Noisy SG Static ?

[oldun]

Just finished my SG kit, I'm getting a lot of static as soon as the amp is switched on, but as soon as I touch the strings the static has gone, the bridge is earthed, so body capacitance eliminates this problem, I am wondering should I have shielded the wiring within the body ? using copper sheet, or alum sheet, would appreciate any ideas.

[kiteman]

That most likely will help. What SG kit was it?

[oldun]

That most likely will help. What SG kit was it?

Kit unknown, almost certainly made in China as I got it off Ebay at a good price. Well I just tried it thru my valve / tube amp and no problem, perfectly quiet, it just does'nt like the Vox solid state amp, I should have tried this before posting, the interesting thing is my Strat copy is completely noise free with either amp, anyhow thanks for your reply Kiteman.

[kiteman]

You're welcome and that is unusual. It seems that your Vox is the one with the grounding issue. Does it have a 3 prong or polarized power plug? You can try another power outlet.

[oldun]

You're welcome and that is unusual. It seems that your Vox is the one with the grounding issue. Does it have a 3 prong or polarized power plug? You can try another power outlet.

The Vox is only a 2 prong plug, it's a switchmode PSU as it only needs to supply enough for 5 watts, I would tend to agree with you but, the puzzle is why is the Strat completely noiseless with either amp, either the Vox solid state or Epiphone tube / valve, the easy fix is just use the tube/valve amp for the SG and all is ok, but these things are intriquing, I know a big percentage of electrical problems come back to a bad earth return, I have checked my SG bridge with my ohm meter, the only thing I didn't do as I said was no shielding of the body cavities etc. I had a trailer once that would send the turning lights into a frenzy when you applied the brakes, this was simply fixed by running a separate earth wire, the main wiring harness earth was losing continuity thru the trailer coupling. Next time I replace the strings on the Strat I'll see if they used any shielding in the cavities, I some how doubt it on a Strat copy, but you never know. Well I have just tried something here on the Vox, I connected it up to a DC power supply which it's designed for also, and would you believe it, now using the AC switchmode PSU absolutely no noise, I'll call it quits here and head off to bed before it changes again.

[Duffy]

There shouldn't be any static coming from the SG.

When you touch the strings you are grounding out the electronic system of the guitar with your hand. This is a strong indication that you have an internal grounding problem with your SG's wiring.

Did you run "all" of your ground wires to the top of the same pot? This is the preferred method and avoids noise producing "ground loops" from too many different grounds.

Also, did you run a ground wire from the top of the ground wires pot to a soldered on loop at the end of the ground wire and screw it into the wood of the guitar with a "conductive" wood screw?

You might try running another ground wire from the top of the pot all the ground wires are soldered to, to a soldered on loop at the end of the ground wire and secure it to the wooden body of the guitar with a conductive wood screw. This additional ground might be sufficient to ground everything out just like you are doing when you touch the strings.

Make sure all the grounds, including the grounds from both of the pickups are going to the top of the same pot and a ground wire goes to the body from there. Sounds like a weak ground and I would look to see if both pickup ground wires are going to the same pot and that a ground wire goes from there to a wood screw. You might have a different ground that is just pushing up against shielded paint or something; or just not making sufficient contact with ground.

My electric fence has three copper ground rods driven into the ground in a row and the ground wire daisey chained to all three grounding rods as the factory recommended method of grounding the electric fence. This helps ensure a strong current flowing thru the electric fence wire.

I would guess that the grounding problem is within the guitar's electrical system and that you are grounding it out when you touch the strings, rather than the guitar being adequately grounded within its electronic system.

This should be an easy fix but will require that you take the control covers off and examine all the ground wire paths for solid solder joints and everything going where it should.

Note:

Also, if you have coil splitting capable pickups but are not wiring your guitar for coil splitting, you will have two extra wires coming from each pickup. You will get noise if you don't twist these two wires together and then preferably solder them together and tape them off with electrical tape. I didn't know about this and wired up a guitar and had similar noise to yours. When I found out what to do and twisted those wires together and soldered them the noise went away and I had some real nice real powerful humbuckers to enjoy.

[oldun]

[QUOTE=Duffy]There shouldn't be any static coming from the SG.

When you touch the strings you are grounding out the electronic system of the guitar with your hand. This is a strong indication that you have an internal grounding problem with your SG's wiring.

