RADIOACTIVE MAN????????

[TIMBO]

Hi guy's, Spent all day yesterday trying to stop the buzz.Googled "Buzz stops when touching the guitar strings" and got mixed results, some say poor grounding of guitar and amp, some nature of the beast, more shielding, house wiring,dimmer switches and motors,computers.Tried everything i could think of and was left pretty pissed off  I have not tried using amp at another location as i do not do sell out concerts (bedroom only)
The buzz is ok at about "3" on the vol and PPIMV but anything above that it takes over  (unless touching the strings)
The buzz also has an intermittent louder buzz at times ??
I tried grounding the input at different at places but still the same ??

The one comment on the net was that " when touching the strings our body is not grounding the guitar BUT the guitar is grounding our body" WTF 

So when trying almost everything i put down the guitar (while still plugged in) and proceeded to tinker with the amp and found that when i touched the chassis the buzz DID NOT go away as it did before?
When picking up the guitar the buzz got louder as i held it closer to my body (effecting the electronics cavities the most) and i even asked the wife to do the same, with the same result of the buzz going away when touching the strings?????? 

I hit a wall when building the Plexi Gain 20 thinking that the HI GAIN amp was a bit beyond my build abilities but i 've got believe that the BUZZ/HUM that i could not remove is dew to my RADIOACTIVITY 

So now what do i do.Thanks

[Madison]

I recently had all my amps start buzzing.
Totally pissed me off.
It was definitely a "WTF?" moment.
Must be some sort new interference put in around here.
I found that the only guitar that didn't buzz was one of my Strats.
I had shielded all the guitars but the Strat had been shielded with copper tape and the others with aluminum tape.
Did all the others in copper tape.
Lesson learned, happy now.
YMMV.
BTW, mobile phone in your pocket when playing=total havoc.

[P Batty]

When I was doing sound in the '70's I remember trying to hunt down a buzz in guitarist's set-up.  The guitar (1959 Gibson ES 345) and various amp/cable combinations worked fine- until he picked it up. We turned his amp a bit to minimize it, but never got rid of it. An electric personality?

[tubenit]

I'd say the bridge of your guitar is not properly grounded (possibly).

OR a solder joint inside the guitar is not good.

OR the shielding in the cavity is not good.

OR you have the ground on one of the pickups hooked up as hot.

OR the the jack on your guitar is not hooked up correctly.

OR the guitar cord (and maybe all of them that you tried) is not good.

Something outside the amp is causing it.  Stick with it til you find it.

With respect, Tubenit

[TIMBO]

Well, spent much of the day poking around and are a little closer to finding the problem. Tubenit guitars are all stock rigs and the wiring all checks out OK. I tried a few values for the cap on the vol pot and settled for 250p cap as the smaller caps made the les paul sound a little dark, this also helped with some of the buzz and i also changed the vol pot to 470k (also added a .022 cap between pin1 of V1 and the .002   cap as the vol pot was a little scratchy ) this now gives more control of the gain. This i think this could be part of the problem as i do think whatever interference the guitar is picking up (i'm not sure what you would call it) and because as you have said this amp is very TOUCH SENSITIVE so the buzz that might be normally be much quiter is ampilified dew to the amp sesitivity.
Does this make any sense 

I find that the buzz is at an acceptable level when the Vol and PPIMV are at about "5" this is a good level for what i require anyway.So having 6L6 for the power tubes is a bit of over kill so i was thinking of changing them for 6V6s.
These are my node voltages :-
Pre A - 454v
A - 427v
B - 409v
C - 272v
D - 254v
E - 228v
Cathode Resistor - 430 ohms
I also found that the amp tends to feedback easily at the higher volume. Thoughts

[tubenit]

I don't know what to tell you. I would be terribly frustrated with what you are describing. I can't stand buzz or hum in an amps. It would annoy me to no end.

My Tweed Overdrive Special (5881's) and my Tweed BluezMeister (6V6) are both easily as quiet at idle as the Princeton Reverb (or Vibro Champ) that I used to own.

My TOS has no buzz or hum  and only slight hiss from the gain. It's amazingly quiet. The Carolina Overdrive Special I sold (similar amp to TOS but with active effects loop) was also very quiet.

The only I can tell you is that I'd stick with it until you get it resolved and not "settle" for the buzz. Wish I lived close to you so we could meet and I could help out.

The most puzzling and difficult trouble shooting that I've ever done was on the first amp I worked on. Took me about 6 weekends to find it. It was a resistor with a broken wire inside the enamel that would open and close with vibration by ONE note on the guitar neck. And chop sticking wouldn't reveal the problem.  UGH!!  Why only one note would create vibration needed to open the resistor is beyond me!

