Tech: 'Need earthed'

Subject: 'Need earthed'
From: Pete
Date: 10 Apr 99 - 05:11 PM

I've just recently had a bridge pick-up put in my bouzouki and it makes an annoying buzzing sound untill I touch the jack-pin surround. I dont know much about the electrics in instruments as I'm basically an acoustic player but need to get the thing sounding right. Any suggestions? Thanks

Pete

Subject: RE: 'Need earthed'
From: Joe Offer
Date: 10 Apr 99 - 10:01 PM

Hi, Pete - you have some terms in there we in the U.S. wouldn't quite understand (even though there are those among us who attempt to be cosmpolitan by adding extraneous European vowels, as in "humour"). I don't often talk electricity with 220-volt people. first step is to make sure that everything is properly grounded and shielded - I take it "earthed" is what we refer to as "grounded."
I'm wondering what sort of grounding is used for electronic equipment outside the U.S. We use two-prong plugs that are polarized so they can be inserted in only one direction; or three-prong plugs with a round prong for the ground and flat ones for the other two wires.
I have no idea what you use for microphone cables. Standard guitar mikes in the U.S. use a round, 1/4-inch plug.
this doesn't give you much of an answer, but maybe it will keep the thread alive so you do get an answer. Maybe it will also help me learn a bit about how things are wired outside the U.S. In the meantime, click here for an interesting FAQ that may help you learn a bit about microphones.
-Joe Offer-

Subject: RE: 'Need earthed'
From: Alex
Date: 13 Apr 99 - 12:01 AM

If your bouzouki is the type with a metal tailpiece where all the strings attach, he easiest way to get rid of the hum is to run a wire from the tailpiece to the nut on the jack socket so when you touch the strings you are the ground. It will still hum when you let go the strings. If the pick-up is one of the ones you install under the bridge saddle and you installed it yourself, it is very important to have both the bottom of the saddle and the bottom of the saddle recess absolutely flat so that the pick-up is crimped equally all along its length between the saddle and the top of the instrument. If not, you will get weird results and uneven reproduction of sound freqencies. As another approach, try plugging it into a Direct Box which has a Ground (earth) Lifter before sending the signal to the amp. DBs are expensive - take it to a music store and see if it works first.

Subject: RE: 'Need earthed'
From: katlaughing
Date: 13 Apr 99 - 12:04 AM

I once had an English Ford Cortina. I loved opening the hood and seeing the mechanics' faces when they'd see the sticker about the ground wire. It just said "to earth".

Subject: RE: 'Need earthed'
From: Alex
Date: 13 Apr 99 - 12:10 AM

Kat, technically, your Cortina wasn't really earthed. They (Ford) used the chassis as the negative side of a DC electrical system. You had to put one of those little chain things dangling down from the rear bumper to earth it properly. Now go to your room - you're grounded.

Subject: RE: 'Need earthed'
From: mountain tyme
Date: 13 Apr 99 - 12:50 AM

Should read....they used the chassis as the positive side of the DC electrical system. The earth was the high ground! This method of polarity cancells the formation of rust. Very few USA mfgrs. use this to our advantage. Most USA mfgrs. use the opposite polarity to their own advantage. With the bouzouki when you touch the jack pin which is high (and should not be), your body acting as a big capacitor is earthing it and cancelling the AC hummmm. Somewhere along the way your connection is open. To test this theory play the bouzouki in your bare feet when standing on wet ground. You will probably feel the leaking electricity traveling thru your body indicating a poorly made or installed pickup. Have someone ready to pull the plug when you try this. A better/safer method is to hold one probe of a voltmeter in your hand and then touch the jack pin with the other probe (you will feel nothing). If you get a volt reading your earth is open/broken/missing and you will never be able to play your bouzouki while on holliday at an outing on the beach. Cheers!

Subject: RE: 'Need earthed'
From: Alex
Date: 14 Apr 99 - 10:15 PM

Well, MY Cortina rusted out pretty fast and failed its MOT.

Subject: RE: 'Need earthed'
From: katlaughing
Date: 15 Apr 99 - 12:14 AM

Alex, I might be "grounded" but I can still fly!*smile*

kaltaughingHAO

Subject: RE: 'Need earthed'
From: Alex
Date: 16 Apr 99 - 01:39 AM

Well, ya gotta smoke 'em if ya got 'em!

Subject: RE: 'Need earthed'
From: mountain tyme
Date: 16 Apr 99 - 02:05 AM

Well Alex you might just check with them record book folks cause you might have had the only Cortina that did anything fast. As for Pete, you might just have a bum wire. Also your pickup probably terminates thru a high Z cord. A high Z adaptor to low Z has a transformer in it and sometimes solves AC hum problems. If you are plugging into a mixing board you would also have the advantage of some preamping with low Z. The direct box idea is a good one that will also give you AC line isolation. When you "fly" down to the store to try one also try a Rolls or ART MP preamp using low Z connections thruout. These can also be used as direct boxes and provide additional preamp beyond a direct box and cost less.

Subject: RE: 'Need earthed'
From: Alex
Date: 17 Apr 99 - 01:11 AM

That Cortina was a MK 1 and it was in an extremely unattractive shade of Ford Shitty Bown that matched the rust spots perfectly. The previous owner had put "Go-faster" stripes down both sides which created the optical illusion that it was speedily rusting before your eyes! The preamp idea is a good one. Again, go to your music store and try it out. Practice repeating the phrase, "Yes, but do you have anything cheaper?" An alternative approach is to check out Audio-Technica's Digital Reference line. I have a DR-G95 acoustic guitar condenser mic, It has a spring clip, mini-gooseneck and mic designed to clamp inside the instrument on to an internal brace of a guitar. You mount it pointing to the rear of the guitar and if you want to get real loud, you can put one of those rubber bungs in the sound hole. The cable hangs out of the soundhole rather like the srting on a a tampon and it is difficult to convert to an end-socket-strap-plug because although it is a 2-wire high-Z from amp to the instrument, it has asmall box containing the batteries and a volume control which goes to a 4-wire cable to the mic. For about $120 it may solve all your problems.

Subject: RE: 'Need earthed'
From: LEJ
Date: 17 Apr 99 - 02:09 AM

And what time is it when two Cortinas collide?

Tin to tin

Subject: RE: 'Need earthed'
From: katlaughing
Date: 17 Apr 99 - 10:17 AM

Mine was a light shade of monkey vomit green!