RCA Plug to Coaxial Cable: Crimping and Soldering Guide
Attaching an RCA plug to a 75 ohm coaxial cable is the core DIY skill behind digital audio patch cables, antenna feeds and AV wiring. Done wrong, the joint cracks, hums or drops bits under load; done right, it is as good as a factory cable for the life of the run. This guide walks the strip dimensions, the mechanics of crimp versus solder, the testing that proves the joint is clean, and the specific mistakes that cause digital dropouts after a cable looks perfect.
Quick Answer
For a reliable RCA plug to coaxial cable joint: strip about 20 mm of jacket, about 12 mm of shield, expose roughly 15 mm of center conductor, and trim the dielectric so about 2 mm shows. Solder the center conductor to the pin and the shield to the shell for 360-degree contact, or use a proper 75 ohm crimp connector with its dielectric spacer. Verify with a multimeter: pin-to-center closed, pin-to-shell open, and shield fully bonded to the shell. A joint that passes all three tests is a finished joint.
Tools and Parts
The kit is small: a coax stripper (or a sharp knife and steady hand for one-offs), 60/40 rosin-core solder, a fine-tip iron, flux for the shield joint, 75 ohm RCA connectors (solder type for permanence, crimp type for serviceability), and a multimeter. The connector choice drives everything else: solder connectors have open pin and shell for tinned joints; crimp connectors have a barrel the tool compresses onto the shield and a pin the center conductor crimps into. Both must be specified for 75 ohm and include the dielectric spacer – a missing spacer changes the local impedance at the joint and shows up as dropouts on long digital runs.
Crimp vs solder: honest comparison
Solder wins on permanence and shield contact: a tinned 360-degree joint cannot work loose. Crimp wins on serviceability: a failed field joint can be stripped and re-terminated in minutes without an iron. For a permanent digital audio run behind a wall or in a rack, solder. For a test cable, a camera line or anything likely to be reworked, crimp. The dimensions are identical either way.
Step-by-Step Termination
Order matters. One: strip 20 mm of jacket, leaving the braid clean and un-kinked. Two: strip or fold back 12 mm of braid. Three: expose the center conductor so about 15 mm reaches through the connector’s dielectric spacer. Four: trim the dielectric so roughly 2 mm shows past the braid – no more, or the pin can arc to the shell. Five: seat the connector; for solder, tin and flow the center to the pin, then gather the braid and solder it to the shell. Six: cure, inspect under light, and run the three multimeter tests. The companion female-side guide, coax to RCA jack, uses the same dimensions, and the signal spec the joint must preserve is in coaxial RCA.
Testing the Joint
Three measurements, ten seconds each. Continuity: pin to center conductor – should read closed (near zero ohms). Isolation: pin to shell – should read open (infinite); a closed reading means a braid strand or solder bridge shorts the signal to ground, the classic cause of a dead line. Shield bond: center of braid to shell – should read closed, proving 360-degree contact. On a digital cable, add a live test: run S/PDIF through the joint and watch the receiver’s format indicator for a minute or two of playback; a joint that passes the meter but fails the live test has an intermittent that flexing exposes, and the fix is re-terminating, not dressing the cable.
Mistakes That Cause Digital Dropouts
Four failure patterns cover almost every bad joint. Braid-to-pin contact: a single strand across the dielectric causes crackle that varies with cable movement. Crushed dielectric: over-tightening a crimp deforms the spacer, kinking the impedance at the joint; the symptom is dropouts that worsen as the run lengthens. Cold solder: a shiny joint is a good joint; a dull, grainy one is a mechanical connection that fails under thermal cycling. Over-strip: center conductor exposed past the spacer arcs in humidity and shorts at the wrong moment. Each is preventable by following the dimensions and running the meter tests before the cable leaves the bench.
RCA Plug Termination Dimensions (75 Ohm Coax)
| Step | Dimension | Detail |
|---|---|---|
| Jacket strip | ~20 mm | Expose braid, keep braid un-kinked |
| Shield exposure | ~12 mm | Full shell contact, no pin crowding |
| Center conductor | ~15 mm through spacer | Seated in pin, no float |
| Dielectric exposure | ~2 mm max | No arc, stable local impedance |
| Pin-to-shell test | Open (infinite) | Closed = short, re-terminate |
Real-World Applications
The RCA-to-coax termination skill shows up in specific builds: a DIY digital audio cable where 1505A-class coax is terminated with orange RCA plugs for a home theater run; a TV antenna feed where the attic drop ends in a custom-length run to the TV; an in-wall patch where a builder’s cable must meet an RCA plate at the device end; a repair shop job replacing a failed factory crimp on a customer’s digital cable; a rack build where every 75 ohm run gets matched-length custom cables; and a camera line where BNC-to-RCA pigtails are crimped in the field. In each case the same dimensions and the same three meter tests apply – the skill is transferable across every coaxial install in the house.
Related Guides
Frequently Asked Questions
Do I need special solder for a coaxial RCA plug?
No – standard 60/40 rosin-core solder works. Flux helps the braid-to-shell joint flow, and a fine tip keeps the joint small enough that heat does not cook the dielectric.
Why does my DIY digital coax cable drop out during playback?
An intermittent: a braid strand brushing the pin, or a shell contact that only closes at one bend angle. Flex the cable near the joint while monitoring the receiver; re-terminate with the shield fully bonded and the pin isolated.
Can I reuse a broken RCA plug by twisting the wires in?
No. Use a new 75 ohm-rated connector. A twist joint has no shield contact, no dielectric spacing and no mechanical retention – it fails electrically and mechanically, usually within a week of normal use.
Crimp or solder for digital audio?
Solder for permanence – a tinned 360-degree shield joint is the most failure-resistant option. Crimp for anything that may need rework in the field. Both work at spec if the dimensions and tests are followed.