Electrical noise issue, dont seem to know whats causing it.

[Distortion_101]

Hey guys

This is a long and confusing one.

This is my gear chain:
Ibanez SZ320 > T-Rex Diva Drive > Orange Rocker 15 Terror >[loop] Digitech Polara Reverb > Digitech Jamman Solo XT [loop] > Orange PPC112

All of this is powered by a Harley Benton Iso Pro2 Power supply. this power supply is supposedly all isolated, but only the 3 parts are (plug 1 and 2 (with adjustable voltage) and plugs 3 - 8)

Basically in the last few days i have noticed a hum/electrical noise develop on my rig. It can change from a electrical whine to a noise that sounds like a window is left slightly open and its windy outside. This changes depending on the plug i use on the PSU.
The noise is on both channels. Clean channel it gets quite loud past half volume. In the overdrive channel it gets quite louder with the gain past 2/3. Now I know the OD channel will hiss slightly with more gain, butthe amp is fairly quiet plugging my guitar in directly and having the pedals completely excluded.

Now I have tried to trouble shoot this by doing the following:

Changing cables,
Different slots on the power supply for each pedal. Keep in mind a different noise is produced with each slot
Remove each pedal to see what causes the noise (found this to be the Overdrive, even when its disengaged, the noise just gets louder when engaged as all overdrives make a little noise)
Try each pedal with a separate power supply (included wall wart with my Jamman, 9v with up to 2A current) and the noise still comes through

So I remove the overdrive pedal from the chain (but keep the power plugged in), the noise goes away. This lead me to believe the pedal is the issue not the power supply.
If i put the overdrive pedal in the loop, the noise goes away.
If I change the overdrive for a Blackstar LT-Dist the noise goes away.

Today I went into the store with my gear to try a different Diva drive and I have the same issue with the noise.

I just don't understand how this one pedal isn't working in the front of my amp. is it maybe a pedal issue?

What else could I be missing here? I don't think its tubes as the amp is quiet on full gain with no pedals. When the looper and reverb are in the loop its quiet. When the overdrive is connected to power but the guitar cable goes direct into the amp its quiet (so not the PSU).

Its literally only when the Diva drive (not even my other distortion pedal) is in front of the amp. This is driving me nuts!

I appreciate any assistance guys, thank you.

 

[Jacew]

Re: Electrical noise issue, dont seem to know whats causing it.

Hey guys

This is a long and confusing one.

This is my gear chain:
Ibanez SZ320 > T-Rex Diva Drive > Orange Rocker 15 Terror >[loop] Digitech Polara Reverb > Digitech Jamman Solo XT [loop] > Orange PPC112

All of this is powered by a Harley Benton Iso Pro2 Power supply. this power supply is supposedly all isolated, but only the 3 parts are (plug 1 and 2 (with adjustable voltage) and plugs 3 - 8)

Basically in the last few days i have noticed a hum/electrical noise develop on my rig. It can change from a electrical whine to a noise that sounds like a window is left slightly open and its windy outside. This changes depending on the plug i use on the PSU.
The noise is on both channels. Clean channel it gets quite loud past half volume. In the overdrive channel it gets quite louder with the gain past 2/3. Now I know the OD channel will hiss slightly with more gain, butthe amp is fairly quiet plugging my guitar in directly and having the pedals completely excluded.

Now I have tried to trouble shoot this by doing the following:

Changing cables,
Different slots on the power supply for each pedal. Keep in mind a different noise is produced with each slot
Remove each pedal to see what causes the noise (found this to be the Overdrive, even when its disengaged, the noise just gets louder when engaged as all overdrives make a little noise)
Try each pedal with a separate power supply (included wall wart with my Jamman, 9v with up to 2A current) and the noise still comes through

So I remove the overdrive pedal from the chain (but keep the power plugged in), the noise goes away. This lead me to believe the pedal is the issue not the power supply.
If i put the overdrive pedal in the loop, the noise goes away.
If I change the overdrive for a Blackstar LT-Dist the noise goes away.

Today I went into the store with my gear to try a different Diva drive and I have the same issue with the noise.

I just don't understand how this one pedal isn't working in the front of my amp. is it maybe a pedal issue?

What else could I be missing here? I don't think its tubes as the amp is quiet on full gain with no pedals. When the looper and reverb are in the loop its quiet. When the overdrive is connected to power but the guitar cable goes direct into the amp its quiet (so not the PSU).

Its literally only when the Diva drive (not even my other distortion pedal) is in front of the amp. This is driving me nuts!

I appreciate any assistance guys, thank you.

When you connect the drive in amp and PSU, does it makes noise if you unplug other pedals from PSU?

EDIT: It could be ground loop through PSU. When you unplug OD output from amp front you break taht loop. Whether it's plugged in PSU or not is irrelevant in that matter.

It's not clear from the post if noise in fact stays when:

a) only OD supplied with wall wart in front
b) without any pedals in loop and overdrive with PSU in front.
c) some pedal in loop with wall wart and only front OD in PSU.
d) one pedal in loop and OD in front both supplied with PSU.

 

[Gtrjunior]

Re: Electrical noise issue, dont seem to know whats causing it.

Usually that whining type noise is cause by a digital pedal needing to be on its own separate power supply. Try removing the pedals and adding one at a time back in until you find the culprit.

