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Just how noisy are high-gains supposed to be?
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Author:  johnallg [ Tue Aug 01, 2006 7:47 am ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

You could also make a full shield with copper foil all inside the pot and pickup cavities including the underside of the pickguard. I did that with just aluminium duct tape and eliminated all single coil noise unless I am really close to a TV, computer display, or the trannies in my amp. Make sure it is grounded in one place to the circuit ground.

Author:  Beatlefreak [ Tue Aug 01, 2006 8:38 am ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

You shouldn't have to shield the entire cavity against noise. We're talking audio frequencies here, not RF.

Atoz - do both of your pickups produce the hum/noise? In ohter words, if you select one or the other pickup, is the noise eliminated, or at least reduced?

Author:  Atoz [ Sun Aug 06, 2006 10:30 pm ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

Quote:
You shouldn't have to shield the entire cavity against noise. We're talking audio frequencies here, not RF.

Atoz - do both of your pickups produce the hum/noise? In ohter words, if you select one or the other pickup, is the noise eliminated, or at least reduced?


Sorry for appearing to abandon the thread. My basement flooded on the 1st, and I've been a bit busy. Fortunately, my 4003 was one of the few surviving items!

Both pickups hum, the bridge pickup a bit more than the neck pickup. I generally run both pickups, and I don't really have a place to plug in at the moment, so I can't tell you if switching between pickups changes anything. I should have my house in order in the next few days, so I can try that out.

johnallg - I had thought about shielding the cavity- J-bass owners do it all the time- but I hadn't heard anything in regard to the necessity of doing it on Rics. Based on your experience, it sounds like it's worth a shot.

Author:  Rickboy88 [ Mon Aug 07, 2006 10:01 am ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

For what it is worth, I compared my two Rics (4001S and 4003) against my other basses (old Hagstroms and new Rogue) and didn't hear where the hum was any worse than the others. I thought the 4003 could have even been a bit more quiet. I know at least one of the Hagtroms is single coil.
I used my new Fender Rumble 100 and one of the Ric-O-Sound cables.

Author:  Rickboy88 [ Mon Aug 07, 2006 10:14 am ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

Quote:
You shouldn't have to shield the entire cavity against noise. We're talking audio frequencies here, not RF.


Just some general info here. Even though the 60 Hz hum (and harmonics) is a lower frequency than radio frequency noise, it is still an electromagnetic signal, so shielding techniques are still valid. Submarines talk to each other with very low frequency (ELF) radio signals as that is the only thing that gets through the water.

Something to try as an experiment is to touch your finger to the tip of the patch cable from the amp and then get your hand close to a lamp (especially metal on the lamp). You'll hear the hum really ratchet up. Touch the lamp metal and you better have your gain turned down.

johnallg's technique is a valid one. You want to create a "Faraday cage" around the pickups and wiring as much as possible - referenced to a single ground point. If he's seen a reduction that means it works (honest).

Author:  johnallg [ Mon Aug 07, 2006 10:34 am ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

Quote:
johnallg's technique is a valid one. You want to create a "Faraday cage" around the pickups and wiring as much as possible - referenced to a single ground point. If he's seen a reduction that means it works (honest).


The point to remember and strive for is two-fold. You have to make a "cage" as Rickboy88 stated, and you also need the one-point ground. Of course the pickup openings will not be shielded, and will allow hum and noise in that direction (right in the front of the bass). I used to pick up the flyback of my 32" tv through the wall and about 6-7 feet away. Not now, unless I am really close and facing it.

You also need a really good guitar cable, 100% shielded, for this to work good. I make my own. Using Canare star-quad mic cable that has 4 wires and a full braiding (blue for signal, white for ground, shield only grounded at one end) I still get a fair amount of noise besides losing noticable high frequency content, due to capacitance. I thought with the gread braiding it would be superior - wrong. Using Canare instrument cable (GS-6) I achieve the quieting of the noise except very close to the front of the pickups (no shielding in that direction). I also got the higher frequencies amount and clarity back.

http://www.canare.com/index.cfm?objecti ... 4EA6821ADA

Author:  Atoz [ Mon Aug 07, 2006 12:28 pm ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

Quote:
Quote:
johnallg's technique is a valid one. You want to create a "Faraday cage" around the pickups and wiring as much as possible - referenced to a single ground point. If he's seen a reduction that means it works (honest).


The point to remember and strive for is two-fold. You have to make a "cage" as Rickboy88 stated, and you also need the one-point ground. Of course the pickup openings will not be shielded, and will allow hum and noise in that direction (right in the front of the bass). I used to pick up the flyback of my 32" tv through the wall and about 6-7 feet away. Not now, unless I am really close and facing it.

You also need a really good guitar cable, 100% shielded, for this to work good. I make my own. Using Canare star-quad mic cable that has 4 wires and a full braiding (blue for signal, white for ground, shield only grounded at one end) I still get a fair amount of noise besides losing noticable high frequency content, due to capacitance. I thought with the gread braiding it would be superior - wrong. Using Canare instrument cable (GS-6) I achieve the quieting of the noise except very close to the front of the pickups (no shielding in that direction). I also got the higher frequencies amount and clarity back.

http://www.canare.com/index.cfm?objecti ... 4EA6821ADA


Very informative! I would like to try this cavity shielding/cable construction. I do have a question:

What was the reason for aluminum duct tape for the pickup cavities over copper tape? Availability? Cost? I would think that copper tape would more easily allow soldering seams, etc.




Author:  Fooll [ Tue Aug 08, 2006 9:47 am ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

I have found that when I use the outlets in the main house I have the hum.. ( Aluminum wiring ). Plugged into the room addition there's no hum.. ( Copper wiring ).



Author:  johnallg [ Tue Aug 08, 2006 10:35 am ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

Quote:
Very informative! I would like to try this cavity shielding/cable construction. I do have a question:

What was the reason for aluminum duct tape for the pickup cavities over copper tape? Availability? Cost? I would think that copper tape would more easily allow soldering seams, etc.


Thanks!

Totally because of availability. I had just had a new furnace put in a couple years earlier and they left me a roll of the tape! :D Copper would be better for the ability to solder the edges and joints together. The aluminium doesn't solder.

Oh, I also ran an inch wide strip from the metal on the neck pickup to the cavity metal, and from the shield wire under the bridge pickup wiring to the metal surround and cavity metal. Just remembered that.

Author:  Atoz [ Tue Aug 08, 2006 12:14 pm ]
Post subject:  Re: Just how noisy are high-gains supposed to be?

I'm going to give the shielding thing a go. I think I can get Cu tape from stewmac.

Fooll brings up an interesting observation with regard to Al vs. Cu wiring. I live in an older house where the room I'm using was rewired in the early 80s. That was during the era of widespread Al wiring use. Hmmm...

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