I am trying to build a simple circuit to break a ground loop I am having on my pedalboard. I came up with this. This is put into a box so wires will not be exposed. Eventually on mini circuit board. I have two diodes 6a 500 volt and a 1 k resistor. I tested the circuit. It conducts power but is not eliminating the ground loop. The loop on the amp is fine. I have ine pedal and the power supply is a voodoo lab pedal power. It is isolated transformer type. Here is a pic of the schematic and the actual build. Can someone give me an idea why this is not breaking the ground loop? All units are being plugged into the strip. I broke into a household variety power strip and oassed tge ground wire through circuit. What am I missing?
Hum can be caused by many things.
1/ Not using star grounding.
2/ Having more or less than one earthing point.
1/ Not using star grounding.
2/ Having more or less than one earthing point.
Thanks for your response. I am aware if the multiple earthing point. If all units are going into the same outlet then where could the problem be coming from? I was thinking there may be something I did not consider? Are the values of resistor and diodes sufficient. Did I not do something on the build that is causing it to not be affective? Any continued ideas welcome.
My guess would be that your ground loop is not where you think it is, hence your attempted solution doesn't work.
If you want anyone to help you, you will have to describe the setup in more detail. How did you even incur a ground loop in the first place? I thought pedals generally used wall warts or internal 9 V batteries? Is there a literal loop somewhere?
I have a bit of a hunch - you aren't running a guitar amp (earthed) into a PC audio interface (earthed via PC) by any chance? This may involve making a cable that's making use of the balanced input then. unbal-signal --> hot, unbal-ground --> cold, shield only connected at input.
If you want anyone to help you, you will have to describe the setup in more detail. How did you even incur a ground loop in the first place? I thought pedals generally used wall warts or internal 9 V batteries? Is there a literal loop somewhere?
I have a bit of a hunch - you aren't running a guitar amp (earthed) into a PC audio interface (earthed via PC) by any chance? This may involve making a cable that's making use of the balanced input then. unbal-signal --> hot, unbal-ground --> cold, shield only connected at input.
Sgrossklass,
Thanks so much for taking the time to respond. You are right. Let me address.
1 i am using actual amp(s)
2. I am running modulation pedals through the loop on the amp.
3. The amp is a PRS Archon 50
4. The problem is when loop is engaged there is a slight hum.
5. Loop was tested and is not the problem
6. I am using Voodoo Pedal Power Plus as my power supply. All inputs are isolated and it uses toroidal trans.
7. I am convinced that the issue is truly a ground loop because there are multiple outlets competing for the singular earth.
8. I am researching how to create a singular earth path.
9. I am using IMac with plenty of HP(32gig ram) etc.
10. Using Pro Tools 2020
11. I am in the process of building longer barrel connector cable to move the power supply away from the pedals.
12. I have noticed when moving pedals there is a modulation of the hum.
13. It is not the guitar. It is completely shielded.
14. Amp is silent when loop is disengaged
15. Any suggestions welcomed
Thanks
Thanks so much for taking the time to respond. You are right. Let me address.
1 i am using actual amp(s)
2. I am running modulation pedals through the loop on the amp.
3. The amp is a PRS Archon 50
4. The problem is when loop is engaged there is a slight hum.
5. Loop was tested and is not the problem
6. I am using Voodoo Pedal Power Plus as my power supply. All inputs are isolated and it uses toroidal trans.
7. I am convinced that the issue is truly a ground loop because there are multiple outlets competing for the singular earth.
8. I am researching how to create a singular earth path.
9. I am using IMac with plenty of HP(32gig ram) etc.
10. Using Pro Tools 2020
11. I am in the process of building longer barrel connector cable to move the power supply away from the pedals.
12. I have noticed when moving pedals there is a modulation of the hum.
13. It is not the guitar. It is completely shielded.
14. Amp is silent when loop is disengaged
15. Any suggestions welcomed
Thanks
Ground loops aren't only created through AC outlets. You have narrowed onto this prematurely. We don't even know what your devices are? It would take a great deal more detail to actually analyze this in detail.
