Guitar processor noise...? BZZZZZZ!

pishta

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Hey, some guys have guitars in their garages too? <My boy has a Digi Tech RP155 processor that goes between his Bass and the Crate BX100 amp. Holy smoke, this thing has developed a hellacious buzz in it! We can run the Ibanez bass directly to the amp and it cleans up 95% of the buzz but if you run it in series, forget about it. Does it on a Fender 15 amp too. Did I lose a ground on the input jack or do these things just go bad? Bass is a little buzzy too, Ill have to check that plug too and the cords are by no means new. Any buzz killers out there? The RP155 uses a 9vAC power in from a common brick, weird as I thought it would use a DC power supply for a cleaner voltage. processor is plugged into one power outlet (extension cord) while the amp is in another. processor is a 2 prong, IIRC the amp is too as these power jacks in this old house are not 3 prong unless I changed them out and I didt do this in the bedroom yet.
 

Slantsix64

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Might be the bass input ground, when run threw a pedal it probably amplifies the buzz???
 

Dana67Dart

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You could test the ground by getting some wire and attach to a bare water pipe the cleaner and former the contact the better.

One way would be to Scotch Brite an area and then put a hose clamp on it tuck the wire between the pipe and the hose clamp and tighten.

Then take the other end and touch exposed metal of the devices starting at the farthest from the ac outlet.

If the buzz goes away you know there is a bad ground between them.

This assumes that your pipe is copper or iron and is tied to the house electrical ground.
 

pishta

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@Slantsix64 Sounds entirely possible. Where does the ground wire (from the bridge) go to, one of the pots? I can run some contact cleaner into the pots to try and clean them up.
 

jimmer

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Single coil pickups hum .
Hence humbuckers .
So bad grounds will amplify the prob.
Check the cords too though.
Bad cords will make noise but still work.
 

pishta

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The bass has no battery in it so Ill have to dig into the wiring to find if I lost a solder joint. It was a bass that a guy put together for me so who knows what the electronics look like. I see ground in all these schematics....where is the ground in the guitar.. The ring of the jack? I see a few schematics that show a wire going to "hardware ground" but nothing that look like an external connection. Is that just a reference to common ground through the cord?
ibanez-gio-wiring-diagram-4.jpg
 

67Dart273

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**** Pishta LOLOL You oughta know how to wire a "tip sleeve" connector. Yeh the sleeve is one conductor and the shield. This is actually poor design. Much better if it ran a "shield only" plus two BALANCED wires (telco style) for the signals

I assume you've tried moving / wiggling/ shaking components/ cables to see loose connnections or maybe if SOMETHING EXTERNAL is inducing noise.

Might be the power supply is overloaded or defective? Get a meter on a DC point and look for ripple with the meter in AC mode. Ground the input of the offending component and see if it still buzzes

Take your meter and look for continuity to ground on the output jack. Maybe it's capacitive coupled and is putting unwanted "leakage" through into the amp

Also take your meter and with the component and then the amp powered check for EITHER DC present from the outlet 3rd wire to the audio jack grounds. Should be NONE

AND make darn sure the outlets are actually grounded properly--and that there is NO AC from 'actual ground' like a water pipe to the 3rd wire of the outlet/ strip/ etc

My ex super at the wheelchair joint plays guitar and played way back when he was young. He and I have discussed some "gigs" he got into where a guy got shocked or damn near electrocuted by cords, mics, etc, that were "hot" because of poor grounding. Back then lots of places he played had poorly wired or non grounding outlets
 
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Ironracer

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@Slantsix64 Sounds entirely possible. Where does the ground wire (from the bridge) go to, one of the pots? I can run some contact cleaner into the pots to try and clean them up.
Yes , contact cleaner is OK. Cords WILL screw ya! Jamming since the early 80s.. played in 2 signed bands, and had my Own Music payed on the leading Rock station Tampa Bay
 

eekvonzipper

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2 Prong Cords to Both the Amp And The Pedal?!? Well, Did that ever work before or is it suddenly making a new noise?
You should try it on a Wet Garage Floor in Bare Feet and That will Quickly let you know if... No, Don't Try That!
If That Crate Amp has a Three wire cord you should at least have an adapter on it that screws to the outlet...
and try the wire to a pipe and touch it to the Bridge of the Bass, if nothing changes there put everything on carpet to isolate it from the floor and try again?
 

pishta

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Yeah, tip and ring is pretty easy...tip and sleeve?....mind blown! LOL It doesn't get a lot of playing time and its on the wall for months at a time. Ill tackle that bass jack and clean em all good. Ill check the cords too as he says his guitar does it too.
 

memike

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My friend had this problem in his bass amp, seems the 6 string guitar amps didn't, I ran a ground wire to his face plat to the wall outlet, then to his amp housing, cleaned it up.
He had fluorescent tubes on his wiring to his power supply that was the main reason.
But I am sure all these musicians here have you took care of, a floating ground is almost a necessity like southwest bell used, as well as some or rooms.

