noise from guitar cord

[mat]

While tapping on the guitar cord (not the tip) that is plugged in to amp (guitar not plugged) I get noise from speakers. Where should I look for the problem ?

Thanks,

[Structo]

The cord?

Seriously, some shielded cables are more microphonic than others.

That is an area of concern for high end cable manufacturers.
A lot of them now employ a layer of conductive plastic over the center conductor insulator to prevent such noises.
You just have to remember to trim that back when fitting a plug to the cable.

[PlinytheWelder]

Yep, you have a microphonic cord...

[selloutrr]

meter the instrument cable (ohms)

tip to tip: 0.01 = 15' / 0.03 = 25' / 0.07 = 50'
shield to shield = 0.01
tip to shield = No Contact

if you have anything over the above values resolder and test again. If the measurement is still high or over 1ohm throw it away or start cutting it back, resolder the connection and test again. look for crimps and points of stress in the wiring.

Some cables are made with poor insolation and or thin shielding.
The best instrument cable is a braided shield.
You do get what you pay for in cable. Althought with that said, Monster cable and other "pro line" guitar center sales are a joke. Canari, Beldon, and Mogami quad star is what the professionals use priced under $2.50 a foot. You also want a quality connector Switchcraft or Neutrik. the cheaper knock offs use cardboard spacers to seperate the tip and sleeve which break down and short out.

[Structo]

Even the lower priced Mogami cable works well in most situations.
The pros have been using it for years.

I buy mine at Redco.

[mat]

Thanks for the answers. I'll measure the cable tomorrow. It is a Fender vintage style cable. DOH! All I was thinking was that there is something wrong with the amp...

[Dai H.]

if the gtr. isn't connected (open, non-shorted input), isn't that making the amp more susceptible to noise? I'm thinking electrostatic(capacitive).

[mat]

if the gtr. isn't connected (open, non-shorted input), isn't that making the amp more susceptible to noise? I'm thinking electrostatic(capacitive).

I resoldered the 2 fender cords and got following ohm readings:

1. cord: (tip to tip/shield to shield)
before 01,1/00,2
after 00,3/00,2

2. cord:
before 00,4/04,0 !
after 00,3/00,4

Tried to tap the cord with guitar unplugged and I still get quite loud pop noise when snapping the cable. With guitar connected and guitar volume at zero - no pop. Guitar volume full - slight pop. Guitar unplugged - loud pop.

Seems like it is the amp after all ?

[Dai H.]

I'm not really sure what the goal is here? With no gtr. connected, isn't the lead going to be sort of a "noise probe"? As far as I've read, there do seem to be differences in susceptibility to capacitive noise (that can come from tapping, stepping on, etc. the cable) with different cables but I would think that if you buy a purpose built cable (gtr. cable, whatever), then this shouldn't be a problem.

[Structo]

Yeah, not sure it is valid when the cord is unplugged since that is not it's purpose, but rather how it sounds and behaves when the guitar is connected to it, to the amp.

Are you saying that the resistance increased after you re-did the plug ends?

That is strange if so. Not sure what kind of cable Fender uses, but be sure that the inner conductor insulation does not have the black carbon coating near the end of the wire. This can short out or add resistance to the cable.
It must be trimmed back just a bit from the inner wire insulation.

I too used to think a guitar cord was a guitar cord.

Probably due to the gear craze at TGP I looked into better cables and bought a couple "higher end" cables from Lavacable.
It really was a day and night difference between what I had been using and the new cable which was a Sommer "The Spirit" cable.
Much more clarity and high end.

Basically you want to treat your guitar cable like part of the tone stack in a way since it behaves like a capacitor.
The lower it is in pf/ ft. the more highs it will pass on to the first stage.
This can be a double edged sword though, if your amp is already very bright, using a very low pf cord can seem to make the guitar too bright.

But for a darker sounding amp a low pf cable can really wake it up in a good way.

[mat]

Are you saying that the resistance increased after you re-did the plug ends?

As You can see on my previous post the resistance came down after resoldering the connections.

I don't know if anything is wrong, I just haven't noticed before that snapping on the cord could make such a noise. Also rubbing the cable makes a ehm, rubbing noise from the speaker.

[Structo]

Sorry, I guess I misunderstood your nomenclature.

[Tillydog]

Tried to tap the cord with guitar unplugged and I still get quite loud pop noise when snapping the cable. With guitar connected and guitar volume at zero - no pop. Guitar volume full - slight pop. Guitar unplugged - loud pop.

Seems like it is the amp after all ?

Nope, it's your cable - with the guitar volume down, the guitar pot is shorting the cable so you don't hear anything.

If you can't live with the 'pop' you get when the guitar is plugged in + volume up, you need to try a different cable. IMHO make up your own with decent quality microphone cable.

0.02p

[PlinytheWelder]

I make my own out of Canare wire. Others use Mogami. Both are very quiet...
Good cables don't have handling noise.

[mat]

I make my own out of Canare wire. Others use Mogami. Both are very quiet...
Good cables don't have handling noise.

Thanks for the tips. I have to source the cables I've done earlier from mic cable. I'll test them too.