Suggest you start by analyzing every component in your signal chain. Start off by putting 0 pedals in your loop. Does it hum? Add 1 pedal. Does it hum? If no->take it out and try a different pedal. If yes->does it hum with both battery and AC power? Keep going.
Suggest you start by analyzing every component in your signal chain. Start off by putting 0 pedals in your loop. Does it hum? Add 1 pedal. Does it hum? If no->take it out and try a different pedal. If yes->does it hum with both battery and AC power? Keep going.
I have everything you have suggested. I appreciate you responding. As I said in the previous post I am going to build longer cables for power supply to give distance from amp and pedals
Again. All pedals have been tested in and out of loop. Loops was tested running a patch cable across send and return. Loop is fine.
More to come
Again Thanks
Again. All pedals have been tested in and out of loop. Loops was tested running a patch cable across send and return. Loop is fine.
More to come
Again Thanks
I think it's safe to say we don't understand what you are describing. You say you did "all that"; what were your results? Which ground are you trying to put the breaker in? The Voodoo Pedal Power Plus is fully isolated, so it should not cause a ground loop, and if that is the AC ground you tried the breaker in, of course it had no effect.
I tried to breaker in to a surge protector with 6 outlets.
2 6amp 500 volt diodes
1 (1k) resistor.
Tried running everything through that.
I have another separate outlet that is running computer. All guitar components are running through Furman power conditioners. I want to have everything run through my version of the ebtech hum reducer. This is a step by step process unique to my setup. I will eliminate variables as I go along.
2 6amp 500 volt diodes
1 (1k) resistor.
Tried running everything through that.
I have another separate outlet that is running computer. All guitar components are running through Furman power conditioners. I want to have everything run through my version of the ebtech hum reducer. This is a step by step process unique to my setup. I will eliminate variables as I go along.
According to your picture above, you have serial setup, but the pedal is parallel..
What I do when I have such issues I remove the all either right or left inputs and then listen to the outcome. If it loops by your pedal then it could be that it makes that loop within input jacks, I see you have an iMac in the chain..The Imac itself can be the point of producing the ground loop..
Loop will exist if the ground finds an easier way to return then the one which was created..
then also check all shielding.
Make sure the wall outlets which feeding your devices are all in one line with line zero.. With this I mean if you have devices which are not using three point Plugs for the line, turning them around to find our if these are in line, with the others.
As everyone else stated, it's hard to tell, go step by step and make sure each part in that line is grounded you can use a simple phase checker for that.
Regards Chris
What I do when I have such issues I remove the all either right or left inputs and then listen to the outcome. If it loops by your pedal then it could be that it makes that loop within input jacks, I see you have an iMac in the chain..The Imac itself can be the point of producing the ground loop..
Loop will exist if the ground finds an easier way to return then the one which was created..
then also check all shielding.
Make sure the wall outlets which feeding your devices are all in one line with line zero.. With this I mean if you have devices which are not using three point Plugs for the line, turning them around to find our if these are in line, with the others.
As everyone else stated, it's hard to tell, go step by step and make sure each part in that line is grounded you can use a simple phase checker for that.
Regards Chris
When you say turning devices non 3 prong devices around what do you mean?
Also, how do you do a phase check at each step? What would I be checking? Do I plug in pedals?
Thanks
Also, how do you do a phase check at each step? What would I be checking? Do I plug in pedals?
Thanks
Last edited:
I meant if you have devices which using these small transformers, with only two pin connector to wall outlet, pull out and then plug in with the pins turned from left to right.
If one of the pedals is out of phase then you can use a phase checker and hold against the CASE, if metal may you will see some small response, that the phase checked light up.. this doesn't mean that there is Voltage on the housing but it means that it not in phase with the other devices. More if you have battery driven ones, then using a OHM METER and check between for throughput of Ground on between all devices.
