• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Is there an Audible / Measurable Difference between RCA and 3.5mm Connection?

Joined
Feb 21, 2021
Messages
40
Likes
10
Newbie here, Sorry if this is the wrong place to ask.

I'm looking into having a simple and clean desktop setup, Small Powered Speakers, Headphones, IEMs, Headphone AMP etc...

I notice most of these things have RCA Input & Output, so I was wondering is there any sound quality / measurable Difference between using RCA and 3.5mm Connection? I found an Adapter that is RCA to 3.5mm Female / Male. I'm curious about this as I think using a single 3.5mm makes things simpler and looks cleaner in a way.

Any insight is much appreciated.
 
Last edited:

Jimbob54

Master Contributor
Forum Donor
Joined
Oct 25, 2019
Messages
8,602
Likes
10,513
Newbie here, Sorry if this is the wrong place to ask.

I'm looking into having a simple and clean desktop setup, Small Powered Speakers, Headphones, IEMs, Headphone AMP etc...

I notice most of these things have RCA Input & Output, so I was wondering is there any sound quality / measurable Difference between RCA and 3.5mm Connection? I found an Adapter that is RCA to 3.5mm Female / Male. I'm curious about this as I think using a single 3.5mm makes things simpler and looks cleaner in a way.

Any insight is much appreciated.

If there is, one of them hasnt been wired up correctly. I would buy the kit you want then make the connections work. But I'm curious - RCA tends to be between fixed boxes, 3.5mm tends to be boxes to transducers (or vice versa) unless you are talking portable devices .

When you say "these things" what components are you talking about? A DAC will have digital inputs and RCA outputs. An amp will have RCA inputs, speaker and/ or headphone outputs and maybe RCA outputs for pre amp (or pass thru) duties to other amps / powered speakers.
 

mhardy6647

Master Contributor
Joined
Dec 12, 2019
Messages
5,596
Likes
11,245
When you say "these things" what components are you talking about? A DAC will have digital inputs and RCA outputs. An amp will have RCA inputs, speaker and/ or headphone outputs and maybe RCA outputs for pre amp (or pass thru) duties to other amps / powered speakers.
FWIW... Cheaper components (and some not so much cheaper, but "lifestyle oriented" components :) ) often seem to offer 3.5 mm stereo inputs for analog, line level sources.

Here's a not-at-all randomly chosen example:
1623163440718.png


https://www.parts-express.com/FX-Au...Optical-Coaxial-with-Headphone-Output-230-266

Horses for courses, you know?
 

fieldcar

Addicted to Fun and Learning
Forum Donor
Joined
Sep 27, 2019
Messages
503
Likes
720
One thing that many people neglected to mention is that if this 3.5mm jack is from your motherboard or laptop, it may be a useless distorted and noisy mess with a very audible noise floor. I run the $9 apple dongle DAC at work to drive my headphones on my windows laptop, but it can easily be used as 3.5mm to RCA for a headphone amp or speakers. Just know that a long 3.5mm run beside monitors and other noisy components could cause interference with your signal. It's best to run a usc-c extension, then the apple dongle dac, and a very short 3.5mm to RCA adapter into your headphone amp or speakers.
 

Jimbob54

Master Contributor
Forum Donor
Joined
Oct 25, 2019
Messages
8,602
Likes
10,513
FWIW... Cheaper components (and some not so much cheaper, but "lifestyle oriented" components :) ) often seem to offer 3.5 mm stereo inputs for analog, line level sources.

Here's a not-at-all randomly chosen example:
View attachment 134516

https://www.parts-express.com/FX-Au...Optical-Coaxial-with-Headphone-Output-230-266

Horses for courses, you know?
Yup. What I'm trying to understand from the OP is what is he looking to acquire and for what use case. A £5 dac dongle isn't worse than a £300 desktop dac because of its 3.5mm. It may well be worse performing, but the connection isn't the way to tell (as we know from the Apple dongle etc). It's a design /cost /engineering decision
 

mononoaware

Addicted to Fun and Learning
Joined
Apr 6, 2021
Messages
813
Likes
637
3.5mm in my opinion is the worst of connection types.
They age quickly, resulting in bad contact causing the connection to produce bad audio signal which can damage your equipment.

