Wanna get rid of that buzz and hum?...

rodos1979 · Post by **rodos1979** » Wed May 28, 2003 6:29 pm

Hello to all!

The Holy Spirit has enlighten me again! Well, I just had an idea suddenly as I was watching the TV! I dont know how and why it came to my mind! Well, maybe what I am going to tell is common knowledge to most of you, but to me it was a revelation!

All my cables in my home studio are unbalanced. Furthermore, it is a mess!... mains cables together with audio cables all over the place! I just had this idea to enwrap aluminium foil over all my audio cables. Guess what? At least 10db of noise reduction!!! No hum! No buzz! As if everthing was balanced! ...only con, than they look a bit ugly now...

Anyone with some knowledge on physics? Why is this happening?

Grok · Post by **Grok** » Wed May 28, 2003 6:48 pm

Well it's not a bad idea you had, what you've done is adding a new shielding against electromagnetic fields on your cables.

It's not the same thing as if they were balanced. They always are unbalanced.

There are some tips on how avoiding electromagnetic pollution from AC cables to audio cables...

Immanuel · Post by **Immanuel** » Wed May 28, 2003 7:20 pm

Where Grok?
Thanks Rhodos - I will check out your trick.

Grok · Post by **Grok** » Wed May 28, 2003 8:26 pm

Uh...I don't know where!

Must I give some here?

rodos1979 · Post by **rodos1979** » Wed May 28, 2003 8:30 pm

@Grok: I know that they are still not balanced cables... because no matter if they dont hum or buzz anymore they dont run as 'hot' as balanced cables... it is just that I didnt know that an aluminium foil could work as a shield... this is what impressed me! Anyway, could you point us to where we could find more info on avoiding electromangetic interference with our cables?
@Immanuel: enwrap the cable 2-3 times with aluminium foil and make sure it is tight. Then put a piece of selotape to the joints of the various pieces of aluminium foil so, that everything stays in place and doesnt unfold. It will be a little bit more difficult to bent cables afterwards, but you will notice the difference!

Do it especially with stationary cables that you dont plug/unplug all the time... like the cables that you connect your mixer to Pulsar (this is what I ve done)...

BTW, does anybody knows any trick to avoid the buzz from Strat single coils when you go near the PC monitor? Maybe Grok?

P.S. except from replacing them with humbuckers!

[ This Message was edited by: rodos1979 on 2003-05-28 21:34 ]

astroman · Post by **astroman** » Wed May 28, 2003 10:51 pm

the trick with the monitor is fairly simple, though I guess it might be expensive:
put it in a housing of so called 'MU-metal', the stuff used to shield magnetic from speakers near screens. Leave space for airflow.
If your problem occurs when you approach the monitor from the side where the picture is, it doesn't work that good, because metal is not transparent

You might mount a piece of that stuff somewhere between the viewing position and the guitar. It's possibly best to get a pair of ultra-cheap shielded 'computer speakers' and remove the metal to experiment with the pickup. I'm shure you'll dig it

cheers, Tom

Grok · Post by **Grok** » Thu May 29, 2003 12:08 am

You can also try the aluminium foil to replace the MU metal, it'll be cheap

Or stay away from your monitors when you play your guitar, it's a simple solution too

Grok · Post by **Grok** » Thu May 29, 2003 12:09 am

If you find the result of the aluminium foil very ugly, try to do that in an artistic manner...

_________________
Toujours l'Amour!

[ This Message was edited by: Grok on 2003-05-29 01:12 ]

Grok · Post by **Grok** » Thu May 29, 2003 12:12 am

a name to make researches on internet about magnetic phenomenom and shielding: Faraday

mano · Post by **mano** » Thu May 29, 2003 12:43 am

Aren't there cables with decent shielding which would be equivalent? I always read of MOGAMI "GOLD" cables.

You could always get one of those EBTECH "line level shifters" (8 channels in 1U rack) to get all your unbalanced signals balanced, and hot (+4dBu)

Post by **garyb** » Thu May 29, 2003 2:59 am

ground the foil and it should be even better(dangerous if you don't know what you're doing)......

Fede · Post by **Fede** » Thu May 29, 2003 3:57 am

Yes, your trick is a simple example of Faraday effect that is what is used normally for the shield of a cable.
What you have done: you shielded also the cold lead, that is only the first step of what is called "balancing". It works, but your equipment interrupts that shielding thing at the end of each cable with exposed cold lead chassis. You should cover also any device connected, but as astro said

metal isn't transparent.

For the stratocaster: have you removed ground loops made by Fender ignorant electricians?

ciao,
Fede

[ This Message was edited by: Fede on 2003-05-29 05:21 ]

Grok · Post by **Grok** » Thu May 29, 2003 4:45 am

On 2003-05-29 04:57, Fede wrote:
(...)
For the stratocaster: have you removed ground loops made by Fender ignorant electricians?

ciao,
Fede

That's an important point; where can we find informations about this? Thanks Fede

Grok · Post by **Grok** » Thu May 29, 2003 5:55 am

Some tips...

1) use good shielded audio cables

2) always separate audio cables from AC cables

3) If you cannot prevent that an audio cable crosses an AC cable, here what it's best to do:

4) ground loops (buzz); here is a way to avoid them:

_________________
Toujours l'Amour!

[ This Message was edited by: Grok on 2003-05-29 06:56 ]

krizrox · Post by **krizrox** » Thu May 29, 2003 6:54 am

Whatever works...

Actually, if you check around, you might be able to find some inexpensive AV cable. I found some great stuff at a local electronics supply store. Oxygen free copper, tight braided ground shield and an extra layer of foil over the braid. This isn't the kind of cable you'd use for live sound because the inner foil will split and crack if flexed too much. But it makes great audio cable for permanent installations. Anything of video quality is usually excellent for audio.