Having the buzz go away when you touch the strings of the guitar is your best clue.

Sure sounds like the bridge is not grounded properly?

With respect, Tubenit

[TIMBO]

Thanks for your encouragement T,I am still thinking it is not my guitars because all three are the same and amps are the same,even the SE.
PRR got me to check the guitar electronics and even the house neutral/ground and all checked out good. I'll through out some more info :-

Amp has no hum w/o lead plugged in clean @ full vol but some hum in OD @ full vol
No buzz with V1 pulled
Buzz bearable @ 5 on vol in clean and flicked to OD buzz changes tone and is quietier

I'll check the resistors for value and connection. Thanks

[tubenit]

Buzz bearable @ 5 on vol in clean and flicked to OD buzz changes tone and is quietier

Well, IF you like the tone and the volume works for you ...................

You can always measure the values on the volume pot and perhaps parallel a resistor so that "5" now becomes "8" with a paralleled resistor. That's more a "mental" thing but I can relate to it.   Hope that comments makes sense to you?

Can you check out one thing and post the answer, please?  With your guitar plugged in BUT not playing it ........ is there more buzz/hum with the guitar volume pot on "8" than on "10".

With respect, Tubenit

[tubenit]

Timbo,

IF you run out of things to try & feel desperate & willing to continue experimenting ............... maybe use an switchcraft NON-isolated input jack and Hoffman's grounding scheme.

I don't know what else it could be?

I will presume the guitar bridge is grounded and the guitar jack is wired correctly and not backwards.

with respect, Tubenit

[TIMBO]

Hi Tubenit, When i was checking out the LPs wiring i also changed the switchcraft socket to one of these long reach shielded type cause these are supposed to reduce hum http://uk.rs-online.com/web/p/jack-connectors/2988160/ but didn't change anything.

with guitar plugged in (not playing)no buzz with vol and tone @ 0
Vol @ 10 and tone @10 buzz
tone @0 and vol @ 9 buzz but vol turned to 10 no buzz

[PRR]

> vol @ 9 buzz but vol turned to 10 no buzz

The wire off the wiper of the Vol pot passes by some buzz source. Move it.

This lead normally has to be VERY short and direct.

[TIMBO]

Hey PRR,I bought this guitar in 1997 and i would have to say that last weekend was the first time i've had these covers off.I put these thin aluminium pieces under the covers with a wire to connected it to the ground but this did nothing.The vol wiper wire is red and as standard goes to the switch, so i guess its as short as its going to be.I am at a loss it what it could be cause all guitars and amps have the problem.

Some problems found on the nethttp://www.tdpri.com/forum/tele-technical/281392-hum-goes-up-volume-pot-goes-down.html

Thanks for your ongoing help 

[archaos]

You're right Timbo, we do are radioactive men at different levels  
Yet I've well-understood what kind of nightmare you're living...
I just dunno why, but I feel like stg could be wrong with the input jacks. You used isolated jacks didn't you (your pics are a bit blurry for me, sorry I'm as blind as a bat) ?
If so, how & where are they connected to the chassis ? I mean the ground-chassis connection must be done right at the very input of your amp, but I didn't notice that in your .sch files.
Furthermore, how did you make use of Merlin's grounding scheme ?

[TIMBO]

Hi archaos, I used insulated jacks and i tried many different ground connections for this jack and none helped the problem.At the moment it is connected to the buss ground that all preamp filters and pots are connected and then grounded at the PT bolt.

[archaos]

Hi archaos, I used insulated jacks and i tried many different ground connections for this jack and none helped the problem.At the moment it is connected to the buss ground that all preamp filters and pots are connected and then grounded at the PT bolt.

OK, things are clear for me now  
Did you try to connect it that way (see attached) ?

[TIMBO]

Thanks for your help archoas, but i am sad to say i did not help. My layout is based on your attached grounding but with only one ground connection to the chassis @ the input jack. I still feel that there is something else coming into play.

[archaos]

OK, so why not trying to connect it at the power output stage (with a hum-loop block network) as well as the very input jack ?
Have you ever tried your guitars with other amps elsewhere ?

[Tone Junkie]

Timbo did you try Geezers 100ohm ground referance trick on your switching circuit. Its what saved me on my last amp
Thanks Bill

[sluckey]

I don't think you'll find the problem is inside the amp. Your body acts like a big receiving antenna for all the electrical fields and noises in the air. When you hold your guitar close to your body the electrical noise is coupled to the pickups. Your body is not usually grounded or has a high resistance to earth ground, unless you're barefooted on a wet concrete slab. Your guitar strings are grounded. When you touch the strings you also give your body a better ground reference and the noise will decrease. This is normal. Some locations are worse than others. And with all the electrical noise makers these days , ie, wireless computer devices, cell phones, tvs, microwave ovens, fluorescent lighting, compact fluorescent lamps (CFL), etc., houses are increasingly noisier.

