Telecaster Hum issue with Amp modeller and amp.

Jetsam1 · April 17

Hi, received a POD HD Bean and was having issues with really loud high pitched hum (I did some checking and there is a hum programmed in for realism on the amp models but this was not it). I tried moving it around the house and with different cables and guitars and with another power supply. Narrowed it down to the Telecaster itself. It also seem to hum on the Peavey as well but this is much less noticeable.

The guitar is a 2007 US Fender Telecaster with SCN single coils and the S1 circuit. As these are supposed to be noiseless pickups I was quite surprised. This behaviour is new as although I have not really played any guitar for a few months it didn't do this in the past. I haven't opened it up yet as I wouldn't be sure what to look out for and check. I have a soldering iron......

Any ideas? Wiring starting to get old? Jack earth maybe?

BillDL · April 17

I am not expert enough to suggest any remedies, but it will be helpful for the electronics experts to know a couple of things for the purposes of elimination.

Does it stop humming, or does it change the sound or intensity of the humming, when you touch the strings, control plate and other metal parts?

Is the humming different in the different pickup selector positions?

Does the hum stop or lessen if you move the cable plug around in the socket?

stickyfiddle · April 17

BillDL said:

I am not expert enough to suggest any remedies, but it will be helpful for the electronics experts to know a couple of things for the purposes of elimination.

Does it stop humming, or does it change the sound or intensity of the humming, when you touch the strings, control plate and other metal parts?

Is the humming different in the different pickup selector positions?

Does the hum stop or lessen if you move the cable plug around in the socket?

To add to these, do you have dimmer switches on your lights? If so, does is still hum with all the lights off?

ICBM · April 17

Does it stop if you turn the guitar volume right down?

My best guess at this point is the contact to the shielding paint in the body cavity, but will need more info to narrow it down.

Funkfingers · April 17

stickyfiddle said:
do you have dimmer switches on your lights? If so, does is still hum with all the lights off?

Similarly, have you purchased new "white goods" domestic appliances in recent months? Have you moved to a new location?

Jetsam1 said:

2007 US Fender Telecaster with SCN single coils and the S1 circuit.

That makes it a Deluxe American model. The bridge saddles are machined from solid stainless steel. Unfortunately, stainless steel is a poor electrical conductor. This limits its usefulness in the grounding path for the strings.

An S-1 switch that still works after seventeen years has fared very well.

Inspect and, if necessary, refresh the solder joints on the underside of each pickup.

Jetsam1 · April 17

Hi, stops when I touch the strings or anything metal on the guitar, including the metal jack sockets when connected. It does change when the guitar volume is lowered. All pickup selections are the same.

No dimmer switches in the house and I have tried with the POD plugged into other sockets in other rooms and the response is identical. I also tried two Strats one with standard SCs and one with SD YJMs and also an Ibanez with twin humbuckers and no particular issues from them. The Mex Std Strat had a little hum but I expect that and no more than standard SC behaviour.

timmypix · April 17

If it's stopping when you're touching the strings or anything metal on the guitar, then it's a grounding issue and you're becoming the ground when you touch metal. Have a look in the cavity to see if the ground wire's come loose from any of the components or from the cavity shielding.

Jetsam1 · April 17

Opened up the control area, all wires are firmly connected as far as I can tell. No obvious breaks either. However, all I can see is paint in there. I do not think this is shielded at all. Shielding should be obvious I think?

ICBM · April 17

This is definitely a (lack of) cavity shielding issue.

The shielding is paint under the colour coat, it’s difficult to see. Somewhere, there should be a terminal screwed to the cavity floor - this connects to the paint under the finish. Try screwing it down tighter, or undo it, scrape a little of the finish off around the hole, and refit it.

stickyfiddle · April 17

timmypix said:

If it's stopping when you're touching the strings or anything metal on the guitar, then it's a grounding issue and you're becoming the ground when you touch metal. Have a look in the cavity to see if the ground wire's come loose from any of the components or from the cavity shielding.

No - the opposite in fact.

