By the way...when I get radio transmission interference through my amp(s) it's not faint. It's as loud as "Hold Music" on a phone call.
debug hum er rations
- Thread starter eSGEe
- Start date
By the way...when I get radio transmission interference through my amp(s) it's not faint. It's as loud as "Hold Music" on a phone call.
What I can’t seem to communicate is that by connecting all four pots, and anything else, to the conductive copper shielding...you effectively give them a better connection to ground. If there was a fault in your circuit boards ground plane, you gave it another path to ground, and perhaps that is why it is quiet now.
OP
eSGEe
Ferengi Ambassador of Trade
got that
but expolajin the other 6 guitars ----they cant ALL have bad grounds --and they are not ALL PCB gibsons
obviously your guitar in the audio isnt and or wasnt doing what mine are doing-- ive not really ever had them do what mine are doing--
Im guessing (uneducated of course) because I sit the corner (eating crayons) with a laptop--- a desk top--- 2 cell phones (all sucking WIFI from another room) --and lighting ---
in a 20+ year old double wide-- in swampapotamia (
ty cheap wiring) (forgot the window A/c unit 3 feet away---) and the amps are sitting 6 feet away---that all that is causing interference.
--some guitars/pups pick it up more--
when on "10" the output "overrides" the hum -- decrease the pickup output the hum takes over????
I dunno -- all I know is -- shielding fixed it (yeah)
now with the debugger IU am hoping to learn if I have to shield ALL the others --- or if I Can just plug into the EH and RAWK baby
but expolajin the other 6 guitars ----they cant ALL have bad grounds --and they are not ALL PCB gibsons
obviously your guitar in the audio isnt and or wasnt doing what mine are doing-- ive not really ever had them do what mine are doing--
Im guessing (uneducated of course) because I sit the corner (eating crayons) with a laptop--- a desk top--- 2 cell phones (all sucking WIFI from another room) --and lighting ---
in a 20+ year old double wide-- in swampapotamia (
ty cheap wiring) (forgot the window A/c unit 3 feet away---) and the amps are sitting 6 feet away---that all that is causing interference.--some guitars/pups pick it up more--
when on "10" the output "overrides" the hum -- decrease the pickup output the hum takes over????
I dunno -- all I know is -- shielding fixed it (yeah)
now with the debugger IU am hoping to learn if I have to shield ALL the others --- or if I Can just plug into the EH and RAWK baby
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Why did my guitar pick up a radio station?
I was playing my guitar (humbuckers), and I hear a very faint noise in the background. I turned the amp up some more and behold, I hear a radio talk s...
Does your amp pick up RADIO SIGNALS?
Story... Bought a 4K amp. It came in the mail. Plugged it in. Heard AM radio stations coming through the speakers. Called the maker. He all but said I was crazy, that he'd never heard of his amps doing that. Tried to resolve problem. Ultimately got a refund. Have gone into 2 shops since then...
www.thegearpage.net
Same condition with PCB's or vintage 1950's Gibson wiring. I've shielded 20 guitars in 3 months - ALL GIBSON'S - and all behaved the same way. Several brand new Gibson's at our local Guitar Sinner exhibit the exact same symptoms, 30 miles from my home studio.
OP
eSGEe
Ferengi Ambassador of Trade
Found this on anotehr forum
https://www.diystompboxes.com/smffo...rkhkjarbtmcsai8ut84re3c16&action=profile;u=13
Re: Why does my guitar hum when I turn the volume down?
« Reply #2 on: June 27, 2013, 04:40:42 PM »
You're changing the effective resistance between the amplifier or pedal input and ground.
As a simplified view, imagine your guitar as one pickup feeding a volume control, and the wiper of the volume control wiper going out to the output jack. When the wiper is at max, the resistance the amp/pedal input sees to ground is the total resistance of the volume pot in parallel with the pickup inductance and resistance. For a 2H pickup inductance the impedance is maybe 4K to 8K resistance and 753 ohms or so inductive. This is the opposite of the "lose treble by loading" paradigm; at low frequencies, the inductive impedance vanishes. So the line to the amp/pedal is held to ground by a few K ohms.
At minimum pot setting, it's tied to ground.
In the middle, the impedance to ground is the parallel of the upper and lower halves of the pot resistance, which is 62.5K for a 250K pot and 250K for a 1M pot. So the cable is much higher impedance at the middle resistance position. Easier for hum to get in however it does get in.
https://www.diystompboxes.com/smffo...rkhkjarbtmcsai8ut84re3c16&action=profile;u=13
Re: Why does my guitar hum when I turn the volume down?
« Reply #2 on: June 27, 2013, 04:40:42 PM »
You're changing the effective resistance between the amplifier or pedal input and ground.