One thing to try would be to turn off every circuit breaker in your house except the one your amp is plugged into. This includes lighting and big breakers. Then unplug/turn off everything else that shares that circuit breaker. You only want the amp powered on. Does it still buzz? I know this is extreme, but it's only a test. And it may not provide conclusive results, especially if you live in an apartment building.

Maybe it would be easier to take your amp to another location. Maybe try two or three locations to see if the buzz changes. Or bring another similar amp into your house. You already have a couple buzzer amps. It just may be location, location, location.

[tubenit]

I don't think you'll find the problem is inside the amp. Your body acts like a big receiving antenna for all the electrical fields and noises in the air. When you hold your guitar close to your body the electrical noise is coupled to the pickups. Your body is not usually grounded or has a high resistance to earth ground, unless you're barefooted on a wet concrete slab. Your guitar strings are grounded. When you touch the strings you also give your body a better ground reference and the noise will decrease. This is normal. Some locations are worse than others. And with all the electrical noise makers these days , ie, wireless computer devices, cell phones, tvs, microwave ovens, fluorescent lighting, compact fluorescent lamps (CFL), etc., houses are increasingly noisier.

I am not clear how touching the strings creates a better ground reference?

So what is the solution????

Would it be possible to get something like one of the old TV antennae with a wire and alligator clip and then clip on to the amp chassis or something like that?

OR maybe have the ground to that one outlet be connected to a single metal rod pounded into the ground?

Just grasping for ideas here ..............

Tubenit

[Madison]

Crikey!
Copper shielding.
Don't settle for less.

[sluckey]

I am not clear how touching the strings creates a better ground reference?

A better ground reference for your body, not the guitar or amp. The strings will already have a good ground reference in a properly wired guitar, amp, and house. Consider this... You are wearing your best New Balance tennies. The rubber soles insulate your body from earth ground very well. You could stick a fork in the hot side of a wall outlet and never feel a thing. Kinda like the bird on the power line. You are totally ungrounded so no current flows. Now pick up your guitar and hold the strings. Repeat the fork trick. You'll probably say something nasty. The difference is that now your hand touching the strings has a path to earth ground. Current can now flow from the outlet, thru the fork, your body, your other hand, the strings, the guitar cable, the amp chassis, the green wire in your power cord, all the way back to your main entrance panel where you'll find the green ground wire is connected to the white neutral wire (other side of the 120VAC source). So, touching the strings provides a very good ground reference for your body. Once your body has a good ground, it now becomes a big resistor rather than an insulator. This resistance provides a load for the electrical noise that your body picked up from the air and will decrease that electrical noise.

You really don't have to do the fork thing. Get a friend to help!  

So what is the solution????

Eliminate the source(s) of the electrical interference in the air. Probably impractical. Maybe impossible. But the first step is to identify what the real source of the buzz is. I think the source is radiated noise based on Timbo's statement that the buzz is not present until he holds the guitar close to his body. The amp does not buzz even with the guitar plugged in unless he (or his wife) is holding it. It should be fairly easy to determine if the buzz is actually radiated, but it will likely involve taking the amp across town.

If the buzz is radiated, then no amount of grounding will eliminate it. However, you could build a screen room to shield the player, guitar, and amp. A proper copper screen room will significantly reduce radiated electrical interference. Kinda impractical for a homeowner.

[TIMBO]

Sluckey, You are always a wealth of knowledge  And what you have posted i think you are spot on and at first i found it had to get my head around the idea that we emit an electric field. I can fully understand the concept that we are more like an antennae and passing noise onto the pups (i did notice with this build the pups are more sensitive to noise, when picking the pick may touch the pup and it produces a loud tap type noise).

My study/amp room has my computer that has a wireless connection and i had some internet problems about 3 months ago and had to relocate the router from another bedroom to the kitchen and i am thinking that this was about the same time i was building the Plexi gain 20 witch had the same buzz.

I will try some more things later.

[sluckey]

Don't forget. I could be full of it too!. 

But really. Before you go crazy, take the guitar and amp across town. Even if you find it's no better, well, at least now you'll know.

[tubenit]

Timbo,

The side wall of your control cavity has no shielding. That definitely can make a difference. And I am not sure the aluminum will work as well as the copper tape?

The picture Madison posted of the copper tape is what my home made Tele control cavities look like.  Stewart McDonald as well as other places sell the copper tape.