Thank you Duffy for your detailed reply and time taken, all much appreciated, I will print this out for any future reference.
What is puzzling me is if I use the Vox solid state amp running a battery DC power I have no static from the SG, it's perfect with fantastic sustain, it's also perfect thru my Tube / valve amp, so now I have come to the conclusion that it's the Vox amp, it seems to be one of those intermittent problems, because at times if I firstly run dc power, then switched to AC power the amp and SG were perfect, but just tried again and now the SG is still noisy even after switching from DC to AC power, my Strat copy has always been quiet with either amp, this is why I thought the SG was the problem, but now I have the same problem with both guitars when using the Vox amp on AC power only, I'll check with the shop where purchased and see what they have to say. Many thanks again.

[Duffy]

I love the SG guitar and have three SG types: two Epiphone SG's and an amazingly great sounding inexpensive LTD Viper 50 SG copy.

Sounds like yours is silent.

Sounds like the amp has a grounding problem with the power supply or something. Is this a Vox DA5, great little amp?

Take your SG to the guitar shop and play it thru a few other amps. Tell the tech there (go to a place that has one) what is going on. Bring the Vox. Advice is usually cheap. If it is the Vox DA5 have him try it with a different power supply wall plug.

Also, to eliminate some of the obvious, take you Vox and guitar into another room on a different circuit breaker if possible, and try it there. See if there is any difference in the static. The wiring in your house in that room might be messed up or not grounded right, or even just that one receptacle might not be grounded right. Also, the wall plug in power supply for the Vox might be picking up interference from something in its area.

Is the static constant or just when you play? Is the static present when you unplug the guitar from the amp? If the static is there when you unplug then it is definitely not the guitar. Possibly spray some Deoxit into the power supply jack and push the jack in and out a few times, maybe there is some slight corrosion there.

This definitely sounds like a ground problem somewhere.

If the static is still there when you go to a different area of the house or garage and play the SG into the Vox, you know the problem is persistent and is within the guitar/amp system only when plugged into AC wall current. Armed with this knowledge, you should be able to bring the amp and guitar to a guitar tech and he will be able to immediately know what the problem is, or have a very good idea of what is wrong and a plan to test his theory. Play the SG into a few different amps while you are there to try and get some static.

Another thing: your guitar cable may be the cause of the static. Try a couple other cables. You need to replace your cables periodically because they short out from twisting, etc. Get as good a cable as you can afford. Buy a can of Deoxit from a guitar shop. It is an electrical contact cleaner made for guitars and amps. Spray it into amp jacks and work the cable plug into and out of the jack after spraying the deoxit in there, a few times. It works great to spray into your potentiometers and tone and volume knobs on your guitar, plus the cable jack on your guitar and then push the cable in and out several times. Also spray it into your switch - take the control cover off the switch cavity if you need to to get to the inside of the switch.

Check the real obvious stuff without delay - like moving to a different outlet on the wall; using a new or some different guitar cables; spraying deoxit into the cable jacks and the power supply connector jack on the back of the amp.

If the static is there with the strat too, then it is a problem with the Vox or the power supply between the wall and the amp, or a problem with the outlet or wiring in the room. Don' t take anything for granted. Makes sure it is the amp and not all your amps plugged into the same outlet. Makes sure it isn' t the SG. Double check everything.

Get a professionals advice, preferably with guitar and amp in hand.

Hope this info helps. Sounds like your problem is fixable, just not diagnosed exactly yet.

[wingsdad]

Static? As in a crackling sound? Does it happen in all pickup positions? Does it happen if you don't touch the pickguard?

I had this problem with an Asian import guitar, but with single coil pickups, when I had it in the 'both' (middle) mode, if I touched the pickguard. If I managed to keep my fingers from contacting the pg, no static. Tech suspected it had something to do with the pots. Cheap? Bad wires?

Shield the pg? Nope. Already was.

Don't really know. But I wasn't up for screwing around changing this and that, hit and miss. The tech's simple solution was to rub a fabric softener dryer sheet on the pickguard. Just like those things take static cling out of clothes, it eliminated the static.

It made the guitar case smell nice, too.

[kiteman]

[QUOTE=Duffy]There shouldn't be any static coming from the SG.

When you touch the strings you are grounding out the electronic system of the guitar with your hand. This is a strong indication that you have an internal grounding problem with your SG's wiring.

