Shielding a Starfire?

lungimsam

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My NS Starfire is a little noisy. Nothing bad but I would like to get it silent, or as close to silent as poss when not playing but still keep volume open all the way.

I have successfully silenced my solid body basses but never did this on semi-holla's before.
I was wondering if anyone had any clues.
I want to play it at church but I want to quiet it down first.
 

Mr. Lumbergh

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Gibson hollows used to have grounded "shielding cans" that contained the pots, but I did have a hard time finding any. I cleaned up my Gretsch Electro a lot when I rewired it using a small-gauge coax cable for the wiring, Belden 20AWG I picked up from Antique Electronic Supply if I remember correctly.
 

fronobulax

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No idea. I don't expect working inside will be easy.

FWIW, I insisted on practicing in a room with a traditional dimmer switch, next to a room with a microwave and a wireless landline, above a washing machine that for some bizarre reason put out a lot of RF and with my cell phone in my pocket. Somewhat to my surprise the level of noise was acceptable and I found that by rolling off the volume to about 7 much of the noise went away. This was true for both my '67 and my Newark Street so I figure it may be the price you pay for having a "full spectrum" pickup. On the other hand the Betts Bass (solid) which has a Novak BSDS and is shielded is pretty close to noiseless so maybe shielding will help.

I do see you want to play wide open. That is your preference, but I did find when doing things like trying to play Bach my sound was actually cleaner by backing off on the volume.
 

Nuuska

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Hello

If it is only disturbing between songs - why not use volume pedal?
 

Happy Face

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That makes sense, but it is one extra piece of gear to forget to bring along and a couple of extra cords that will break and whatever.

The OP's church venue is a little more difficult than a bar with a neon Bud sign next to the florescent-laden jukebox, both of which are on the same circuit as the fussy amp you plug your single coil Ricky into. Unless that bar is a biker bar where pulling the plug on the jukebox, much less the neon, might be construed as an aggressive act. Right, Dan?
 

Nuuska

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Hello


1. You could do a little experiment - take a good size sheet of tinfoil - cover entire back of your bass with it - maybe even wrap it around sides - make sure it is connected to ground. If this makes the difference you are wishing for, then we know it works and can start figuring how to get that foil inside.


2. If the guitar cable is long, there might sometimes be difference, if instead of regular cord ( hot + shield ) you use a cable that is made of high quality microphone cable.

Connection in guitar end mono plug
- red to tip
- black to ground
- shield OFF - make sure it is isolated

Connection in amp end mono plug
- red to tip
- black to ground
- shield to ground

The idea is, that signal does not travel in the shield, that picks up noise

Guitar pickups among phono pickups are symmetrical by construction. Both are relatively high impedance + low voltage devices. I can not imagine why these were not wired balanced ( hot + cold + shield ) to amp .

Now this gives me an idea of how to make the bass quieter ( the first cup of coffee in this morning starts to wake me up . . .)

3. If the pickup / -s of your bass have signal wires PLUS separated ground wire - then you could use stereo output jack. Wire the output from pots to tip and ring. Wire the pickup shield, pot shields + bridge to ground. The pots likely have the shields connected to ground end of pot - so that must be separated.

Now if we use this with regular cable, everything is electrically as before.

But if you use a cable with mono plug in amp end wired
- red to tip
- black to ground
- shield to ground
And STEREO plug in guitar end wired
- red to tip
- black to ring
- shield to ground

This isolates signal path totally from ground, that is now connected to your strings, pu-covers and pot covers. They get together at amp input.

This modification is low budget - one stereo jack plus one cable - and some tinkering. And if it does not bring the results that were expected, there is no need to reverse it, since it will work with regular guitar cord.


And while we are at it - the quality of cable - with balanced line level low impedance pro equipment the shield is not that critical. But as the signal levels go down and impedances go up and signal goes unbalanced, the importance of proper shield becomes more obvious. Some guitar cords use a shield, that is like a net - wires crossing each other - leaving 80% of the area empty. The best cables have two layers of tight copper shield wrapped in opposite directions - some have even a thin plastic layer in between to keep those two from rubbing each other.


Example of low q cable https://www.thomann.de/fi/the_sssnake_ik22.htm
Example of good cable https://www.thomann.de/fi/sommer_cable_galileo_238_plussw.htm

Before whining how expensive the good cable will be - we must think, that the guitar/bass + amp surely deserve something of equal level.
And good cable deserves good connectors - I use Neutrik

By now I had second cup of coffee - fried egg and delicious sandwiches - sun is shining - temp is about 22C/72F - perhaps time for https://www.youtube.com/watch?v=D9mSPFw7BXo
 

Nuuska

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Hello

Had a nice day walking the dog - washing windows and doing some gardening.

Then I thought I draw a schematic to add to my previous post - but started to think - certainly someone else must have done this before - and found this:

thumb.php


It is on this webpage - https://naiant.com/guitar-wiring/


The Starfire can be wired like I proposed - no real need for dual potentiometers, since the circuit is "floating". Also no need for X-former, unless wanted. Besides in above picture the transformer adds extra load on pickup even in "OFF" position, while the primary is permanently connected.
 
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