Recently had the silly idea of connecting Walkman 3.5mm output to an old Sony AV Amplifier using 3.5mm to RCA cable.
Just picking up the Walkman resulted in loud noise and distortion audible from the speakers, which engaged the Sony amplifier’s “protection mode” to prevent damage to Amplifier+Speakers.
(My understanding is certain Sony AV Amplifiers are one of very few which have such a protection mode system)

A proper power cycle (cut wall-socket power, wait 1 minute, restore power) of Sony AV resolved the “protection mode” problem (one speaker consistently stopped signal).


I have had enough of 3.5mm and will avoid using it to prevent permanent damage to equipment. The only suitable use I see for 3.5mm is with “portable audio” such as headphones/IEM’s.
Or in a special case where the 3.5mm plug is permanently inserted into device (current desktop setup is this way with Sabaj DA3 > Powered speakers).

PS: I can recall many times a long time ago when 3.5mm connection produced noise & distortion just by itself, applying force/twisting the connection reduced the noise, but now being more experienced I believe there was still low-levels of noise in the signal even after fixing by twisting the connection, due to bad contact.
 
Last edited:

Soniclife

Major Contributor
Forum Donor
Joined
Apr 13, 2017
Messages
4,137
Likes
4,822
Location
UK
What I'm trying to understand from the OP is what is he looking to acquire and for what use case
Not speaking for the OP, but I use it between my CCA and atom amp, because the CCA comes with a very short suitable cable.
 

Soniclife

Major Contributor
Forum Donor
Joined
Apr 13, 2017
Messages
4,137
Likes
4,822
Location
UK
3.5mm in my opinion is the worst of connection types.
They age quickly, resulting in bad contact causing the connection to produce bad audio signal which can damage your equipment.
Is that because the connector is inherently worse, or because it's nearly always used in mobile devices that get a hard life, how are you accounting for selection bias is what I'm asking.
 

mononoaware

Addicted to Fun and Learning
Joined
Apr 6, 2021
Messages
813
Likes
637
how are you accounting for selection bias is what I'm asking.

The cable I used was sitting in storage, just age causes the contact to have some degradation and become unreliable.
The cable was not damaged by “hard life” or “over use” by plugging many times, it was simply worn out by the environment.
I attempted to “clean” the metal contact but afterwards still had some sort of “rough” finish.

Maybe some brands will fair better than others, but I had a seemingly good quality (judged by it’s overall construction) “Sony” brand cable which suffered from the same degradation.

I suspect there is also a flaw in the design, which is sensitive to the position of male 3.5mm in female 3.5mm port. The slightest force on the angle of plug, or even twisting (rotating) of plug can cause (and sometimes reduce) noise and “spikes” in the signal.
I am sure there is variation of “tolerances” between the many plugs & sockets, but my overall experience over many years has been consistent with having “bad contact”.

I am sure you must have experienced it at least once, when something doesn’t sound right, the you “adjust” the 3.5mm connection and everything is fine (bass comes back, distortion disappears etc).

I have found gold (brass) plated 3.5mm plug seems to last longer in terms of degradation from environment.
But I have still experienced the same issues with these brass plated plugs.
 
Last edited:

MakeMineVinyl

Major Contributor
Technical Expert
Joined
Jun 5, 2020
Messages
3,345
Likes
5,257
Location
Santa Fe, NM
RCA jacks will over the long term be more reliable as the contact area is larger. They should work the same as long as there are no connectivity issues.
 

Soniclife

Major Contributor
Forum Donor
Joined
Apr 13, 2017
Messages
4,137
Likes
4,822
Location
UK
The cable I used was sitting in storage, just age causes the contact to have some degradation and become unreliable.
The cable was not damaged by “hard life” or “over use” by plugging many times, it was simply worn out by the environment.
I attempted to “clean” the metal contact but afterwards still had some sort of “rough” finish.