Thank you Duffy for your detailed reply and time taken, all much appreciated, I will print this out for any future reference.
What is puzzling me is if I use the Vox solid state amp running a battery DC power I have no static from the SG, it's perfect with fantastic sustain, it's also perfect thru my Tube / valve amp, so now I have come to the conclusion that it's the Vox amp, it seems to be one of those intermittent problems, because at times if I firstly run dc power, then switched to AC power the amp and SG were perfect, but just tried again and now the SG is still noisy even after switching from DC to AC power, my Strat copy has always been quiet with either amp, this is why I thought the SG was the problem, but now I have the same problem with both guitars when using the Vox amp on AC power only, I'll check with the shop where purchased and see what they have to say. Many thanks again.

And still under DC you have no static?

This indicates the problem is with the power supply of the amp. It'll have a rectifier circuit and the (filter) cap is probably leaking AC IMO.

[oldun]

[QUOTE=Duffy]I love the SG guitar and have three SG types: two Epiphone SG's and an amazingly great sounding inexpensive LTD Viper 50 SG copy.

Sounds like yours is silent.

Sounds like the amp has a grounding problem with the power supply or something. Is this a Vox DA5, great little amp?

Yes it's the Vox DA5, I usually stay with reverb and clean 1 pos, even on 1/2 watt you could damage your hearing over time. I have just tried different wall sockets, no improvement, changed cables I have 3 of, the better quality heavier cable did make a bit of improvement but not acceptable, no change with the other shorter cables, still very noisy, changed the PSU AC, I had a spare, no improvement, but for some reason I played around with the Vox controls and found by turning my Vox tone control down about half way no noise, but any where between half and full treble it's very noisy, ( Static and hum ). Static is not there as long as you play or simply make contact with any metal part on the guitar, although there are a lot of confusing issues I'm convinced it is the Vox. BTW I nearly bought a Viper SG but the idea of building a kit appealed, then this kit came up on Ebay, and you know the rest, the main part that worried me a bit was gluing the neck, but all went well using the proper glue, changed the strings to D' Addario's. Just in case I'm going crazy I tried the SG on the Tube amp again and no problem all quiet, then Strat on the Vox same problem static, I'm sure the Jury can only come to one conclusion, the Vox is guilty.
Anyhow thanks very much again Duffy for your input and time spent here.

[oldun]

Static? As in a crackling sound? Does it happen in all pickup positions? Does it happen if you don't touch the pickguard?

I had this problem with an Asian import guitar, but with single coil pickups, when I had it in the 'both' (middle) mode, if I touched the pickguard. If I managed to keep my fingers from contacting the pg, no static. Tech suspected it had something to do with the pots. Cheap? Bad wires?

Shield the pg? Nope. Already was.

Don't really know. But I wasn't up for screwing around changing this and that, hit and miss. The tech's simple solution was to rub a fabric softener dryer sheet on the pickguard. Just like those things take static cling out of clothes, it eliminated the static.

It made the guitar case smell nice, too.

Well thanks Wingsdad, I've heard the saying "runs on the smell of an oily rag ", but that cure beats that, I'll keep that one also for future reference, the funny thing is at this stage I have'nt fitted the pickguard, so that's the only offending article I don't have, but thanks also for your input on this, it might well be one I need in the future, BTW I put baby oil on my rosewood fretboard, I now probably have the sweetest smelling fretboard.

[oldun]

[QUOTE=oldun]

And still under DC you have no static?

This indicates the problem is with the power supply of the amp. It'll have a rectifier circuit and the (filter) cap is probably leaking AC IMO.


I reckon you might be on the money Kiteman, certainly something at least similar, definitley no static on DC power.

[Duffy]

On my DA5 I had to take it apart and expose the circuit board where the power supply jack plugs into the amp. The jack is integrated plastic and built onto the circuit board. The plastic jack had applied pressure to the board and there was a hairline crack in one of the solder traces going from the jack, on the circuit board. Very hard to see and almost microscopic, but visible.

Unit would not work off wall current. I carefully soldered over the crack and completed the circuit. It corrected the problem and works perfect now. You could have a similar crack in your power supply circuit on the circuit board right by the plastic plug that is mounte on the circuit board, where the power supply plugs in. This could cause a harsh cutting in and out static sound switching between AC and DC current. I would check this part of the circuit board where the jack plug attaches to the board. The power supply jack exerts force on the jack and since it is mounted directly to the circuit board I could have cracked the solder traces on the board at that stress point, like it did on mine.