If the metal wasn’t grounded then touching it wouldn’t make any difference. What happens when you touch the metal bits is you are also grounded, and your body acts as a shield, picking up lots of the noise and helping it get to ground without going through the pickups

timmypix · April 17

stickyfiddle said:

timmypix said:

If it's stopping when you're touching the strings or anything metal on the guitar, then it's a grounding issue and you're becoming the ground when you touch metal. Have a look in the cavity to see if the ground wire's come loose from any of the components or from the cavity shielding.

No - the opposite in fact.

If the metal wasn’t grounded then touching it wouldn’t make any difference. What happens when you touch the metal bits is you are also grounded, and your body acts as a shield, picking up lots of the noise and helping it get to ground without going through the pickups

TIL!

ICBM · April 17

stickyfiddle said:

No - the opposite in fact.

If the metal wasn’t grounded then touching it wouldn’t make any difference. What happens when you touch the metal bits is you are also grounded, and your body acts as a shield, picking up lots of the noise and helping it get to ground without going through the pickups

It’s even more the opposite - if it was a bad ground somewhere, touching any metalwork before the break in the ground path would actually *increase* noise.

Jetsam1 · April 17

OK, took everything apart that I could find. Don't see any separate wires attached to the body, three wires going to each pickup. I tightened the jack socket and have restrung it.

After this the hum/static noise had got quieter. An interesting thing is that taking the tone control all the way down gets rid of all hum and bringing it back up after half way it comes back as per the normal sound. Putting any pressure on the tone control crates a static sound so wondering if maybe there is a problem there?

Guitar is as it came out the shop in 2007, nothing other than strings has been changed ever.

I am supposed to be starting the deep clean of the kitchen!

BillDL · April 17

The kitchen can wait. Fixing your guitar is far more important

Find a piece of wire or metal long enough to go from the jack plate to the bridge. Tape one end to the jack plate and push the other end into the bridge somewhere so it can make an electrical contact. What happens?

Jetsam1 said:

Putting any pressure on the tone control crates a static sound so wondering if maybe there is a problem there?

It would be normal to hear static noises when touching the metal casings of pots or the connectors, but only hearing this when you PRESS on the back of a pot is not normal. I assume the underside of the scratchplate has metal foil on the area that sits over the control cavity. If there is no single length of wire bridging the casings of the volume and two tone controls, then the assumption is that the electrical ground connection is being made by the fact that the three potentiometers should all be making metal to metal contact with the foil and creating a shared ground connection that way. The foil can be unreliable. Is the hex nut for the tone knob loose?

[EDIT] Ignore the above. You have a TELEcaster. I was wiring a STRATOcaster shortly before I posted that nonsense.

ICBM · April 17

Jetsam1 said:

OK, took everything apart that I could find. Don't see any separate wires attached to the body, three wires going to each pickup. I tightened the jack socket and have restrung it.

After this the hum/static noise had got quieter. An interesting thing is that taking the tone control all the way down gets rid of all hum and bringing it back up after half way it comes back as per the normal sound. Putting any pressure on the tone control crates a static sound so wondering if maybe there is a problem there?

Just to be clear, I assume this is buzz and not hum. (They’re different.)

The buzz stopping when you touch grounded metalwork, or turning the volume or tone right down, indicates a lack of shielding, or a bad connection between ground and the shielding.

I’ve never seen a modern-spec Fender without shielding paint - it’s been used since the mid-80s on everything other than vintage reissues. The ground terminal may be under the bridge pickup in a Telecaster.

Funkfingers · April 17

Jetsam1 said:

OK, took everything apart that I could find. Don't see any separate wires attached to the body, three wires going to each pickup.

On Fender guitars of that era, it was conventional to run black insulated single core wire from a central lug washer. Separate wires ran to the bridge, the bridge pickup cavity floor, the neck pickup cavity floor and, sometimes, the wiring tunnel between the neck pickup and the control cavity. As ICBM already mentioned, the lug is screwed into the floor of the control cavity. Some Telecasters have a raised section in the cavity floor expressly for this purpose.

Jetsam1 · April 18

Fairly new strings on so not wanting to damage them but I had the bridge off and couldn't see any extra wires or lugs or anything screwed into the cavity. This was an FSR for the year.

I am considering changing out the pickups for more vintage style types and that would be getting done at a techs alongside a general check up. The hiss is not too intrusive through the actual amp.

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Telecaster Hum issue with Amp modeller and amp.

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