Also, look into Canare quad-star balanced mic cable. There are actually 4 conductors for the pos/neg connections (soldered to each connector pin as a twisted pair). This design further reduces noise. Plus you can get it in many different colors which makes ID a breeze.

Grok · Post by **Grok** » Thu May 29, 2003 7:02 am

On 2003-05-29 06:55, Grok wrote:
(...)
4) ground loops (buzz); here is a way to avoid them:

Uh!...This third image is right when using balanced audio cables (with their three connectors; one for the cold point, one for the hot point and one for the ground; you can cut the one for the ground on one side of the cable).

With unbalanced audio cables, if a ground loop is found, you can try to reinforce the ground connection (of the concerned audio unbalanced cables) with a high section electric cable (6mm²) or change the device's place to shorter its ground circuit. Sometimes balancing the faulty audio unbalanced cable is necessary, with a passive transfo or a buffer.

Some may cut the ground on the AC cable of the faulty device; it works but it is against security rules.

_________________
Toujours l'Amour!

[ This Message was edited by: Grok on 2003-05-29 08:18 ]

rodos1979 · Post by **rodos1979** » Thu May 29, 2003 7:43 am

Hello to all!

This is starting to become an exciting topic, at least for me! ;
@astro: since metal isnt transparent, I guess I could overcome this with buying a pair of X-Ray glasses!

@Grok: going away from the monitor when I record is a solution, but it is not practical at all

I will have a search for the faraday thing you mention! Thank you!

On 2003-05-29 03:59, garyb wrote:
ground the foil and it should be even better(dangerous if you don't know what you're doing)......

Tell me a bit more about this plz! I have a shielded cable, which I have never used and it supposed to be used only for grounding purposes. Here in Greece our mains sockets have 2 holes and there are 2 metal things above and below, which are for grounding (this type of mains is called Suko here... it is the type of socket most European countries use). So if I 'tie' one side of the cable to the metal thing on the mains socket and the other side to the aluminium foil, will that improve things further? Could there be any issue with this approach? Please enlighten me!

@Fede: No I have not touched at all the el. guitar inside. I am afraid to do it.. Would it be worth doing it? Or is it better to buy some Seymour Duncan single coil humbucker pickups?

@Grok: I did a search on the net and I found this: http://www.guitarnuts.com/wiring/menu.html It seems promising, but I dont dare to open and fiddle with the electronics in my guitar....yet!

Thanks a lot for the pics too. Unfortunately, for me it is not possible to place them in at a 90o angle cause they are all over the place (since they are longer than they ought to be!...) I want to ask you something that has to do with the last pic. You suggest to cut the ground on the cable. Does this apply only to balanced cables? Unbalanced cables dont have a ground, do they? From that, I can draw the conclusion that one can encounter ground problems/loops only with balanced cables... on the other hand, unbalanced cables suffer only from electromagnetic interference, is that right?

I did not read this chapter in Physics back in school...I thought I would never need such a knowledge... what an idiot!...

@Krizrox: the RCA cables I use where intented for video use... after enwraping them with foil, they got even better sounding! I ll check the cable u suggest. Thank you!

Grok · Post by **Grok** » Thu May 29, 2003 8:19 am

(...)
You suggest to cut the ground on the cable. Does this apply only to balanced cables?

Yes

Unbalanced cables dont have a ground, do they?

They have,too. With unbalanced cables, the ground is merged with the cold point

From that, I can draw the conclusion that one can encounter ground problems/loops only with balanced cables...

Sure!...The issue comes from one connected device

on the other hand, unbalanced cables suffer only from electromagnetic interference, is that right?

Not only; as the grounding issue comes from a device, all kind of grounded cables connected to this device are included in the ground loop

Unfortunately, for me it is not possible to place them in at a 90o angle cause they are all over the place (since they are longer than they ought to be!...)

You have to do that only at a point where they crosses; then make a good separation between them after this point. With a 90° angle, the AC cable does not influence the electric current of the audio cable...

Thanks for the guitar link!

Cheers,
Grok

rodos1979 · Post by **rodos1979** » Thu May 29, 2003 8:51 am

Thank you Grok for all the info!

Mmm...I am thinking now to do another thing... since my PC case is almost empty (the only cards I have are 2 Pulsar2 cards), I am thinking to separate them with aluminium foil somewhow, at least from the AGP card....I am not sure how am I going to do that...I will think a bit about it... Is there any dangerous hidden issue when doing such a thing?

...have you seen the movie My Big Fat Greek Wedding? Do you remeber the father of the bride? For him the cure of all diseases was that glass-cleaning spray... I have found mine!

Fede · Post by **Fede** » Thu May 29, 2003 9:14 am

- also unbalanced suffers from ground loops in the same way (and much more) as balanced. The difference is that with unbal. you cannot stop the ground loop: you should cut the ground but you cannot without opening the circuit!

- Guitar Nuts is a very good site for that problem, see what is told under "Quieting the beast". I didn't try all projects out there, but it's already three years I removed my loops from my strato and I can confirm it is really better. Most lutists (what's the translation for liutaio?) don't understand much of electronics, so you can expect to find anything inside a guitar. First time I read that thing of the loops was some years ago on a GuitarClub number.

- about pickups: if you like singlecoil sound there are a lot of humbucking stacked doublecoil emulating single coil (Kingman, Fender Noiseless, DiMarzio HS3 (Malmsteen), Seymour Duncan...), but imho they all tend to sound like parallel coils. I decided for Fender Lace Sensor as they seemed to me the closest to normal single coils (they aren't doublecoil).

"Enjoy the silence"
Fede

[ This Message was edited by: Fede on 2003-05-30 04:34 ]