As a simplified view, imagine your guitar as one pickup feeding a volume control, and the wiper of the volume control wiper going out to the output jack. When the wiper is at max, the resistance the amp/pedal input sees to ground is the total resistance of the volume pot in parallel with the pickup inductance and resistance. For a 2H pickup inductance the impedance is maybe 4K to 8K resistance and 753 ohms or so inductive. This is the opposite of the "lose treble by loading" paradigm; at low frequencies, the inductive impedance vanishes. So the line to the amp/pedal is held to ground by a few K ohms.
At minimum pot setting, it's tied to ground.
In the middle, the impedance to ground is the parallel of the upper and lower halves of the pot resistance, which is 62.5K for a 250K pot and 250K for a 1M pot. So the cable is much higher impedance at the middle resistance position. Easier for hum to get in however it does get in.
It only takes one faulty connection in the ground plane to create an issue similar to what @eSGEe originally described. He never mentioned radio station or transmission receiving, just hum that increased when he turned down the volume...that went away when he effectively re-grounded the entire circuit.
In my experience, with my guitars, the volume works as advertised.
I’ve had two occasions when it hasn’t. One was a bad solder joint at the neck pickup volume pot - a ground wire. The other was a faulty ground solder joint in a LP style guitar pickup switch harness.
In my experience, with my guitars, the volume works as advertised.
I’ve had two occasions when it hasn’t. One was a bad solder joint at the neck pickup volume pot - a ground wire. The other was a faulty ground solder joint in a LP style guitar pickup switch harness.
I get $200.00 parts/labor to shield a guitar and I am constantly busy...and several are vintage Les Paul's that cost more than my home....and several of these have had aftermarket wire harnesses installed by another Luthier and the problem remained unchanged, even with all new electronics.
Shield it and it's totally quiet. Go figure...
Shield it and it's totally quiet. Go figure...
Dont even get me started on the pile of shorted Gibson pickups I have here...
They should have named it the "Bah-Humbug" pedal...
I can not expolajin(I don’t know what that is
). I can’t explain it either. Most of your examples are single coils...it seems. But the symptoms you describe are ground fault(to me)...like the article you quoted.RF doesn’t usually get in through a pot....it’s picked up by the pickups(those big copper coils).
And @Robert Herndon
He has 7 guitars and bass guitars presenting symptoms. Only 2 are Gibson. So maybe we can settle down on slagging one particular “brand name” here.
I can not expolajin(I don’t know what that is
RF doesn’t usually get in through a pot....it’s picked up by the pickups(those big copper coils).
And @Robert Herndon
He has 7 guitars and bass guitars presenting symptoms. Only 2 are Gibson. So maybe we can settle down on slagging one particular “brand name” here.
I have a growing collection of Gibson pickups that are either totally dead, or buzz/hum/squeal so badly they are unplayable. Ask @Mitch Pearrow SJMP ....
....and as you mention the same brand for what now? The fourth or fifth time? I’ll take the opportunity to reiterate the list of instruments that @eSGEe is having problems with...
The total is actually 8...including the one he just shielded/re-grounded.
3 Gibson(and I don’t believe there’s much “Gibson” left in the electronics of the 62 EBO-P)
3 Squier
1 Warwick
1 Peavey(and Peavey usually factory shielded their guitars and basses pretty well...I’ve been inside a few, chasing bad solder joints...go figure).
Let's just say...."Shielding Is My Business --- And Business Is Good..."
I think you missed something in Adrian's post.
Either way, and in any event, the problems are well documented from a number of sources, whether you choose to believe the phenomena or not doesn't change anything.
Bring your most trusted guitar up here...and if it's not copper shielded, it will play "constant country KFROG" as soon as you plug it in...your amp, house amp...makes no difference.
I'm glad you don't have these issues where you reside. It took me a while to figure out how to address the problem and shielding was an affirmative solution.
I am very interested in the Hum-Debugger, but I do not think it can counteract RFI transmission from two way radio and FM/AM broadcasts....
OP
eSGEe
Ferengi Ambassador of Trade
lol--- NO -- THERE IS sCHALLER-- AND cts AND dIMARZZIO GIBSON IS THE WOOD....AND TUNERS---- EVEN THE gIBSON FRETS ARE GONE LOL
OP
eSGEe
Ferengi Ambassador of Trade
yes-- it seems odd how some do it and some dont-- I dont guess its the pots-- as -- its a PCB board....cant change those and I didnt change those--
like I say -- I dont KNOW exactly WHY they do it-- just glad the shielding fixed it---
HERE is a QUIRKY thought ---
MAYBE the crappy plastic ground connector on the PCB -- that fell apart under my thumb.............wasnt "grounding" everything properly.....and the only thing I REALLY needed to do was break it and SOLDER the ground to the lug?
like I say -- I dont KNOW exactly WHY they do it-- just glad the shielding fixed it---
HERE is a QUIRKY thought ---
MAYBE the crappy plastic ground connector on the PCB -- that fell apart under my thumb.............wasnt "grounding" everything properly.....and the only thing I REALLY needed to do was break it and SOLDER the ground to the lug?