Try grabbing the power supply plug where it plugs into the back of the amp and moving it around while you are playing and see if you get static out of it. That could be your weak point and source of static. You might even want to take the batteries out and wobble the power supply jack around on the back of the amp and see if you get static or cutting in and out of sound when hitting a string. That jack might not be grounded because of a broken solder trace or other problem at this very weak point. That jack input point is subject to a lot of jerking around and moving around and may have cracked the very fragile solder traces or trace on the circuit board, which is not flexible.

It is worth checking out. I only had to remove a few screws to access the circuit board where the jack plugs in. Located a crack in a trace by the plastic jack receptacle and soldered it carefully with a pencil tip soldering iron and it works great now and I protect the power input jack now, being very careful not to stress this point.

[oldun]

[QUOTE=Duffy]On my DA5 I had to take it apart and expose the circuit board where the power supply jack plugs into the amp. The jack is integrated plastic and built onto the circuit board. The plastic jack had applied pressure to the board and there was a hairline crack in one of the solder traces going from the jack, on the circuit board. Very hard to see and almost microscopic, but visible.

Just tried the AC jack for movement but made no difference to the static can you remember if removing only that upper back panel gives me access to both sides of the circuit board, I've got a feeling my problem might be different to the one you had but it was worth a try, I'm getting a very loud AC hum and I'm still getting the Static, but now with slight variations in loudness, I have found by reducing the gain to quarter power I can run the tone control to max now, and also by varying the master control I can re-adjust the other 2 pots to different positions with acceptable levels, I think I'm at the point of making 2 choices, 1 simply reduce the output via playing with the pot adjustments, if it gets worse back to the music shop, it's out of warranty by about 6 months, even reducing the output it's still plenty loud enough for me, your info on that Jack via circuit board will be a good one to remember, it sounds like a weak link and I'm sure to get it at some stage I'm sure, so Duffy thanks again.

[kiteman]

That AC hum is pretty indicative of the power supply problem.

[oldun]

[QUOTE=kiteman]That AC hum is pretty indicative of the power supply problem.[/QUOTE

yes it's looking like your previous prognosis Kiteman, but all the other responses are valuable for future reference also, been some interesting ideas.
Thanks again.

[Duffy]

Oldun,

Have you identified the source of the problem yet?

Have you taken it to a guitar shop that sells these and tried substituting in a power supply from a new one and seeing if this corrects the problem?

It would be interesting to know what, exactly, the problem turned out to be.

It is one of those vague, hard to isolate the source of, type of problems.

[oldun]

Oldun,

Have you identified the source of the problem yet?

Have you taken it to a guitar shop that sells these and tried substituting in a power supply from a new one and seeing if this corrects the problem?

It would be interesting to know what, exactly, the problem turned out to be.

It is one of those vague, hard to isolate the source of, type of problems.

I phoned the shop where I bought the amp, they said they have never had a problem with the DA5, maybe fact and maybe not, could be just a automatic trained response to customer problems, anyway they no longer carry out repairs and gave me the details of who they now recommend, these other people charge $50 dollars to quote, plus of course the repair itself, if you don't go ahead it costs you $50, considering I can replace it for $190 you would'nt want to spend too much on repairs, and the fact it is still usable I'll wait until it gets worse or stops, then it's either a replacement or repair, can't find a circuit diagram for it, might consider having a look at it myself it it gets a lot worse, I'll let to know what happens when I make the decision, and yes it's a very vague one and confusing as other controls have different effects on the main problem, and to give a tech the go ahead today it's very easy to get at least a $100 dollar repair bill.
Duffy, it's not the power supply itself I tried another one known to be good, made no difference.

[Duffy]

Yeah. Spend a hundred on it and not even come close to getting it repaired. I would probably just plan on getting a new one. They are a really nice amp to have, batteries and all.

Vox has this nice new amp out, the 20+ that is less than two hundred and would be money well spent. Has a tube in it. Very nice. Stomps on the DA5 except for the fact that the DA5 rolls with batteries.

A DA5 is really a nice amp to have around. There is no substitute for a good DA5 when it comes to camping, going to the park, etc.

You must live in a distant part, Oldun, around here they sell for 139 US at the big online places.

[oldun]

Yeah. Spend a hundred on it and not even come close to getting it repaired. I would probably just plan on getting a new one. They are a really nice amp to have, batteries and all.