With respect, Tubenit

[TIMBO]

I had some time to day to eliminate another possible suspect the internet wireless connection and guess what, that wasn't it. I have a few things to finish on the head cab so i'll try to find some of this copper tape and line the guitar cavity as well the inside the head cab and then i can put chassis back into the cab and see if that helps.

Just throwing out another possibility:-

pups supper sensitive to external noises (tapping pups with pick comes through loud)
intermittent buzzing over top of buzz
intermittent popping
sometimes PAB switch pops when switched
I have the trim pot for the tone stack mounted on the front panel and when turned to 0 the tone pot becomes the volume and the vol pot does nothing.

  Thanks

[TIMBO]

Hi guys, The copper tape worked to some extent but there is still some buzz happening.I lined as much of the cavity as i could but it seems that when holding the guitar with the control cavity centred on my body the buzz is a lot quieter than it was and the same with the pup switch cavity.When holding the pups centred to my body the buzz is loud again and when pressing the guitar harder into my body the buzz gets much louder. I can confirm that it is the " RADIOACTIVE MAN " that is causing the BUZZ. i noticed that the wires that run from the pots to the pups switch and back are not shielded at all, so i might replace them with some shielded and would lining the pups cavity be the next thing as well?? Thanks

[kagliostro]

Have you checked the connections closely to the pickup ?

try to dismount the pot unit from guitar than cover any surface with a thin galvanized iron sheet

(a can may be the source)

connect together the bottom to the walls of the cavity soldering

build a new top with the iron sheet (of adequate thickness) and solder a wire between top and bottom

remount the unit and ........... pry

Kagliostro

p.s.: Do not forget to cross your fingers when give it a try

[tubenit]

I have the trim pot for the tone stack mounted on the front panel and when turned to 0 the tone pot becomes the volume and the vol pot does nothing.

Are you referring to the bass trim pot?  IF so, something is not wired properly? And the PAB should not pop with the 22M resistor there.  Since the PAB and bass trim pot are connected ......... maybe something is going on there?

YIKES!  I discovered the layout I drew for the TOS 2CF was wrong on the PAB.  Attached is correct. This matches the schematic you have drawn. (Ignore the mid pot values, what you have is correct).

with respect, Tubenit

[Packerswin14]

Don't give up testing your home wiring.  Have you tried a filtered power supply?  I like the idea of killing all your breakers but one to see if that does it.  Ceiling fan, flourescent light, improper wiring could all create a field.  Could also be outside-- maybe a neighboring building has added something.  Did you get a new furnace or hot tub or something?  Maybe your home wiring is part of the problem, and a new local interference is being increased by something in your house, then your guitar is picking that up?

[TIMBO]

Hi guy's, Its taken me this long the get rid of this buzz and it only took moving house to fix it, all amps and guitars deathly quiet. 

[Zipslack]

That's a fairly radical solution...but with the price of copper, a shielded room like Sluckey suggested might have been just as expensive.  

On a side note, the company I worked for years ago doing EMI/RFI filters had two amazing screen rooms - 12'x12'x12' 1/8" thick copper with heavy doors with "finger" filter flanging.  Completely EMI/RFI free - but just sticking a dollar bill in the door before you closed it could allow radiated noise into the room from nearby radio stations - you could hear them over the test equipment.  Maybe we should all build wire screen into our walls/ceiling/floors and use aluminum-framed windows with metal screens.

I wonder if an static-discharge bracelet like we use for computer servicing would have helped.  It's basically a high-resistance mesh that attaches to your wrist or ankle with a cable that alligator-clips to a metal surface or ground to help bleed-off static charge.

[phsyconoodler]

I wonder if an static-discharge bracelet like we use for computer servicing would have helped.  It's basically a high-resistance mesh that attaches to your wrist or ankle with a cable that alligator-clips to a metal surface or ground to help bleed-off static charge.

I like that idea! I was going to suggest wearing an aluminum foil hat.But then you might pick up alien craft and get abducted.

 However,I have a 72 Deluxe tele with the widrange humbuckers that did the buzz and it was the guitar wiring.I replaced the wiring to the selector switch and used shielded wire grounded at the pots and it did the trick.It did not always buzz but now it doesn't at all.Anywhere.
  We all know that amps' lead dress can introduce noises,so why not guitar wiring lead dress?
I do have one customer that has buzz from nasty power on the telephone poles outside his house.There are three transformers close together and his buzz is permanent.Nothing he can do about it.
  My guitar is relatively quiet there but all his,even his Gibson's are noisy in his house.My new American special strat is not too bad but his is buzzy as hell.
  Maybe a combination of stuff?
If Timbos issue is gone with his move,then we may never know.