How to Get a good connection to a Regular Amp with RCA plugs

[jamiedolan]

HI;

I have a set of some nice JBL 2500 series speakers hooked to an RCA amp. I have to input to tine RCA with standard RCA / A/V cables. So I have used a 1/8" to RCA cable to make the connection.

I've tried several different cables and don't feel like I am getting that good of a connection. Sometimes I will have to go wiggle the plug a bit to get it to sound right again. I even tried a Apple brand name cable and had the same problems. The Amp sounds fine if I have something like a Ipod connected to it directly with the same type of cable.

I'm wondering if I should buy some type of USB to RCA adaptor so I can connect directly to the amp with that?

I don't need any super high end output, just consistent quality. The computer I have connected to the amp right now, I am coming out of a audio out jack on back, not a headset jack.

Thanks,

Jamie

 

[fireberd]

I'm a guitar amp tech (among other things). Is it the 1/8" stereo plug end that connects to the PC or the RCA plugs? Generally, RCA plugs are trouble free. There are gold plated connectors (both 1/8" stereo and RCA) that will maintain connection a little better, but I've never had a problem with the standard plugs. I also have a recording studio and have RCA connectors that have not been moved or reconnected for months - just standard run of the mill plugs and no problems.

If its the amplifier end that the RCA connections are flakey, don't rule out the RCA connectors in the amp. I have seen some cheap connectors on amps. RCA amplifiers are not "high end" and the connectors in the amp could be the problem.

 

[jamiedolan]

I'm a guitar amp tech (among other things). Is it the 1/8" stereo plug end that connects to the PC or the RCA plugs? Generally, RCA plugs are trouble free. There are gold plated connectors (both 1/8" stereo and RCA) that will maintain connection a little better, but I've never had a problem with the standard plugs. I also have a recording studio and have RCA connectors that have not been moved or reconnected for months - just standard run of the mill plugs and no problems.

If its the amplifier end that the RCA connections are flakey, don't rule out the RCA connectors in the amp. I have seen some cheap connectors on amps. RCA amplifiers are not "high end" and the connectors in the amp could be the problem.

Thanks for responding. The 1/8" plug is on the computer side (female jack on the computer), then I use a cable that converts it to RCA.

It doesn't seem like the RCA cables are flaky at all. It seems to be the 1/8th connection, as that is very prone to noise if I go wiggle that cable around just a little bit.

I recorded a quick video showing my cable setup from the computer to the amp. Note that I've tried, I would say at least 3 different sets of cables here and I end up with noise / click while I'm listing and sometimes it sounds like it just shifts to Mono all of the sudden. If I unplug the 1/8 and plug it back in, it normally gets better again.



Maybe the RCA amp it's self is going bad or the connections are just bad as you suggested. I think my dad might have a mcintosh or maybe a sansui that I could use, then I could pretty much rule out the amp being a problem.

If you think this type of cable setup looks okay, then I will try to get a new amp tomorrow.

Thanks,

Jamie

 

[ICIT2LOL]

James how old is the computer jack plug and lead could be something simple as a lead in the moulding has broken or the computer socket contacts are not making good contact with the jack terminals.

Take a look at the pics in this http://en.wikipedia.org/wiki/Phone_connector_(audio) (lower down you will see the sockets terminals that correspond to the jack plugs terminals.)

 

[fireberd]

Looking at your video, it appears to be a problem at the PC rather than the RCA plugs at the amp.

And, it sounds more like the ground connection than the actual audio connections with the hum you get when you wiggle it or pull it out. The long (or at least looks long) cable run and the extra connections between the two cables could be a source of the grounding problem.

With audio, you need to generally keep the lead length to about 20 ft or less (for no fidelity loss). You should also use one long cable rather than the two cables you have to minimize any possibility of connection problems.

I haven't run across any problems with jacks in the PC, although its a possibility. The problem is the jacks are not field replaceable, in fact in most cases if the jacks are bad then the motherboard will have to be replaced. Considering its a Dell XPS it has a Dell proprietary motherboard so the next best option is to install a separate sound card and use that instead of the Integrated (on the motherboard) audio.

Another option is to use S/PDIF (digital) if the RCA has an S/PDIF input. Most of the Studio XPS systems have S/PDIF digital out. Actually, the S/PDIF Is the preferred method as its all digital and not prone to problems such as you are experiencing.

 

[strollin]

Based on your video I would suspect the headphone/lineout jack on the computer itself first. Does your computer have a front panel headphone jack? If so, try plugging your cable in there and see if it makes any difference. As fireberd said, you should try to shorten the cable run from the computer to the amp. I would also suggest you try to eliminate the adapters that are converting from female RCA to male RCA as stuff like that increases the chance of noise and ground loops. You should be able to find a cable with the 1/8" plug on one end and male RCA plugs on the other end.

 

[jamiedolan]

James how old is the computer jack plug and lead could be something simple as a lead in the moulding has broken or the computer socket contacts are not making good contact with the jack terminals.

Take a look at the pics in this http://en.wikipedia.org/wiki/Phone_connector_(audio) (lower down you will see the sockets terminals that correspond to the jack plugs terminals.)

The computer was custom built about 5 weeks ago. I had my 3.5 year old Dell tower do almost exactly the same thing with the audio and just thought it was the cable.

