rattling in 12" woofers in V2

rob_b · « **on:** 30 Apr 2013, 02:53 pm »

Hi guys, I'm having a strange issue with rattling or some sort of vibration on my V2's. I think it might be happening with just one of the woofers, but I can't be sure. It doesn't happen at high volume but is recreate-able at a particular frequency. It almost sounds like the gasket is loose but doesn't make sense since it only happens at a particular frequency. Do you guys have any advice on how to troubleshoot this issue? anyplace I can get a pink noise sweep at different frequencies to test?
Thanks in advance.
Rob

Danny Richie · « **Reply #1 on:** 30 Apr 2013, 03:02 pm »

Gently push in on the cones from the center (straight in) and see if the voice coil is rubbing in any way.

Swap the amps from one speaker to the other and see if it follows the speakers or the amp.

rob_b · « **Reply #2 on:** 30 Apr 2013, 06:27 pm »

Danny, with no signal, it doesn't make any audible rubbing noise. When the amp is on and a signal present, I get a faint distortion sound that gets amplified on the top woofer, when I push the cone in on the bottom woofer. This happens on both the left and the right speakers. I did switch out the amps but no change.

I also took recordings with my iphone voice memo app but not sure how to get them to you.
Do you want me to send them to you via email?

MarvinTheMartian · « **Reply #3 on:** 30 Apr 2013, 09:19 pm »

Rob
You did not specify what frequency or signal source.
After you and Danny have determined that it is not a internal driver issue.

I would start with checking the woofer bolts, after a while they need to be reasonably evenly re-torqued down.
Be careful, one slip and you need a new surround. ( don't ask why I use allen key bolts and socket nuts now ).

Next are the cabinet bits and bolts, if the sound is difficult to localize try the old mechanics stethoscope trick,
preferably hold the fat end of a long socket extension or in a pinch a big screwdriver to your temple,
carefully touch the other end to the hard! / solid! / non electrical! points of interest. You would be surprised what you can hear.

Shawn

tg3 · « **Reply #4 on:** 30 Apr 2013, 11:43 pm »

Tinsel lead slap?

Danny Richie · « **Reply #5 on:** 30 Apr 2013, 11:50 pm »

Quote from: rob_b on 30 Apr 2013, 06:27 pm

Danny, with no signal, it doesn't make any audible rubbing noise. When the amp is on and a signal present, I get a faint distortion sound that gets amplified on the top woofer, when I push the cone in on the bottom woofer. This happens on both the left and the right speakers. I did switch out the amps but no change.

So both speakers have this issue?

rob_b · « **Reply #6 on:** 1 May 2013, 11:46 am »

Quote from: Danny Richie on 30 Apr 2013, 11:50 pm

So both speakers have this issue?

Yes it appears so. I have made sure the bolt are tight as well.

nickd · « **Reply #7 on:** 1 May 2013, 05:36 pm »

I would check the servo wiring. A loose connection or crossed wire makes the amp servo system missread the voice coil location and a "clacking" sound can be heard under this condition at moderate output.

I used threaded inserts and machine screws and removed the rubber gaskets to get a nice solid woofer mount. You might inspect for stripped screw holes if you just zipped them into MDF?

Hope you find the gremlin.

rob_b · « **Reply #8 on:** 2 May 2013, 02:16 am »

Ok, a bit more on this issue. I have disconnected all wires except the to the amp from the woofers. With the amp on and no source connected, I can hear an audible hum when my ear is next to the woofers. What interesting is that when I gently push the cone in on the woofers, the buzzing gets louder. This happens on both speakers. I'm not sure if this is related to the distortion I hear when the woofers are activated.
I have created a public folder to get an idea of what I'm hearing. I used a basic voice memo on my iphone to capture it with the mic mere inches to illustrate it happening at very low decibels levels.
Here is the link:

https://skydrive.live.com/redir?resid=42A28017C8C28533!357&authkey=!ABVqzy138mfMhl4

The first one is part of a movie at approx 70db. I turned the volume up just enough to trigger the woofers to cut on.

The second is the low level hum getting amplfied when I press on the woofer. The mic is on the top woofer and i'm pressing (gently) on the bottom one.

What do you guys think?

Danny Richie · « **Reply #9 on:** 2 May 2013, 02:28 am »

Okay, a slight hum would be a ground loop issue with the amp. That can often be killed with a cheater plug or disconnecting the ground wire in your power cable.

