#161321  by Incaroads77
 Wed May 16, 2018 10:35 am
I bought an e120, had a tiny bit of rub. No big deal. Fast forward a couple weeks, it started just cutting out. Strum a chord kinda loud then it comes right back on. It cuts out from things like me setting my phone on top of the cabinet. Or from me knocking the cabinet/walking around it without tiptoeing. (1x12 TRM cab) So i go and buy a k. No rub, re-coned from what i can tell was a factory re-cone kit. Very happy with it. same story as above with the E. Starts randomly cutting out. Play a chord/turn twin off/on and it comes back to life. I play low volume, bedroom setting usually. But i do plan on playing a gig here and there.

So my questions are; Is this just my bad luck? voice coil issue? is it something that would only happen at low volume? as in, If the speakers were really being driven at louder volumes would this be happening? I've now spent nearly 400 bucks on two speakers trying to have a nice simple jerry tone (i'm a broke college student who has no business having a three thousand dollar + rig) So does anyone have any insight on how to fix this? Re-coning? This has been a huge letdown, and i'm thinking that maybe this is just something that comes along with using 30 year old speakers. Maybe someone can provide some insight or a story of their own.

-Vic
 #161323  by Erbis
 Wed May 16, 2018 11:17 am
Sounds like a connection issue or a loose solder joint... possibly a loose wire in the guitar...i would start with the easiest connections and troubleshoot them first... make sure the 1/4 cable from guitar to amp doesn't have a short in it...i have had all these issues at one point or another... everything is vibrating and prone to issues... even a vibrating tube socket wire will cause issues... make sure the wires going to the speakers are connected at the push in sockets well and not making intermittent connections...a loose solder joint inside the preamp could also be causing this... start simple and logically and work your way to harder to diagnose and good luck
Gr8fulCadi liked this
 #161324  by Incaroads77
 Wed May 16, 2018 11:33 am
thanks for the reply

This is something that happens with any amp head i plug the speakers up to. So i've limited the issue to the speakers at this point. Just wondering if anyone else has ever had issues like this with thier JBL's
 #161325  by lovetoboogie
 Wed May 16, 2018 12:01 pm
It does not unfortunately sound like the drivers are the issue... It would be a perfect storm to have say an intermittent voice coil on 2 JBL's... with that said, I suggest working back from the speaker. Check your wiring in your speaker cab. The wire itself(some braided speaker hookup wire can fatigue and fail), the jack(oxidation on the ground sleeve, solder joints at the jack lugs, etc...), the speaker cable you are using could also be suspect so rule that out by using any old good 1/4" cable. Once you have done that you will have to rule out your guitar and/or instrument cable(since you tried different amps). Let us know...
 #161327  by Gr8fulCadi
 Wed May 16, 2018 12:36 pm
I have to agree above, tho we all could be wrong but anytime something is wrong twice or with two items I always investigate elsewhere. If you have the opportunity to put a known working speaker into your cabinet that would help isolate the problem. Or take your JBL to a completely different rig/speaker cab/cables etc.
 #161330  by Erbis
 Wed May 16, 2018 1:51 pm
You might also try the 1/4 cable that comes out of the jack... some cables don't work well with certain jacks, or the little tab inside the jack might not be making great contact with the end of the cable...i have also seen where subtle movements to the cable coming out of the guitar will either cause the wiring to short out or make the cable lose contact with the jack...
 #161332  by Incaroads77
 Wed May 16, 2018 6:23 pm
Thanks everyone for the advice.

I reached out to my local music store today for some advice as well. From what i'm told, there is a better chance that my DSR and my friends bassman both have a cold solder joint/bad connection somewhere and are experiencing similar symptoms, than there being an issue with those jbl's. Makes sense. Setting a phone on a 26 lb. speaker shouldn't cause it to "cut out" lol.
 #161333  by Incaroads77
 Wed May 16, 2018 6:29 pm
Back to the drawing board. All i have are 1m 1/2w carbon comp resistors at the moment. If those aren't suitable for draining filter caps, is there a way to connect a few to make a halfway decent way for draining them? I have a replacement eyelet board on the way as the current one is significantly warped and mummified with dust,. Im just gonna restore this thing. So many connections to inspect and i don't have a osc scope or anything. Nor do i have 300 bucks to give a tech.
 #161334  by Incaroads77
 Wed May 16, 2018 6:31 pm
i already replaced the filter caps and all the white stock caps that were in there and a few others that i was told needed to go. so i do have a little experience. Just don't have the same resistors i was using to drain the fc's
 #161335  by gmchart
 Thu May 17, 2018 7:49 am
No disrespect to the local music store but two amps having the exact same problem is as unlikely as two JBLs with the exact same problem. Does your buddy's amp work in his rig? Slow down, and start at the beginning. Plug a different guitar into your rig, then a different cord. Any effects? Take 'em all out and put 'em back in one at a time (jumper cords...one at a time). I know I sound preachy, but I have never once learned anything the easy way. Bought a replacement amp once when the culprit was a dirty pot on the Delay pedal--squirt of Deoxit and good to go.
 #161341  by PurpleTrails
 Thu May 17, 2018 4:20 pm
That definitely sounds like a bad solder or contact issue. When a voice coil goes that isn't what you're going to be hearing.