Good luck and keep on Jamin.
 

pishta

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fluorescents....I have a O-scope in the garage under 8 F40CW bulbs. Those are noisy for sure. I turn them off and use the LED flood over the bench when I'm scoping. Them wall wort DC convertors are crap too. I had one running a cheap signal generator and my scope went crazy, even when it wasn't looking at a signal. Unplugged it...flatlined the scope trace back to normal. Probably a leaking filter cap in the PS.
 

memike

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Well, I hope you get it figured out, I play drums most the time, bless roady :D so I do understand.
Love to play my acoustic

imagejpeg_0(4).jpg
 

67Dart273

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AC interference can be truely weird. Back in the 90's I had a radio amateur friend who had an Astron variable DC power supply on his desk. I honestly don't remember "which way" this went. Either the power supply would screw with a dimmable desk lamp, or the other way around. We had a similar situation at the Motorola shop for a short time. Something about a soldering station and a power supply or lamp that would interact. "No good logical reason." One of them was generating some sort of "hash" on the line that was "getting into" the other component.
 

pishta

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Well, I hope you get it figured out, I play drums most the time, bless roady :D so I do understand.
Love to play my acoustic

View attachment 1715893374
He plays his Martin acoustic 98% of the time so this amp stuff is not daily. He loves that RP155 though, can make short loops and beats as well as about 85 amp cabinet emulations. $20 at Goodwill! :thumbsup:
 

Dana67Dart

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Back in the late 90s to early 2000s when cell phones were just coming into their prime.

A friend could tell you he was about to get a call.

Her PC speaker would pop and click a few times then the phone would wake up and start to ring.

My assumption was that the phone was sitting in a low power state untill a tower pinged it, then it would go to higher power state and reply. The noise I'm guessing was the cell phone signaling the tower.

We proved it out (that the cell was the interferiance) with numerous blind tests.
 

cosgig

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Some amps have a reverse polarity ground switch, if it does try clicking the other way. Also, if you can, flip the 2 prong adapter and plug it in the other way, I had an old light rack with wonky wiring that would shock you unless all of the lights were plugged in the “right” way.

does the buzz go away or diminish if you lay your hand on the strings? That would indicate a bad ground in the cord. An old or crappy cord is notoriously famous for this, that’s why I buy the best cords that money can buy, with an over the counter guarantee. My best cords cost over $130 for a 20’ cord, but they’re well worth every penny.
 

pishta

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Some amps have a reverse polarity ground switch, if it does try clicking the other way. Also, if you can, flip the 2 prong adapter and plug it in the other way, I had an old light rack with wonky wiring that would shock you unless all of the lights were plugged in the “right” way.

does the buzz go away or diminish if you lay your hand on the strings? That would indicate a bad ground in the cord. An old or crappy cord is notoriously famous for this, that’s why I buy the best cords that money can buy, with an over the counter guarantee. My best cords cost over $130 for a 20’ cord, but they’re well worth every penny.
interesting.....it does make a difference when he touches the strings...So a cord ground would be visible with an OHM meter across the tip and ring? A ground is a ground so Ill have to get the meter out and start Ohming out the bridge to the sleeve of the plug, the tip and ring of the cord and the RP155's continuity. It should be one big ground loop between the bass bridge and the amp ground. 10-4
 

67Dart273

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Has something changed? Any new cables? Different guitar? Did he rewire something in the guitar, replace a pickup, etc? This almost sounds as if somehow the shield conductor got connected to the "hot" side (center conductor)

You might go through your cables. If the plug shell can be unscrewed (not molded) make sure the shield is actually connected to the sleeve on both ends. Make sure the guitar is wired appropirately. I spose it's very possible for a pickup to be defective, and either have the hot lead shorted to the metallic parts of the pickup, or mis-wired that way
 

pishta

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OK, I think I narrowed it down to 2 possible faults. 1 was the jack in the bass was 6 colors of ugly inside. This model but 30 years old.
H70976000001000-01-500x500.jpg

This looks to be a stereo jack (3 lugs) that the guy put into the bass and the contacts inside didnt seem to show continuity to the cable end. Tip was fine, it as the ring/shield that wasnt making a connection. Then I started probing the cable and determined the braid/shield was possible open so I cut it back and tried to solder it back on with limited success, wrong tip on iron. The buzz has softened considerable but its still there, movement of the cable causes huge noise. The jack is jacked and Ill get a new one tomorrow if my electronics store has a deep panel threaded mono socket. The other cord was not good either so 2 new cords on order and that will give me a chance to attempt to reterminate the old cables with 4 new untarnished ends.
 

67Dart273

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If he put a stereo jack in there, the ring contact may be interfering, and you must make sure that the shield and tip actually go where "sposed" to. Sound like you are on the right track

Years ago, when installing the E911 stuff, this is when CRT monitors were getting BIG. And of course the fed-assisted 911 projects could afford BIG. And the BIGGER the CRT, the more RF noise they make.

We had installed a Motorola CRT "Centracom" radio control console, which has a balanced cable comes out, wherever you want to mount it under the desk, etc, for the operator's headset/ mic. That cable, balanced, was deemed "not needed" to be shielded by Motorola. Well, "news." It needed to be..........I actually found an old piece of coax in the sheriff's "junk box" in the basement, stripped it and pulled off a length of braid, and bunched it up "Chinese finger" style, and worked it over the top of the cable. Then grounded the end next to the console. I was a "hero."
 

royslead

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Late to the table on this, but you can try cleaning the jack on the bass by spraying De-Oxit on the cable jack and working it in and out of the bass jack. I didn't see it before; but ground path should be present from sleeve terminal on jack, to the back of each pot, ( the pickup(s) will normally have a ground wire / shield soldered to each pot, too), pickup switch, and to bridge. Some manufacturers use shielding paint in the electronics cavity and have a ground wire attached to the wood through the paint. Some use shielding on the back of the pickguard, to combat this noise / hum. I don't know about a polarity switch on the back of amps, but there is often a ground lift, and the RP155 may have one too. Like Ironracer, I too, have been jamming since the early eighties; but unlike Ironracer, though I've been in a couple good rock bands, never wrote anything note-worthy.
 
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