Using OHM METER it must show a SHORT CONNECTION from HOUSING to next housing of each pedal to the next pedal..
Myself would disconnect the iMAC in first place, these are always a problem...
Using a Imac as Media feed, (Video) and having sometimes this problem when the jacks at the back are not real inserted good.. Like everything with mac... Cheap made..these 1/8 inch jacks on the back have bad GND connection inside, because running through a chip which let you switch them between Line out and Loudspeaker out.. and therefore is a possible point of creating ground Problems. Check cables for bad connector connections.
Your welcome
If one of the pedals is out of phase then you can use a phase checker and hold against the CASE, if metal may you will see some small response, that the phase checked light up.. this doesn't mean that there is Voltage on the housing but it means that it not in phase with the other devices. More if you have battery driven ones, then using a OHM METER and check between for throughput of Ground on between all devices.
Using OHM METER it must show a SHORT CONNECTION from HOUSING to next housing of each pedal to the next pedal..
Myself would disconnect the iMAC in first place, these are always a problem...
Using a Imac as Media feed, (Video) and having sometimes this problem when the jacks at the back are not real inserted good.. Like everything with mac... Cheap made..these 1/8 inch jacks on the back have bad GND connection inside, because running through a chip which let you switch them between Line out and Loudspeaker out.. and therefore is a possible point of creating ground Problems. Check cables for bad connector connections.
Your welcome
OP, what is that central "pedal power" thingy? You're not connecting power ground on all the pedals together, are you? This may be your ground loop right there, as the pedals are likely to be power ground referenced signal-wise on input and output. You need galvanic isolation between all the pedals, so that's basically one wall wart per pedal. Yes I know that amounts to a big mess.
Not sure how others with a pedal board are dealing with this - use a whole lot of 9 V batteries I guess?
Not sure how others with a pedal board are dealing with this - use a whole lot of 9 V batteries I guess?
Thanks Hpro I appreciate your information.
Sgrossklass - The Pedal Power does According to this
Isolation is more than fixing ground loops.
Ground loops cause hum, and the solution is to break the unwanted ground path. Isolation is the best way to do it. Unlike other power supplies, Pedal Power 2 PLUS isolates EVERY output. This eliminates tone robbing interaction between units. Now you can properly power everything from vintage overdrives to modern digital marvels that others just can’t!
Proprietary balanced transformer makes it possible.
A typical transformer, like those used in a wall wart, creates a large magnetic field that causes hum in any audio path near it. Pedal Power 2 PLUS uses a custom designed, ultra-low noise toroidal transformer, with separate balanced windings for every output. Now even the most sensitive pedals can be dead quiet.
Switching power supplies aren’t for everything.
What’s good for charging a cell phone is NOT good for your pedals. While digital switching power supplies are small and inexpensive, they also generate unpredictable transients and extraneous noise. Pedal Power 2 PLUS uses an audiophile quality linear supply for consistently stable, clean, pure power.
Sgrossklass - The Pedal Power does According to this
Isolation is more than fixing ground loops.
Ground loops cause hum, and the solution is to break the unwanted ground path. Isolation is the best way to do it. Unlike other power supplies, Pedal Power 2 PLUS isolates EVERY output. This eliminates tone robbing interaction between units. Now you can properly power everything from vintage overdrives to modern digital marvels that others just can’t!
Proprietary balanced transformer makes it possible.
A typical transformer, like those used in a wall wart, creates a large magnetic field that causes hum in any audio path near it. Pedal Power 2 PLUS uses a custom designed, ultra-low noise toroidal transformer, with separate balanced windings for every output. Now even the most sensitive pedals can be dead quiet.
Switching power supplies aren’t for everything.
What’s good for charging a cell phone is NOT good for your pedals. While digital switching power supplies are small and inexpensive, they also generate unpredictable transients and extraneous noise. Pedal Power 2 PLUS uses an audiophile quality linear supply for consistently stable, clean, pure power.