Hi, i just wanted to add to the last RCA post, and post some photo's of how the final solder joints should look. The old photo's only comply to class 1, which only meets requirements of funcionality. To meet class 2 or 3 (military standard) you need to meet the requirements of form, fit and function (in my case) for coaxial termination. As RCA plugs are technically not a coaxial terminal, the final result probably wont meet highest standards anyway (mil spec). To get the joints to wet properly, make sure you pre-tin the terminals, the center conductor/s and the braid. Use a large tip (say 3-4mm) and about 340`c and additional RMA flux as necessary, but dont use an agressive one like bakers fluid etc it WILL affect reliability.... So here is a better standard of soldering to work to! comments welcome. And yes, these two would only comply to class 2 (commercial product) as the joints are not quite perfect.



Click to view attachment



Click to view attachment

That is how it should look!

I hate those cheap plastic rcas though but they do the job

Yeah sorry about the plastic rca's, they were in the prototype room at work (in otherwords, free!!) the Coax is millitary spec tho I'm thinking I should have bought some of those anodised alumminium ones but they are about $30 each!

Apparently Canare make some nice ones. They're about as close to true 75ohm RCA's as you will get.
Come as a crimp terminal though, although solder terminals may be available.

good soldering is important - nice job there

P.S. audio RCA isn't 75 ohm

would 75ohm coax overly effect the audio signal?

since it's such low frequency, it doesn't make much difference.

theoretically, you should match the output, input and transmission line impedances... like balanced audio uses 600 ohm, etc.

Yeah, since the audio frequencies are so low (relative to IF/RF), they won't really get affected by the impedence of the cable. That soldering job is very good, but I'd probably close the clamp a bit around the cable to give it 'mechanical anchorage' (my word for the day ), so when it's tugged on, the solder joints aren't put under pressure. Not that it realllllly matters, just I'm being fastidious.

I think you'll find that solder going into the insulation is a process indicator for class 2, and a defect class 3.

But I may be wrong

Also, the insulation being stripped back that far on the centre conductor (mainly on the red plug) would also be a process indicator, or more than likely, a defect.

edit: just went and looked up the standards, yeah, your red RCA is a process indicator for classes 2 and 3, and may even be considered a defect.

it is however acceptable for class 1, the previous thread with the RCA assembly was a defect for all classes, no question about that.

ok cool, so aparently not "class 2" but they do look nice huh

I should post some pics of the RCA splits i made the other day, they were nice. RG315 (i think?) coax, and i bought some proper brass connecters lol after the suggestion to steer clear from plastic.

cheers
James

Does anyone know a site or something where I could learn more about the different classes of cable soldering?

Hmmm the standards are run by IPC, (American?) which looks after the international electronics standards... the books aren't free. Only really work training in if your an electronic tech... I realize now it was a bit pointless talking about what standard RCA's and all that anyway. It's not like it's a very regulated industry anyway, as far as soldering and crimping standards.

But if your interested, the standards follow 3 levels of product quality, which determine the functionality or form (looks) of someone's work. Within each class there is 4 levels of requirements that determine if the work is either Target (best quality), acceptable, process indicator (where quality is low and should be noted) or a defect (where it's so bad it doesn't even work, usually). most peoples soldering is defect haha

The 3 classes are:

Class 1: is general electronic products, or the consumable electronics (like amp's) etc that come out of china, is usually a poorer standard of work. (most electronics fall under this category). Mostly process indicator or defect falls under this category

Class 2: is dedicated service electronics, like communications equipment. Usually acceptable or target quality work.

Class 3: is High performance electronics, like military equipment. all work must pretty much be target quality (no, not the shop) is very reliable stuff usually - but comes with a HEFTY $$$$ tag. (this is the stuff i work with )

Great thread.
Thought I'd contribute. Here are my tips for soldering.

- Clean the work & iron. If you constantly have messy hands from working on your cars, like me, then having contact cleaner, hand cleaner & alcohol type cleaning wipes, is a good idea. Cleaning the copper on a cable, RCA plug, etc before soldering is a good idea too, best done with a spray on contact cleaner, but not overly necessary. But the most important part is keeping the soldering iron tip clean;- clean it each time you pick it up to solder a joint. Wipe it on a wet rag or sponge, this will help the tip keep clean. Listen for that "shhh" sizzle each time this is good indicator that the solderin tip on the iron is ready

- Hold the work still. The key to a good solder joint is to let it set properly and harden, without moving it. So use tools or tape it to something (maybe a piece of scrap wood) so that the plug, cable, lug, etc. can't move whilst your working on it. Then you hands are free to manipulate the soldering iron & the solder. A good joint will be nice and shiny like the ones above . A poor joint will look kinda "frosted" once its hardened. These frosted or hot joints as some people call them help loose voltage!! Not good! So they need to be re-soldered.

- Heat the surface/cable/tag first; then apply the solder in a controlled manner.

- For larger speaker cables, wait for the iron to heat the cable up first. Then apply solder (note on some power cables its best to use crimp lugs. Heating v/big cable could damage the protective outer sheath since so much heat needs to be worked into the cable to solder it.)

Here is a few videos that show how to solder. Its for a printed circuit board (pcb), but the technique is the same. Notice how he pays attention on keeping the soldering iron clean. Practice on scrap bits of cable first, then go onto joining two cables together. Then you can move onto stuff like RCA plugs.
<a href="http://radiojove.gsfc.nasa.gov/telescope/soldering.htm" target="_blank">http://radiojove.gsfc.nasa.gov/telescope/soldering.htm</a>

More great videos!

http://www.solder.net/technical/tips.asp

I hope this helps.