Hiss or hum?

[_sky_]

Hello,


Probably this was debated but I didn´t find what I was looking for. So...what´s the difference between Hiss and Hum?

A friend of my has 3 basses and two of them make noise when not touching the strings, jack or other metal part. One of these makes more noise but it have active pickups.

The other one has a noise when leveling up the tone control for the neck pickup. Thouching any metal part won´t do the trick.

Yes all basses are single coil. In on of them, a Fender P-Bass, he was shielded the cavities with cooper foil.

I´ve shield one of my two basses and I´ve noticed the Hum (believe was hum) decreased.

Cheers

 

[DiabolusInMusic]

The hum that goes away when you touch metal is RF interference, that can be remedied with a proper shielding job. The hum that remains constant, since it is on single coils it is probably 60hz hum. Is it a jazz style bass? Does the hum stop when both pickups are balanced? The one with active pickups probably has passive pickups and an active pre-amp.

Here is my shielding guide, it should help with your issue. If you have any more questions feel free to PM me (or quote me in this thread) and I will be glad to help.

http://www.talkbass.com/threads/so-your-bass-has-a-hum.1079579/

The difference between "hiss" and "hum" is mostly definition. RF interference could easily be described as either and has been in my experience. On TB, RF causes hum, but in the real world I have always heard it called "the Fender hiss."

 

[1958Bassman]

Hiss is fairly random noise, like when you're between stations on a radio and hum has a definite frequency. Buzz has a definite frequency, but it's higher than hum. Touching the tip of an instrument cable when the other end is in the amplifier's jack cause a noise that can be called 'hum' or 'buzz', but it's not hiss. Gain in a circuit causes hiss when it's not picking up lower frequency interference of fixed frequency but it's not only the circuit, it can be a noisy device like transistors, old carbon composition resistors, op-amps, etc.

 

[_sky_]

The hum that goes away when you touch metal is RF interference, that can be remedied with a proper shielding job. The hum that remains constant, since it is on single coils it is probably 60hz hum. Is it a jazz style bass? Does the hum stop when both pickups are balanced? The one with active pickups probably has passive pickups and an active pre-amp.

Here is my shielding guide, it should help with your issue. If you have any more questions feel free to PM me (or quote me in this thread) and I will be glad to help.

http://www.talkbass.com/threads/so-your-bass-has-a-hum.1079579/

The difference between "hiss" and "hum" is mostly definition. RF interference could easily be described as either and has been in my experience. On TB, RF causes hum, but in the real world I have always heard it called "the Fender hiss."

Nice! Thanks. Just one question. What is the better (and probably only way) to shield the pickup? I mean, you have to curl the copper tape over the pickup or just leave it?

 

[DiabolusInMusic]

Nice! Thanks. Just one question. What is the better (and probably only way) to shield the pickup? I mean, you have to curl the copper tape over the pickup or just leave it?

In the guide you can see how I do it. I add foil to the insides of the cover. I ground the cover by bringing it over the screw holes and allowing the screws to pierce the body and pickup cover shielding. It can also be done by leaving a lip of copper over the pickup cover and soldering a wire directly to the cover, this is what I used to do but it requires adding 1 or 2 extra wires.

Do not touch the pickup with copper! If needed, put electrical tape around the windings but you should be able to get by without, just take care.

 

[_sky_]

In the guide you can see how I do it. I add foil to the insides of the cover. I ground the cover by bringing it over the screw holes and allowing the screws to pierce the body and pickup cover shielding. It can also be done by leaving a lip of copper over the pickup cover and soldering a wire directly to the cover, this is what I used to do but it requires adding 1 or 2 extra wires.

Do not touch the pickup with copper! If needed, put electrical tape around the windings but you should be able to get by without, just take care.

I will. Thanks!

 

[_sky_]

The hum that goes away when you touch metal is RF interference, that can be remedied with a proper shielding job. The hum that remains constant, since it is on single coils it is probably 60hz hum. Is it a jazz style bass? Does the hum stop when both pickups are balanced? The one with active pickups probably has passive pickups and an active pre-amp.

Here is my shielding guide, it should help with your issue. If you have any more questions feel free to PM me (or quote me in this thread) and I will be glad to help.

http://www.talkbass.com/threads/so-your-bass-has-a-hum.1079579/

The difference between "hiss" and "hum" is mostly definition. RF interference could easily be described as either and has been in my experience. On TB, RF causes hum, but in the real world I have always heard it called "the Fender hiss."

I remembered one thing. In my bass I have a little hum and will use copper tape on it but I have a small detail. Between the Bass/Control Cavity and the metal plate I have an acrylic plate (in photo). The best way to ensure the connection between the plate and the cooper tape is a wire between the metal plate and the copper tape in the controlo cavity I supose. Do you think it´s the best option?

 

[DiabolusInMusic]

What is that acrylic plate like on the bottom? Is it just a ring? If it is a ring I would just wrap foil around it so it touches the metal plate above it.

 

[_sky_]

What is that acrylic plate like on the bottom? Is it just a ring? If it is a ring I would just wrap foil around it so it touches the metal plate above it.

It is an acrylic ring. I have a led that lights up everytime I push the knob near the jack input (Active mode). The Acrylic is just to show a light. I suppose I can wrap a small part of the acrylic ring.

 

[DiabolusInMusic]

You don't need to wrap it around the outside of the ring, just the inside so it can make contact with the metal plate. This will ground the metal plate as well, since it is metal it doesn't require any shielding. It should not affect the ring's appearance.

 

[_sky_]

You don't need to wrap it around the outside of the ring, just the inside so it can make contact with the metal plate. This will ground the metal plate as well, since it is metal it doesn't require any shielding. It should not affect the ring's appearance.

I explained poorly. Yes I will wrap it inside.