Update on noise gate, effects loop 5150-III

TheGreatGreen said:
Is the 5150 III a 50w or a 100w amp?

Does the noise still happen if you simply take a small patch cable and plug one end into "Send" and the other into "Return" while the loop is active?

Also, if it's a 100w amp, I'm with @blackie13 in that it could be a bad preamp tube. The 50w 5150 III's don't have tube driven effects loops but the 100w amps do.

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I have the 50 watt head. I was hoping it had an effects loop tube. I guess I can swap out the preamp tube but those seem to be working OK.
 
At this point I think I may have to take it to a service center. I don't know if they'll be able to actually help or if it will end up being just diagnosed as "normal" or "typical" but definitely is that loop. I unplugged everything, tried other cables, sprayed Deoxit, etc and still was that noise. I would say it could be my house wiring but should be the whole amp if that is the case.
 
What is your power supply for your pedal board? I had the same problem with a few of my amps until I ditched the Onespot wall wart and used my bigger board with the Truetone CS7 on it. With pedals out in front and in the loop all powered by a Onespot (because I only needed a couple pedals), I created a ground loop. You need to use isolated power outputs for each section of the chain if you aren't already.
 
grimmchaos said:
What is your power supply for your pedal board? I had the same problem with a few of my amps until I ditched the Onespot wall wart and used my bigger board with the Truetone CS7 on it. With pedals out in front and in the loop all powered by a Onespot (because I only needed a couple pedals), I created a ground loop. You need to use isolated power outputs for each section of the chain if you aren't already.
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I have a Voodoo Lab Power Supply but I'm getting the noise even with no pedals plugged in. I have my amp and pedalboard plugged into a power strip I just bought to get rid of noise and hum.
 
Do you still get noise if you plug the guitar into the guitar effects return ?. If it's quiet then your noise is in the pre amp section... If it's still noisy then it's an electrical ground loop in the amp.
 
Geo said:
Are you plugging into a grounded outlet? And is the outlet properly wired?
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Yes for both of those but definitely a good point and something I can play with. I plugged the amp into a separate wall socket from the pedalboard for shits and giggles.
 
Bash_Man said:
Do you still get noise if you plug the guitar into the guitar effects return ?. If it's quiet then your noise is in the pre amp section... If it's still noisy then it's an electrical ground loop in the amp.
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Just so I'm understanding you correctly, are you talking about me plugging a guitar cable into the return of the effects loop? If so, I did that and it was very noisy.
 
romanianreaper said:
Just so I'm understanding you correctly, are you talking about me plugging a guitar cable into the return of the effects loop? If so, I did that and it was very noisy.
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Do you have another 12ax7 to try in either the loop tube and/or phase inverter sockets ?

I know the inverter shouldn't cause noise but worth a try I guess.

Cheers
 
At the advice of a local guy a a store near me, I used a pedal with battery, instead of plugged in, and ran it thru the effects loop. He told me that would at least cut out any issues coming from two devices being plugged into different outlets, same outlets, etc. The noise was still there so according to him, that suggests a bad ground I'm the loop.

Since it is an EVH service center, they have a guy that can look into it and fix it. I'm sure it is a badly soldered connection or something.
 
romanianreaper said:
At the advice of a local guy a a store near me, I used a pedal with battery, instead of plugged in, and ran it thru the effects loop. He told me that would at least cut out any issues coming from two devices being plugged into different outlets, same outlets, etc. The noise was still there so according to him, that suggests a bad ground I'm the loop.

Since it is an EVH service center, they have a guy that can look into it and fix it. I'm sure it is a badly soldered connection or something.
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Lets hope that fixes it. Keep us updated please.
 
On a whim I got a preamp tube for the PI spot, just in case there was some weird thing going on there. Didn't do anything of course. I found a tech yesterday, so going to just have them look at it. I'm sure it is an easy fix and maybe a wire nit soldered correctly, etc.
 
romanianreaper said:
Just so I'm understanding you correctly, are you talking about me plugging a guitar cable into the return of the effects loop? If so, I did that and it was very noisy.
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(Necro thread, so this is for future generations)

No. Your guitar would still plug into whichever pedals feed the front of your amp. Or, your guitar could even plug directly into the amp.

Then, take a SEPARATE cable and plug one end into amp fx send, and the other end into amp fx return (this is "jumpering").

What this does is engage the signal/circuitry of the amp fx loop, to check for noise. And since during the jumper test, no pedals are present in the amp fx loop, you can determine whether the noise you've experienced has been caused by the PEDALS in your loop, or the loop itself.

ie: if there is still noise during the test, it's coming from the amp fx loop; gating your loop pedals is not going to help.
 
I’m sure the tech will fix it. It sounds like a dodgy FX loop. If it still persists, try plugging the guitar directly into the FX return and that could highlight a power tube issue.

If not, it could be a defective cable.
 
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