OBEL issues...need suggestions.

OBEL issues...need suggestions.

Postby NSP » Fri Nov 25, 2011 9:07 am

My apologies for double posting as this is building on my PRS wiring post, but thought I'd start a new thread.

Hey All,

Now I have everything all wired up according to the diagram below but I have a strange issue I haven't been able to figure out. When I have the DPDT switch in bypass everything works as I would expect and sounds good, with no effects of course. When I engage the loop all of my pedals behave very strange. e.g. my delay pedal sounds as though I have all the knobs maxed out with intense delay and decay, when in fact the dials are set to minimal effect. When I hit the Qtron it screeches as if the signal is way to hot? All of my effects are behaving in a weird way.

I built my own junction box as well according to the other diagram below, but now looking at it again the only difference is I ran two ground wires from the stereo jack with one going to the send and one going to the return instead of daisy chaining as the image shows. Any chance this could cause a problem? I just noticed this so I haven't had a chance to go rewire it yet to see.

Any thoughts or suggestions would be greatly appreciated.

Many thanks,

-Tim

NSP wrote:Yeah, thanks Dave.
Found the diagram that I needed. This forums a great resource, thanks to all for sharing.

Image

Peace,

-Tim


Image
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Re: OBEL issues...need suggestions.

Postby tigerstrat » Fri Nov 25, 2011 11:26 am

You probably want to have just the one ground wire coming from your TRS jack. The wiring you described amounts to what is called a "ground loop" (http://en.wikipedia.org/wiki/Ground_loop_(electricity)), although I don't see how it could account for the your effects settings changing on their own; more likely you would just be getting a lot of unwanted noise. I would rewire the box correctly and see if you still have these issues.
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Re: OBEL issues...need suggestions.

Postby NSP » Fri Nov 25, 2011 11:38 am

I just rewired the junction box and the problem still persists.

I then removed the loop altogether by wiring the buffer directly to the 25k volume pot input and running straight through the effects chain and everything is fine. The problem is somewhere in the loop?
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Re: OBEL issues...need suggestions.

Postby JonnyBoy » Fri Nov 25, 2011 3:11 pm

you're running a buffer in the circuit with the 25K pot right? I would also make sure there are no unintentional groundings too. check loose wires and that all the wires are soldered properly and protected with electrical tape when bare. Usually for me with projects like these you can swear that you have it wired right, and believe it defensively, while its not. I would start over step by step and eliminate that possibility. One time I had a wire crossing with my capacitor coming off my tone pot, and it was wired properly so I didn't look at the wiring close enough. I have also had issues with switches I have soldered a few times melting and becoming faulty. you can test that theory by wiring up the effects loop without the switch to see if that circuit is clean. Good luck!
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Re: OBEL issues...need suggestions.

Postby JonnyBoy » Fri Nov 25, 2011 3:18 pm

PS: I had the same issue with my Qtron screetching too, I found out it was my OBEL junction box had something wrong with it. I dunno what, since it is a simple machine so to say. When I made a new one, with new stuff, the problem stopped.Make sure you don't have the OBEL wires going backward too. :D
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Re: OBEL issues...need suggestions.

Postby waldo041 » Fri Nov 25, 2011 6:34 pm

ensure your guitars tip is send and the ring is receive. leave the mono plug in the output jack, but don't plug it into the amp. this is needed to turn the battery on. next, plug another MONO cable into the effects loop jack and plug the other side into the amp. switch the effects loop on, and you should get full signal with no volume control. this test will tell you if your OBEL is sending a signal. if it does, then your problem lies on the receive side or your junction box.

peace,
waldo
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Re: OBEL issues...need suggestions.

Postby NSP » Sat Nov 26, 2011 8:05 am

waldo041 wrote:ensure your guitars tip is send and the ring is receive. leave the mono plug in the output jack, but don't plug it into the amp. this is needed to turn the battery on. next, plug another MONO cable into the effects loop jack and plug the other side into the amp. switch the effects loop on, and you should get full signal with no volume control. this test will tell you if your OBEL is sending a signal. if it does, then your problem lies on the receive side or your junction box.

peace,
waldo


Thanks Mike,

I was hoping you'd provide some insight. I just performed the test you suggested and it did confirm that the OBEL is sending a signal....and my effects were functioning properly during the test. I will re-do the receive side of the junction box and see if that fixes it. Is there a chance my stereo cable could cause the problem I'm having? It's a brand new Cable Up brand TRS. That seems to be the only other part of the equation that could cause a receive issue. I'll report back after I do some more re-wiring.

-Tim
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Re: OBEL issues...need suggestions.

Postby NSP » Sat Nov 26, 2011 12:54 pm

Aright, I still haven't solved my problem, but it's got to be narrowed down to either the box or my stereo cable? Can anyone see anything in this photo that would cause a problem?

Thank you.

Image





NSP wrote:
waldo041 wrote:ensure your guitars tip is send and the ring is receive. leave the mono plug in the output jack, but don't plug it into the amp. this is needed to turn the battery on. next, plug another MONO cable into the effects loop jack and plug the other side into the amp. switch the effects loop on, and you should get full signal with no volume control. this test will tell you if your OBEL is sending a signal. if it does, then your problem lies on the receive side or your junction box.

peace,
waldo


Thanks Mike,

I was hoping you'd provide some insight. I just performed the test you suggested and it did confirm that the OBEL is sending a signal....and my effects were functioning properly during the test. I will re-do the receive side of the junction box and see if that fixes it. Is there a chance my stereo cable could cause the problem I'm having? It's a brand new Cable Up brand TRS. That seems to be the only other part of the equation that could cause a receive issue. I'll report back after I do some more re-wiring.

