purchased. Their resistance tests fine and all they need is a set of probes. I am hoping that these will be Ok? https://www.ebay.co.uk/itm/273822269...item3fc1143ef0 The suggestions for the banana plugs are still helpful as I also need to make up a couple of sets of PSU to breadboard leads which will also require banana plugs, at least at one end. Although banana plugs are perhaps more convenient, it is also possible to use C connectors at either end. Which are considered to be better suited? Last edited by WaveyDipole; 21st Jan 2022 at 1:41 pm.

21st Jan 2022, 1:42 pm	#10
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,104	Re: Cheap probe leads and banana plugs Steel would explain the odd colouration, a new 1p or 2p piece doesn't have to be left outside for long before rust blisters appear in the copper plating. (probably recycled steel which is even worse) Dave

21st Jan 2022, 1:58 pm	#11
WaveyDipole Nonode Join Date: Mar 2013 Location: Leicester, UK Posts: 2,532	Re: Cheap probe leads and banana plugs Sorry, just removed the duplicate post, but have attached the missing photos. Not sure what happened. Attached Thumbnails Last edited by WaveyDipole; 21st Jan 2022 at 2:20 pm.

21st Jan 2022, 3:18 pm	#12
Alistair D Nonode Join Date: Jan 2010 Location: Edinburgh, UK. Posts: 2,008	Re: Cheap probe leads and banana plugs https://www.warwickts.com/8/Home I have recommended this company before on here. I have no association with them other than as a satisfied customer. They do have unshrouded 4mm plugs also a good range of cables. Al __________________ I won't tell you how I discovered that.

21st Jan 2022, 8:56 pm	#13
Diabolical Artificer Dekatron Join Date: Jul 2009 Location: Sleaford, Lincs. UK. Posts: 7,657	Re: Cheap probe leads and banana plugs I can let you have a couple of meters of very good quality cable in red & black, NOS RS. It's very fine (76 strands? ) copper multi strand with thick flexible outer insulation, not silicon but similar. I've tested it at 1000v + and it passes. I use these 4mm banana plugs - https://uk.farnell.com/deltron-compo...banana%20plugs good tight fit , good price, if the spring loosens they're easy to re-set unlike others, easy to use and re-use - solder cups not fiddly grub screws, I see Lucian also recommends them. The Hirschmann ones have a really tight plastic outer that gets tighter as they get older. The ones with grub screws poking out the plastic outer are lethal, you can get a shock. The Deltron ones are the best I've found after trying quite a few over the years. Drop me a PM if interested in the cable. Andy. __________________ Curiosity hasn't killed this cat...so far.

22nd Jan 2022, 10:57 am	#14
wireman Heptode Join Date: Feb 2021 Location: Edinburgh, Scotland, UK. Posts: 528	Re: Cheap probe leads and banana plugs Bringing up a point made earlier. The threshold for free shipping is not too bad. Of the large component suppliers RS have a low threshold for free delivery. I keep a list of items that I want to get more of (one day but not now) and use this to add to any purchase to get up to the free delivery threshold. For Amazon that tends to be batteries. Considering how fast some of these suppliers deliver and from orders late in the day I'm quite happy with the paid and free options and sometimes choose supplier based on this. Main problem I have with CPC/RS/Farnell is that there is far too much choice and I often can't decide what to purchase but at least suppliers like these have a lot of product information, unlike ebay/Amazon sellers.

22nd Jan 2022, 12:12 pm	#15
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Cheap probe leads and banana plugs From the link in post #6 also order a roll of black as well and a few plugs and probes and shipping becomes free. You then get the materials to make 25 1M pairs of leads.

22nd Jan 2022, 2:05 pm	#16
ChristianFletcher Heptode Join Date: Dec 2003 Location: South Yorkshire, UK. Posts: 900	Re: Cheap probe leads and banana plugs Not sure if the problems being a bit overstated. I have been buying various cheap test leads from Amazon for quite a while now. I have only really been let down once when I bought some Crocodile Clips jumper cables. The clips were badly crimped with no solder and the wire was very thin. So if you stay away from the very cheap end of the market your likely to be ok. I recently did a review on some cheap kaiweets test leads and was actually very supprised how good they were for the very low cost. I would obviously prefer pomona test leads but you have to factor in how tight I am! My Test lead review: https://youtu.be/EmZs4L5mrsQ __________________ Every Silver Lining Has Its Cloud https://youtube.com/channel/UCvBpiuUUnErJlNBm6DWb3Ww

23rd Jan 2022, 2:32 pm	#18
WaveyDipole Nonode Join Date: Mar 2013 Location: Leicester, UK Posts: 2,532	Re: Cheap probe leads and banana plugs Sorry, I am probably using the wrong terminology, but its the only way I could describe them. They are 'C' shaped, flat and fit around the terminal posts of old AVO meters. They are clamped down rather then plugged in to the banana socket.

23rd Jan 2022, 3:48 pm	#19
Simon Gittins Heptode Join Date: Jan 2006 Location: Cornwall, UK. Posts: 505	Re: Cheap probe leads and banana plugs Spade connectors. There's another thread about AVO leads that mentions them: https://www.vintage-radio.net/forum/...d.php?t=110367

23rd Jan 2022, 4:30 pm	#20
Alistair D Nonode Join Date: Jan 2010 Location: Edinburgh, UK. Posts: 2,008	Re: Cheap probe leads and banana plugs Sorry for taking this thread off topic. I have a set spade type Avo leads and an Avo that that needs them. The rubber covering on the cables is completely shot and is no longer safe to use. Since replacements are scarce and likely to be in a similar state, has anyone investigated whether the originals can be re-rubbered? Al __________________ I won't tell you how I discovered that.