I could not play those files you uploaded. So I can't really comment on those.

rob_b · « **Reply #10 on:** 2 May 2013, 02:36 am »

Quote from: Danny Richie on 2 May 2013, 02:28 am

Okay, a slight hum would be a ground loop issue with the amp. That can often be killed with a cheater plug or disconnecting the ground wire in your power cable.

I could not play those files you uploaded. So I can't really comment on those.

Sorry Danny, I converted the files to a regular MP3. You should be able to play them now. I'll try the cheater plug and report back.

rob_b · « **Reply #11 on:** 2 May 2013, 02:11 pm »

Ok, so I put on a cheater and there is no difference. Actually the SA-1 amps only have a 2 prong IEC connector, but I put on a cheater plug just to be sure.
Did anyone get a chance to listen to the files I put up? It almost sound like a shielding or crosstalk electrical issue.

Can anyone direct me to a link to the wiring for the V2 woofers so I can make sure they are wired correctly?
Man, I'm at my wits end here.
TIA

Danny Richie · « **Reply #12 on:** 2 May 2013, 02:17 pm »

I listened to them but it was hard to tell what it really was.

Try hooking the woofers to any power amp and play some bass heavy tracks. Let's run out for sure that it is the SA-1 amp.

I have plenty of those woofers in stock and will take care of you if it is a woofer issue. I'll warranty those for a long time.

The SA-1 amps are past the warranty period, and I have no more of them. So if the problem is the amp then I have another solution for you that will not be too expensive.

rob_b · « **Reply #13 on:** 2 May 2013, 02:52 pm »

Quote from: Danny Richie on 2 May 2013, 02:17 pm

I listened to them but it was hard to tell what it really was.

Try hooking the woofers to any power amp and play some bass heavy tracks. Let's run out for sure that it is the SA-1 amp.

I have plenty of those woofers in stock and will take care of you if it is a woofer issue. I'll warranty those for a long time.

The SA-1 amps are past the warranty period, and I have no more of them. So if the problem is the amp then I have another solution for you that will not be too expensive.

Ok, I hooked up one of them straight to an amp and fed a full signal and no sign of rattling or distortion. Is it possible that I have 2 bad SA-1 amps?

cleestedwood · « **Reply #14 on:** 2 May 2013, 03:06 pm »

sl_1800 had a pair of amps for sale . Last post was March 2 on Trading Post

rob_b · « **Reply #15 on:** 2 May 2013, 08:27 pm »

Quote from: cleestedwood on 2 May 2013, 03:06 pm

sl_1800 had a pair of amps for sale . Last post was March 2 on Trading Post

Thanks, will look into it though I'm afraid of this happening again. Danny, is the below amp from partsexpress any worse than the SA-1?

http://www.parts-express.com/pe/showdetl.cfm?partnumber=301-510

The only issue is the the cutout is different which is a problem.

jparkhur · « **Reply #16 on:** 2 May 2013, 10:17 pm »

A bunch of guys had me build amp boxes for those Jung amps. They are dirt cheap and are a very good replacement for the sa1. I have one set of black amp boxes for one of these. Forget which model. Anyone can have them if they need them. I think it's the 300

rob_b · « **Reply #17 on:** 3 May 2013, 02:31 am »

Quote from: jparkhur on 2 May 2013, 10:17 pm

A bunch of guys had me build amp boxes for those Jung amps. They are dirt cheap and are a very good replacement for the sa1. I have one set of black amp boxes for one of these. Forget which model. Anyone can have them if they need them. I think it's the 300

Man, that would be great if Danny signs off on them. I'll pm you about them.
Thanks.
Rob

Danny Richie · « **Reply #18 on:** 3 May 2013, 03:03 pm »

Yeah, those things will work. They don't have a transform circuit like the SA-1 does, but it does have a boost circiut in the right area.

rob_b · « **Reply #19 on:** 3 May 2013, 03:06 pm »

Quote from: Danny Richie on 3 May 2013, 03:03 pm

Yeah, those things will work. They don't have a transform circuit like the SA-1 does, but it does have a boost circiut in the right area.

Danny, would you suggest going with a used pair of SA-1 or these? Have you have any excessive reports of bad SA-1 amps?