This is the audio card that is built into the Intel motherboard.

The cables I am currently using I purchased from Amazon about a month ago.

 

[jamiedolan]

Looking at your video, it appears to be a problem at the PC rather than the RCA plugs at the amp.

And, it sounds more like the ground connection than the actual audio connections with the hum you get when you wiggle it or pull it out. The long (or at least looks long) cable run and the extra connections between the two cables could be a source of the grounding problem.

With audio, you need to generally keep the lead length to about 20 ft or less (for no fidelity loss). You should also use one long cable rather than the two cables you have to minimize any possibility of connection problems.

I haven't run across any problems with jacks in the PC, although its a possibility. The problem is the jacks are not field replaceable, in fact in most cases if the jacks are bad then the motherboard will have to be replaced. Considering its a Dell XPS it has a Dell proprietary motherboard so the next best option is to install a separate sound card and use that instead of the Integrated (on the motherboard) audio.

Another option is to use S/PDIF (digital) if the RCA has an S/PDIF input. Most of the Studio XPS systems have S/PDIF digital out. Actually, the S/PDIF Is the preferred method as its all digital and not prone to problems such as you are experiencing.

I actually had the cable plugged into my new computer in the video, which was custom built about 5 weeks ago. It has an Intel 2011 series board in it. I had a very similar problem with the audio when I was plugged into the Dell Studio XPS. Thus I had assumed this was some kind of fundamental problem with the type of cable / connection to RCA that I was using.

I'd have to take it off to measure to be positive, but am almost sure that these cables are each 6 feet long for a total of 12 feet of cable from the computer to the amp.

I'm not familiar with what the S/PDIF digital out is, I will look it up.

I'm going over to my parents in about a half hour and plan to get a different amp from them.

I will have to order a new cable to get one that is solid that reaches to the amp, unless I can figure out a spot for the amp on this side of the room (which I think I might be able to do).

Thank You,

Jamie

 

[jamiedolan]

Based on your video I would suspect the headphone/lineout jack on the computer itself first. Does your computer have a front panel headphone jack? If so, try plugging your cable in there and see if it makes any difference. As fireberd said, you should try to shorten the cable run from the computer to the amp. I would also suggest you try to eliminate the adapters that are converting from female RCA to male RCA as stuff like that increases the chance of noise and ground loops. You should be able to find a cable with the 1/8" plug on one end and male RCA plugs on the other end.

I had some of these same issues on the Dell that I'm having on the new computer now. Now that you mention the second port, I do recall that I tried both the front headphone and the rear speaker port on the dell. I can't recall right now which one worked better, I think it was the rear port, but it still had problems.

It is like interference from something though, because it seems to flake out for no reason with no physical movement.

Once I pick-up the new amp, I will see if I can place it so it is under the computers and I can just use one cable to connect the computer to the amp.

I saw this kind of thing on Amazon; which I was wondering about because it seems like it is a device that makes a digital conversion to RCA: Amazon.com: Behringer UCA202 Audio Interface: Musical Instruments

I will try the other suggestions first, but don't mind buying some kind of adapter / converter if necessary.

Thank You;

Jamie

 

[jamiedolan]

Sorry I've not added my new computer to my profile; This is the board in my new machine: Intel® Desktop Board DX79TO I'm using the built in audio.

"Intel® High Definition Audio (Intel® HD Audio) subsystem in the following configuration:
6-channel (5.1+2 independent multi-streaming) audio subsystem with three analog audio outputs"

 

[fireberd]

The Behringer is for inputting audio, not output.

I've never really run across any problems with audio jacks on PC's. Obviously there can be problems, but very rarely. I don't have any problems with the plugs either. There are gold plated connectors, but unless both the jack and plug are gold it isn't worth the extra cost for just gold plated plugs.

One other possibility is a "ground loop" problem - a difference in electronic potential of the grounds in two devices. One thing to try is "lift" the ground on the amplifier AC power plug (if its a 3 prong plug). You can get an adapter for the AC power plug. We run into ground loop problems (hum) quite frequently with AC powered musical equipment.

As I previously mentioned, if you have S/PDIF (digital) output on the PC and an S/PDIF input on the amplifier consider using this instead of the analog audio connections.

 

[ICIT2LOL]

Hum well I agree with fireberd the likelihood of the board socket being broken or faulty is highly unlikely but it doesn't rule out that one use has dislodged a potential dry joint and that the jack it self was perhaps faulty / weak at manufacture.
As suggested try another lead, and if necessary use an old one with stripped ends to carefully test for continuity in right / left and ground leads (socket to lead end) . .

 

[jamiedolan]

Just an update; I got a new cable from my dad the other night and a new amp. I've only hooked up the cable so far. I've played a fair amount of music the last couple days and it has all sounded perfect.

This is now the 4th new cable I've tried. So I'll give it a little more time before I say for sure that this cable fixed it. If I have more problems, I'm ready to swap out the amp with a different one.

Thanks,
Jamie

 

[ICIT2LOL]

Well done Jamie and just for the record mate always buy good quality leads some of the rubbish that you think is a bargain is really - well rubbish.

Another good thing to do if you are using that jack a lot is to reinforce the lead from the jack to about two inches out with some of that cloth duct tape - doesn't need to look glamorous and in most cases i don't even notice it. Its just there where a lot of flex takes place mate.