Sub Woofer RCA Jack Issues

[Trev]

Hey fellas. I'm sorry for the shockingly newbie post, but I'd rather knowledge than pride.

I've gone through two subs now where the RCA jacks are giving me no signal. If I connect the cable half way onto the jack, I can get intermittent output... which leads me to believe it's not my AVR. Is there a thread already existing here about repairing RCA jacks in subs? Wasn't able to find one.

Or alternatively... is it possible a better quality cable would solve my issue? I've tried three different ones I've had... so it's hard to think it was the cable... unless there's a slightly over-sized one that fits more snug?

I appreciate any help I can get

 

[Irvrobinson]

The cable connector on the sub side might be weak. Have you tried reversing the cable?

 

[markw]

this reminds me of a blonde joke.

A blonde walks into the coctors office and says "Doc, I hurt all over."

Doc says "Show me"

Blonde takes her finger and pokes her arm and says "It hurts here."

She pokes her thigh and says "It hurts here."

She then pokes her head and says "It hurts here, too."

Tthis goes on for about ten minutes and you don't wannna know all the places she poked herself. She says, Well Doc, what do you think?"

Doc says "You're finger's broken.

Replace the cable.

 

[j_garcia]

Which subs are we talking about?

If you had the same problem with two different subs, I'd me more likely to suspect the receiver or cable. It may not be that the cable isn't making contact with the sub, it could be just a defective cable, so the FIRST thing to swap is the cable. Does your receiver have other preamp outputs? If so, set the mains to large and try one of those outputs.

 

[Trev]

...well after going through 3 different cables I have... I just didn't expect to get different results from trying more of the same. Only other thing I can think of is to go out and pick up a really high quality cable.

Model looks almost exactly like a Technics SB-W33, but with Left Right speaker wire options and Left Right RCA connectors. I'm at work at the moment, and I don't recall the exact model off the top of my head.

Sorry, edit: The last sub before IT, was a Polk Audio RM6750's. Would love to be able to flash nicer gear, ...but life happens. My budget it shot. You can see why I've maybe been quick to jump on the belief that the Jacks in the Sub have been the trouble.

 

[j_garcia]

A really expensive cable won't solve the issue. If you've already tried different cables, it is the receiver.

 

[Trev]

A really expensive cable won't solve the issue. If you've already tried different cables, it is the receiver.

...ugh, that would kill me if it were my receiver. Strange though that it would be my receiver if the signal to the sub seems to be dependent on the angle and way my rca is connected to the sub no?

Is it common for a receiver to give up on a sub connection? ...I guess I'm sort of due for a replacement AVR.

 

[slipperybidness]

...ugh, that would kill me if it were my receiver. Strange though that it would be my receiver if the signal to the sub seems to be dependent on the angle and way my rca is connected to the sub no?

Is it common for a receiver to give up on a sub connection? ...I guess I'm sort of due for a replacement AVR.

Did it ever work or is this a new problem? Maybe a config issue?

Try the suggestion of setting main L/R to large and use the L/R pre-outs. If problem goes away then it was something on the LFE channel.

And, is this a music problem or a movie problem, or both. Maybe there is no LFE signal sent on that reciever on music?

Are you using shielded cables? If sub has L/R RCA inputs, maybe try a splitter from the reciever LFE to connect to both RCAs on the sub.

 

[Trev]

Did it ever work or is this a new problem? Maybe a config issue?

Try the suggestion of setting main L/R to large and use the L/R pre-outs. If problem goes away then it was something on the LFE channel.

And, is this a music problem or a movie problem, or both. Maybe there is no LFE signal sent on that reciever on music?

Are you using shielded cables? If sub has L/R RCA inputs, maybe try a splitter from the reciever LFE to connect to both RCAs on the sub.

Yeah, I was just leaning toward trying the splitter. Definitely not a source issue. I run optical from my HTPC to the AVR, and it picks up DTS, Dolby, and different protocols without issue. It doesn't trip out and reconfigure.

Will give some of these options a shot as soon as I get back home. Cables are just your standard light rubber protection. None of that 'Monster' shielding stuff. I used to run the same cable I use from my Mixer to my PC for recording for SPDIF with no issues. :/

 

[j_garcia]

Did it ever work or is this a new problem? Maybe a config issue?

Try the suggestion of setting main L/R to large and use the L/R pre-outs. If problem goes away then it was something on the LFE channel.

And, is this a music problem or a movie problem, or both. Maybe there is no LFE signal sent on that reciever on music?

Are you using shielded cables? If sub has L/R RCA inputs, maybe try a splitter from the reciever LFE to connect to both RCAs on the sub.

It IS possible that this receiver has a low preamp output voltage, but "wiggling" the connector would not seem to fit that which would be a reason to use a Y splitter, that's why I suggested trying different preamp outs to see if they gave the same results.

I wouldn't say this is common, but it does happen. The jack could have loosened over time or had a bad solder joint on the board on the inside of the receiver. If you are handy with electronics, you might be able to open it up and take a look at it and possibly even repair it. Frequent connecting/disconnecting this connection is a likely cause, if you are saying you do this even semi-frequently.

Shielding isn't likely to make any difference either.

 

[markw]

I've had several subs and have never had an RCA jack go bad. I can't think of anyone who has ever had that happen.

The odds of you having TWO go bad is astronomical.

 

[j_garcia]

I've had several subs and have never had an RCA jack go bad. I can't think of anyone who has ever had that happen.

The odds of you having TWO go bad is astronomical.

