Static Crackle When Touching Metal Guitar Parts

BillDL

This is something I am sure I haven't had before with a guitar, or perhaps I just haven't noticed it until now.  I have a SSS Strat copy I haven't played for a while that, when plugged into my Boss Dual Cube LX, makes a "static" crackle through the amp each time my finger makes contact with any and all of the metal parts including strings, and gets louder the higher the amp is turned up.  The guitar is actually quite a quiet one despite being unshielded, but does have the expected low level single coil hum that almost goes away when I touch metal parts.  That's quite normal though?

I haven't tested all my guitars through this amp, but so far:

1. This is the only guitar I have that crackles like this with that same amp.

2. This guitar does not do the same when plugged into a directly mains powered amp.

3. I have swapped cables just in case that is a contributory factor.

4. I haven't yet tried the amp with batteries as I don't have 8 x AA ones in the house right now.

5. I tested the power supply adapter with the amp on a different circuit and different sockets in the house and it makes no difference.

I'm using the supplied Roland 9v inline "brick" type power supply adapter with detachable 3-pin supply lead.  I haven't tried the amp with other power supplies yet, but I have tested the supplied power supply with a Boss Katana Mini and the guitar doesn't crackle when played through it.  The only other portable amp I have that use a power supply adapter is a Bogner Ecstacy Mini Amp Head (24v adapter), and that doesn't exhibit the same behaviour with this amp.  I think this was the first time I have played this guitar through the dual cube amp since I bought the amp.

I'll do some more exhaustive testing for elimination later (while I also troubleshoot a Levinson Blade with an odd earthing issue where the hum increases when I touch the bridge and strings but not the other metal parts), but I was curious to know whether anybody else had experienced this effect with any guitars and amps.

elstoof

Does the main plug on the adaptor have an actual earth pin or is it only L-N with a dummy Earth?

ICBM

elstoof said:

Does the main plug on the adaptor have an actual earth pin or is it only L-N with a dummy Earth?

It won't matter - the Roland Cube series power supplies don't connect the earth to the DC ground anyway.

The static noise is probably just a consequence of lack of shielding combined with a non-earthed amp.

BillDL

elstoof said:

Does the main plug on the adaptor have an actual earth pin or is it only L-N with a dummy Earth?

ICBM said:

It won't matter - the Roland Cube series power supplies don't connect the earth to the DC ground anyway.

The static noise is probably just a consequence of lack of shielding combined with a non-earthed amp.

Thank you gents.

It's the type with the 3-pin plug to a 2-connector shaver / figure-of-eight / infinity sign / shotgun / IEC C7 connector at the other end that plugs into the brick power adapter, so it's a dummy unused earth pin on the mains plug.

I was doing some switching and swapping of guitars and amps today at higher gain and volume and I have discovered that the affected guitar is NOT the only one that makes the static crackle on finger/hand contact.  Other guitars also do it on this amp, but to a MUCH lesser extent where it's only really audible and annoying at higher amp gain/volume.  This guitar is by far the worst, and I discovered just a couple of hours ago that it also makes the crackles when plugged into directly mains powered amps, but to a far lesser extent where it isn't annoying or even obvious.

One other thing I discovered is that it is much worse when I am lying on my couch with my feet up and my elbow rubbing against my shirt and cushions.  When I put my feet down and take off my socks, even on the carpet, the crackling sound drops to a very quiet and far less annoying level.  When played through a direct mains supplied amp with me standing on the floor the crackles are very quiet and almost inaudible even with the amp turned up, whereas when I lie on the couch again they get louder.

I had only restrung the guitar just before I realised this issue (locking tuners with no slack to loosen), so it will be a while before I will be removing the scratchplate to see about shielding, but I think the issue is a combination of the hard "poly" finish and static build up on the guitar and my body (hairy arms against synthetic cushions, etc) not properly discharging.

Kittyfrisk

^ I have found that rubbing body parts against synthetic cushions etc. does definitely inhibit a satisfactory static discharge.
Saves ages cleaning up though...