Vox has this nice new amp out, the 20+ that is less than two hundred and would be money well spent. Has a tube in it. Very nice. Stomps on the DA5 except for the fact that the DA5 rolls with batteries.

A DA5 is really a nice amp to have around. There is no substitute for a good DA5 when it comes to camping, going to the park, etc.

You must live in a distant part, Oldun, around here they sell for 139 US at the big online places.

I'm in Australia Duffy, so yes that would be distant from you, I like the DA5's dc power ability, real handy when we get power failures here, since our power supply is now by private companies, and lacking maintenance procedures, power drop outs can last for a few hours several times a year, I usually keep one of those 7amp hour gel cell batteries charged, and have made a connector up to use my cordless power drill batteries or that gel cell battery for the DA5 if needed. The 20+ sounds interesting, although I do have the Epiphone tube amp.

[Duffy]

Oldun, I had no idea you were so far away from here. I don't know what the cost to you means, so many variables unknown to me.

I would avoid the hundred repair cost though.

I thought you mentioned you were looking to get another amp. With the Epiphone you are covered there.

I have always been skeptical of these newer highly computerized and extremely complicated amps, like Vox is fond of making. Finding someone educated enough to diagnose and repair one of the more complicated of these has to be difficult. People with that level of electronic education typically are not working in guitar shops. Plus, the technology is rapidly changing, with new circuits in the amps, and complicated amp modeling and effects processing, etc.

The DA5 is just a simple version of one of these incredibly complicated amps, and has its own difficult to diagnose areas, I'm sure, despite its small size.

I like to try to keep my amp choices fairly simple designs, but even then I probably have more complicated amps than I think I do.

I would like to think that amps like the Hot Rod Deluxe and AC15c1 will be able to be fixed well into the future by ordinary amp techs; but when it comes to things like the VT100 and 20+ I think things are probably at a level of complexity that few are prepared to effectively work on them.

Peavey Vypyrs, Vox Chromies, Cubes, and other highly complicated amps have to be really dificult to get fixed when things other than simple fixes go wrong with them, and there are plenty of things that can potentially go wrong with those highly complicated amps.

They are really neat amps capable of some unheard of things, but with all of that at your fingertips, comes a cost or costs.

There probably is a simple solution to your amps problem, it's just that it hasn't been figured out yet, and we can't just look at it, probably, and see exactly what the problem is.

At least it is working half way decent. Good luck with it.

[kiteman]

If you decide to look at your amp maybe you can do some simple tests. Look at the big caps that's near the power transformer and tap on them. The bad one will probably make noises from the tapping. Those caps will have diodes next to them.

The power transformer convert the house current to AC power for the amp. The diodes convert the AC power to DC power and the caps smooth out the ripples on the DC power operating the amp.

[oldun]

[QUOTE=Duffy]Oldun, I had no idea you were so far away from here. I don't know what the cost to you means, so many variables unknown to me.

I would avoid the hundred repair cost though.

I thought you mentioned you were looking to get another amp. With the Epiphone you are covered there.

I have always been skeptical of these newer highly computerized and extremely complicated amps, like Vox is fond of making.

Duffy, I probably mentioned something like before I spent $100 or plus on my Vox, I would be thinking more in line with replacing it, I would be more confident in working on the Epiphone as I have the circuit for it and there's so much info for it on the net, but I agree these amps today are getting so sophisticated they're getting like our cars, and with my Ford Futura all I can do is refuel, and top up the windscreen washer reservoir, the rest has to be put on a diagnositic computer at the Ford dealer with around a $100 plus per hour, I think if I need to ever go for another amp I would consider another basic tube amp, if you want effects maybe consider the outboard rigs, at least when they play up you should still have your basic tube amp, and I have to say there is a difference in tone from tubes, but that Vox gets so close.

[oldun]

If you decide to look at your amp maybe you can do some simple tests. Look at the big caps that's near the power transformer and tap on them. The bad one will probably make noises from the tapping. Those caps will have diodes next to them.

The power transformer convert the house current to AC power for the amp. The diodes convert the AC power to DC power and the caps smooth out the ripples on the DC power operating the amp.


Yes Kiteman, if it gets to the stage where something just has to be done I'll have a poke around it myself, thinking about your explanation I suppose even the diodes could be the problem, so thanks for these tips they are really helpful.

[kiteman]

Yes, the diodes can leak too but unlikely.

[oldun]

Yes, the diodes can leak too but unlikely.


Ok thanks Kiteman.