-Tim
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Re: OBEL issues...need suggestions.

Postby NSP » Sat Nov 26, 2011 1:42 pm

And this is the cable I picked up for the loop. Any issues with this?

http://www.fullcompass.com/product/349228.html


NSP wrote:Aright, I still haven't solved my problem, but it's got to be narrowed down to either the box or my stereo cable? Can anyone see anything in this photo that would cause a problem?

Thank you.



NSP wrote:
waldo041 wrote:ensure your guitars tip is send and the ring is receive. leave the mono plug in the output jack, but don't plug it into the amp. this is needed to turn the battery on. next, plug another MONO cable into the effects loop jack and plug the other side into the amp. switch the effects loop on, and you should get full signal with no volume control. this test will tell you if your OBEL is sending a signal. if it does, then your problem lies on the receive side or your junction box.

peace,
waldo


Thanks Mike,

I was hoping you'd provide some insight. I just performed the test you suggested and it did confirm that the OBEL is sending a signal....and my effects were functioning properly during the test. I will re-do the receive side of the junction box and see if that fixes it. Is there a chance my stereo cable could cause the problem I'm having? It's a brand new Cable Up brand TRS. That seems to be the only other part of the equation that could cause a receive issue. I'll report back after I do some more re-wiring.

-Tim
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Re: OBEL issues...need suggestions.

Postby NSP » Sun Nov 27, 2011 12:51 pm

This is really starting to drive me insane....

I think I have it narrowed down to some issue with the tone control circuit. To recap, I have a PRS with the 5 way rotary pick-up selector. The way it was/is wired has the hot out to the buffer then to the dpdt and to the input of 25k volume pot. The other side of the 5 way rotary (gnd?) goes to the center lug of the tone control and a .022uF cap going from the outside lug of the tone control to the input of the volume pot. I have everything grounded to the volume pot. Now when the loop is in bypass mode everything is just fine, but when I flip the switch for the loop my effects freak out. But, now I've discovered when the tone control is turned all the way in one direction that's when the effects are acting weird, and when I turn it back all the way the other direction they sound normal, but I lose signal and tone. Any thoughts??

-Tim
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Re: OBEL issues...need suggestions.

Postby waldo041 » Sun Nov 27, 2011 1:11 pm

NSP wrote:This is really starting to drive me insane....

I think I have it narrowed down to some issue with the tone control circuit. To recap, I have a PRS with the 5 way rotary pick-up selector. The way it was/is wired has the hot out to the buffer then to the dpdt and to the input of 25k volume pot. The other side of the 5 way rotary (gnd?) goes to the center lug of the tone control and a .022uF cap going from the outside lug of the tone control to the input of the volume pot. I have everything grounded to the volume pot. Now when the loop is in bypass mode everything is just fine, but when I flip the switch for the loop my effects freak out. But, now I've discovered when the tone control is turned all the way in one direction that's when the effects are acting weird, and when I turn it back all the way the other direction they sound normal, but I lose signal and tone. Any thoughts??

-Tim



any chance of pictures of your rotary wiring?

i don't think there should be a ground lug on the 5 way rotary so i am wondering why oneside of the tone control goes to "the otherside of the 5 way rotary (Gnd)?" and oneside to the volume control.

pictures would help.

peace,
waldo
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Re: OBEL issues...need suggestions.

Postby NSP » Sun Nov 27, 2011 2:48 pm

waldo041 wrote:
NSP wrote:This is really starting to drive me insane....

I think I have it narrowed down to some issue with the tone control circuit. To recap, I have a PRS with the 5 way rotary pick-up selector. The way it was/is wired has the hot out to the buffer then to the dpdt and to the input of 25k volume pot. The other side of the 5 way rotary (gnd?) goes to the center lug of the tone control and a .022uF cap going from the outside lug of the tone control to the input of the volume pot. I have everything grounded to the volume pot. Now when the loop is in bypass mode everything is just fine, but when I flip the switch for the loop my effects freak out. But, now I've discovered when the tone control is turned all the way in one direction that's when the effects are acting weird, and when I turn it back all the way the other direction they sound normal, but I lose signal and tone. Any thoughts??

-Tim



any chance of pictures of your rotary wiring?

i don't think there should be a ground lug on the 5 way rotary so i am wondering why oneside of the tone control goes to "the otherside of the 5 way rotary (Gnd)?" and oneside to the volume control.
pictures would help.

peace,
waldo


Hey Waldo,

Here's what I was sent from PRS based on my guitar set-up.

I have the hot out to the input of the buffer, then to the dpdt. The lug labeled ground goes to the middle lug on the tone control. The outside lug of the tone control then goes to the input of the volume control through a cap. This is how it was originally wired and sounds good when the loop is bypassed. But, as I said, once I engage the loop the tone control causes mayhem with the effects.
Image

Thanks for your help, I truly appreciate it.
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Re: OBEL issues...need suggestions.

Postby waldo041 » Sun Nov 27, 2011 5:08 pm

remove the .022uf of the tone control going to the volume pot and solder that where you have the buffers input at the hot output.

peace,
waldo
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Re: OBEL issues...need suggestions.

Postby NSP » Sun Nov 27, 2011 6:05 pm

waldo041 wrote:remove the .022uf of the tone control going to the volume pot and solder that where you have the buffers input at the hot output.

peace,
waldo


I had tried that earlier and just tried it again to no success. It really muted the signal. This is really starting to drive me nuts.... :?

Any other suggestions?

Thank you Waldo!
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Re: OBEL issues...need suggestions.

Postby waldo041 » Sun Nov 27, 2011 6:12 pm

remove the tone control completely. if this is a tone control issue, this will reveal that 100%.

peace,
waldo
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