Maybe some brands will fair better than others, but I had a seemingly good quality (judged by it’s overall construction) “Sony” brand cable which suffered from the same degradation.
I don't see how that says anything about the connector, only that in this case it failed. I've have multiple old grunge RCA cables fail in similar ways when old.
 

pma

Major Contributor
Forum Donor
Joined
Feb 23, 2019
Messages
3,011
Likes
6,049
Location
Prague
I repaired for 15 years and have replaced manyyy 3.5mm jacks. They are money makers for service departments and cause some very weird faults sometimes.

Yeah, poor contacts very often, mechanical cable problems in small connectors. I would vote for a good RCA like one may find here
https://www.audiophonics.fr/en/rca-sockets-c-230.html
Not for sonic reason, but for reliability reason. 3.5mm jacks are a nightmare.
 

mononoaware

Addicted to Fun and Learning
Joined
Apr 6, 2021
Messages
813
Likes
637
I don't see how that says anything about the connector, only that in this case it failed. I've have multiple old grunge RCA cables fail in similar ways when old.

I disagree as in my experience most likely it is an issue with the connection itself (not the stress relief, not the cable inside shield etc).

It is most noticeable when using 3.5mm connection to carry signal directly to an amplifier.
When using with portable audio such as headphones/IEM’s etc the issue is much less pronounced, but I have experienced it (most likely 3.5mm socket made with poor tolerance).
 
Last edited:

mhardy6647

Master Contributor
Joined
Dec 12, 2019
Messages
5,596
Likes
11,245
The only real drawback (IMO) to a 3.5 mm TRS (tip/ring/sleeve) connector is that it's stereo. These connectors effectively "multiplex" (I am using the term extremely loosely!) two "hot" and two "ground" ("common" or "return") connections into a single coaxial connector with three different parts. Slight misalignment of poor connections may cause dropout of one or the other channel, e.g.

1623177451043.png


Otherwise, nothing intrinsically wrong with them, I'd opine.
 

pma

Major Contributor
Forum Donor
Joined
Feb 23, 2019
Messages
3,011
Likes
6,049
Location
Prague
I have not met a single 3.5mm jack that would not have contact issues as a link cable, talking about decades of experience. Good for nothing but DC and even then not very reliable.
 

MakeMineVinyl

Major Contributor
Technical Expert
Joined
Jun 5, 2020
Messages
3,345
Likes
5,257
Location
Santa Fe, NM
Having three connections on a plug can work reliably if the plug is designed properly. Professional TT type plugs are used extensively in recording studios and other professional applications with outstanding reliability, but they are larger than 3.5mm and designed specifically for reliability, not cheapness. 1/4" TRS plugs are used widely in pro-music applications and headphones, but these are far less reliable than the TT type plug and its larger cousin of similar design.

3.5mm stereo plugs are available in a captive design in some professional video gear and I have found these to be reliable as well.
 
Last edited:

mononoaware

Addicted to Fun and Learning
Joined
Apr 6, 2021
Messages
813
Likes
637
The only real drawback (IMO) to a 3.5 mm TRS (tip/ring/sleeve) connector is that it's stereo. These connectors effectively "multiplex" (I am using the term extremely loosely!) two "hot" and two "ground" ("common" or "return") connections into a single coaxial connector with three different parts. Slight misalignment of poor connections may cause dropout of one or the other channel, e.g.

View attachment 134542

Otherwise, nothing intrinsically wrong with them, I'd opine.

I suspect it is more an issue with the contacts (in the female) wearing or becoming deformed, or the male plug being “bent” from the factory causing poor contact.
Both I assume is an issue with factory tolerances with which the issues get worse quickly with ageing of the the metal.

I can even recall a time when a brand-new brass-plated plug had issues (either only one channel working or extremely degraded signal) with which the only solution was to “push” the plug in forcefully, twisting (rotate) it had some effect but caused moments of “white noise”.
(Keep in mind when I say “solution” I mean it “sounded right”, if you were to measure it you might notice a degraded signal with horrible noise floor etc)

Apparently 6.35mm (1/4 inch) has none of these issues, which suggests they were built to higher tolerances due to being for “pro” use.
 
Last edited:
Top Bottom