Agreed. If it were two of the same sub then I'd say it was possible, but two different subs; highly unlikely that both would have exactly the same problem. I have owned approximately 10 different subs and have not had that issue with any of them. I have had RCA jacks come loose on one or two older DVD players though.

 

[slipperybidness]

It IS possible that this receiver has a low preamp output voltage, but "wiggling" the connector would not seem to fit that which would be a reason to use a Y splitter, that's why I suggested trying different preamp outs to see if they gave the same results.

I wouldn't say this is common, but it does happen. The jack could have loosened over time or had a bad solder joint on the board on the inside of the receiver. If you are handy with electronics, you might be able to open it up and take a look at it and possibly even repair it. Frequent connecting/disconnecting this connection is a likely cause, if you are saying you do this even semi-frequently.

Shielding isn't likely to make any difference either.

Some subs that have L/R inputs will tell you to use both (even if just with a splitter) inputs to get the sub to operate correctly. That's why I mentioned it.

Probably not a shielding issue, but figured I would throw that out their.

 

[slipperybidness]

You didn't answer what may be a key question. Same thing with movies and music, or just on music?

Try the L/R pre-outs if you have them and set speakers to large.

 

[KEW]

So, we have:
Three cables would suggest not the cable!
Two subs would suggest not the sub!
Intermittent connection when wiggling the cable suggests it is either the cable or sub!

Somewhere in here you are defying normal probability which likely means something else is at play.
Pure speculation, of course, but it sounds like something may be happening to cause a failure.
Do you have a situation where stress is put on the cable connection at the sub? Maybe you slide it against the wall so the cable is cocking the RCA plug? A cat that likes to lay back there (on the cord) to soak up heat off the amp? Etc?

 

[Trev]

So, we have:
Three cables would suggest not the cable!
Two subs would suggest not the sub!
Intermittent connection when wiggling the cable suggests it is either the cable or sub!

Somewhere in here you are defying normal probability which likely means something else is at play.
Pure speculation, of course, but it sounds like something may be happening to cause a failure.
Do you have a situation where stress is put on the cable connection at the sub? Maybe you slide it against the wall so the cable is cocking the RCA plug? A cat that likes to lay back there (on the cord) to soak up heat off the amp? Etc?

No, I've checked all that. I'd quote all you guys and reply properly, but there've been such an awesome number of replies that it's a bit much to reply to each individually.

I'm an IT guy, and I repair guitars and guitar electronics on the side. I wouldn't doubt that no sub should have it's jacks damaged or loose... that it's highly improbable... but both subs have been purchased second hand, and both had been very old. The Center channel to the Polk set I'd had... had the speaker housing smashed to bits pretty much. Before I started shopping into 5.1 setups, I'd just been using a decent stereo setup. It's expensive to get into proper setups, unless you happen by a sweet tax return or something and can swing the investment. Hopefully soon enough that'd be a possibility for me, but meantime... I've had to work with what I got.

I'm definitely interested in trying the Y Connector and another new cable. I'm just up in Canada and need to find a place that isn't going to charge me $16 each piece. Ideally I'd order off of monoprice, but I'm going to see what I can find in store so as not to burn up all of the help you guys have been offering me.

 

[Trev]

You didn't answer what may be a key question. Same thing with movies and music, or just on music?

Try the L/R pre-outs if you have them and set speakers to large.

Same thing with both movies and music. I re-installed my audio drivers as well. If I stand there holding the connection to the sub at the right angle... I get the clear thumps that should be coming out of it without it cutting in and out.

Trouble is when I let it go or even try to pivot it in a way that the cable won't move... well it's just silly and futile. The sub thumps hard and the cable loses position within 5 minutes (as it's not connected all the way on properly - as when it's on properly i get no signal).

It's just strange to figure that my multiple RCA's are giving me grief... when they work just fine with other devices :/. Will update again as soon as I get those parts in.

 

[Trev]

Face... palm...

Went and picked up new cables and Y connector to cover all bases.

Neither was the problem... but I did find it. Completely freaking warped.

Panasonic SB-AS40. (Back viewable on page 4 'Operation': http://service.us.panasonic.com/OPERMANPDF/SBAS40.PDF )

After messing with the new cables for 5 minutes, I rocked the phase switch back and forth between 'NOM' and 'REV' and all of a sudden thump thump. Works perfectly fine in either position, so I don't know what the hell the deal was. 30 minutes, hasn't vibrated it's way back to cutting out or whatever the hell it's problem was.

I'm thoroughly confounded as to how that switch had a part to play if it works fine with both settings, but only kicked in when I moved it back and forth a few times.

Tested with the first few minutes of 'Immortals' (2011) DTS. It's good to have a sub again.

Really appreciate all of your advice though, everyone. Really. I feel like a tool for troubling you. Hopefully I can give something back to your community - potentially in the HTPC dept.

Regards,

T.

 

[KEW]

Really appreciate all of your advice though, everyone. Really. I feel like a tool for troubling you.

No worries, we all find it very intriguing to observe...I mean, none of us has ever had such an experience!

I would venture a guess that either dust or corrosion had interrupted the contacts where the phase switch is and flipping it back and forth knocked the debris off, "cleaning" the contacts.
Pressing on the connector probably shifted the contact point slightly to a clean spot.

 

[ACsGreens]

Very Juvenile, Sorry

So I know that this is very juvenile and stupid, but I've been on the site reading quite a lot of tech stuff and the comment "standard light rubber protection" made me laugh. I appreciate that, thank you for the childish laugh you gave me.