 

[aiaosu]

Re: Electrical noise issue, dont seem to know whats causing it.

Usually that whining type noise is cause by a digital pedal needing to be on its own separate power supply. Try removing the pedals and adding one at a time back in until you find the culprit.

I agree with this. I had a similar problem and had to move a couple digital pedals to their own supply. I also had an overdrive pedal with a buffer that was very picky where it was in the chain. If it was next to certain pedals, it would do strange things...noises,no sound, etc. I eventually got rid of it and moved on to something else less picky.

Sent from my LM-V405 using Tapatalk

 

[Distortion_101]

Re: Electrical noise issue, dont seem to know whats causing it.

When you connect the drive in amp and PSU, does it makes noise if you unplug other pedals from PSU?

EDIT: It could be ground loop through PSU. When you unplug OD output from amp front you break taht loop. Whether it's plugged in PSU or not is irrelevant in that matter.

It's not clear from the post if noise in fact stays when:

a) only OD supplied with wall wart in front
b) without any pedals in loop and overdrive with PSU in front.
c) some pedal in loop with wall wart and only front OD in PSU.
d) one pedal in loop and OD in front both supplied with PSU.

No change when the pedal is run off a battery. No change with different cables.

If I plug just the OD pedal into the PSU, the noise does drop substantially but there is a bit more than just guitar > Amp > Cab

Each output of my PSU has 300ma, with the output 1 and 2 being 500ma. so power is not an issue.

Ground loop could be a cause. the problem with this theory is when I remove the pedal from the front of the amp, and move it to the loop (no change in PSU outputs or anything else) the sound is gone. When plugging the LT-Dist in front of the amp, the sound is gone

Could it be something with the front end/pre-amp of my amp?

Using a wall wart just changes the sound signature of the noise regardless of which pedal I plug into.

It may be the buffer of the T-Rex as my LT-Dist works perfectly quietly when its in the same position?

 

[Jacew]

Re: Electrical noise issue, dont seem to know whats causing it.

Usually that whining type noise is cause by a digital pedal needing to be on its own separate power supply. Try removing the pedals and adding one at a time back in until you find the culprit.

I agree, though since it's silent with other OD pedals, it's certainly related to that Diva drive.

Isolated power supply should fix it too.

 

[Jacew]

Re: Electrical noise issue, dont seem to know whats causing it.

No change when the pedal is run off a battery. No change with different cables.

If I plug just the OD pedal into the PSU, the noise does drop substantially but there is a bit more than just guitar > Amp > Cab

Each output of my PSU has 300ma, with the output 1 and 2 being 500ma. so power is not an issue.

Ground loop could be a cause. the problem with this theory is when I remove the pedal from the front of the amp, and move it to the loop (no change in PSU outputs or anything else) the sound is gone. When plugging the LT-Dist in front of the amp, the sound is gone

Could it be something with the front end/pre-amp of my amp?

Using a wall wart just changes the sound signature of the noise regardless of which pedal I plug into.

It may be the buffer of the T-Rex as my LT-Dist works perfectly quietly when its in the same position?

Try out each of those a,b,c,d steps I posted. Then it's a bit more clear what's going on.

Just pondering random stuff that could cause it takes nowhere to fix the issue.

When you move OD into fx loop you can't have ground loop anymore, because PSU isn't connected to anything that's in front of the amp. That's why I suspected it was the issue.

EDIT: To be more clear, you can still have ground loop, but it's not an issue, because it's not through the preamp any more, that's most prone to cause that noise.

 

[Distortion_101]

Re: Electrical noise issue, dont seem to know whats causing it.

a) only OD supplied with wall wart in front
Still makes the noise

b) without any pedals in loop and overdrive with PSU in front.
Make a bit of a different noise, but still noisy

c) some pedal in loop with wall wart and only front OD in PSU.
Noisy with only the reverb and only the looper, but the reverb makes a bit more noise than the looper

d) one pedal in loop and OD in front both supplied with PSU.
definitely makes more noise than if the pedal in the loop is supplied with wall wart, but not as bad as all of them together

A new noise that has now started to form is that every 45 seconds or so (if i leave the amp on and guitar idle) it makes a scratchy prrrrr noise for about half a second then stops.

 

[Gtrjunior]

Re: Electrical noise issue, dont seem to know whats causing it.

Just spitballing here...
Your amp has a tube driven loop.
Try swapping a known good tube into that position...
Even failing preamp tubes (V1/V2) May be contributing to whatever noise you’re hearing from pedals in front of the amp.
Especially if these noises are a new development. It stands to reason the the problem isn’t you’re pedal setup/power if it wasn’t causing a problem prior to recently.

 

[Jacew]

Re: Electrical noise issue, dont seem to know whats causing it.

Yep. Since you get noise even without PSU or other pedals in loop it's either just problem that particula OD with you amp or more probably bad preamp tube.

 

[devastone]

Re: Electrical noise issue, dont seem to know whats causing it.

I haven't read this whole thread that closely, so I can't really add a diagnosis, but that Harley Benton power supply doesn't have isolated outputs. They are "semi" isolated, but share grounds, most if not all power supplies with isolated grounds have a real IEC AC power cord and do the AC to DC conversion in the box, basically, if it has a wall wart, it is more of a power distribution box and doesn't isolate all the outputs. And yes, I know they advertise it as isolated outputs, but they aren't.