How to removing the ******* HUM sound from our GC??

[thomgun_lc]

Actually, we don't focusing in HUM sound. When the HUM sound not audible, we forget that problem.
Many people said that we must use toroidal trafo's, star grounding techique but i think, that's technique only reduce hum sound not removing HUM sound.
If we look another branded amplifier, in their output sound don't contain any HUM sound, how they do that??
Do i need to build ground loop breaker??
Any idea?
If we can remove this HUM sound, ur GC sound become more professional,

[12 Cents]

Did you swear in the subject line?

Maybe you can describe your exact problem a little better...

[peranders]

Hum is normally not a problem and has nothing to do with using a toroid or not. If you do things right you will get a hum free amp.

[alexw88]

There is an excellent paper from Jensen about hum:

http://www.jensen-transformers.com/apps_wp.html

Take a look at their AN004 - Hum & Buzz in Unbalanced Interconnect Systems (94KB PDF)

From my experience, if you have hum with your amp's input disconnected, then it comes from your amp.

If you only have hum when you connect your amp to the source, then the hum comes from the current flow in the shield of the interconnect.

[12 Cents]

That's right, short out the inputs and hear what happens. Make sure the signal lines in the amp are not in direct neighborhood to the transformer.

[wes-ninja250]

> Many people said that we must use toroidal trafo's, star grounding techique but i think,
> that's technique only reduce hum sound not removing HUM sound.

Amplifiers don't by nature hum. They amplify electrical signals. If there is an unwanted hum in the signal, the amplifier with amplify it.

So, the trick has nothing to do with reducing or removing hum, the trick is simply to not introduce any hum.

Toroidal transformers help because their electromagnetic field is well-contained. EI transformers have a larger external magnetic field, which is also quite directional. If you pass a wire through a magnetic field, that field causes electrons in the wire to move -- introducing hum. So, using a toroid, you don't have to worry as much about routing your wires.

Another source of hum is current travelling through your ground wires -- grounds will be at slightly different potentials due to the imperfect nature (non-zero resistance) of non-superconducting wire. So, we use star ground technique so that the ground potentials are all the same.

Remember: don't introduce hum into your amp, and it won't hum.

Wes

[Treefingers]

i have no hum from my amp.

I have used a star ground for the signel, and a star ground for the power, then linked both to earth via a (i think it is a zobel) .22uf, 100Ohm

[thomgun_lc]

Actually,I use El transformer, and i know about flux magnetic which can induced to GC cable. But i still, hear a 50Hz hum sound in my GC although the Hum sound is very low. But, i still hear if my ear close to the loudspeaker (about 10cm), without any input of course.
It's not audible when i sit about 1 metre from my loudspeaker.
The HUM sound is not bother me but i want my GC free from Hum sound, so our GC become more professional
I'm sure all of the DIYers has the HUM problem, although the HUM is not audible/very low but almost of them tolerated this problem .
If the branded amplifier can remove the HUM, why we can't?
Toroidal and El are not the main reason in producing HUM sound because i know that many branded amplifier using El transformator, and they don't produce any HUM sound.So, we can remove the HUM sound although we use El transformator. But, it need a some technique.

[Greg Erskine]

Originally posted by thomgun_lc
[BI'm sure all of the DIYers has the HUM problem, although the HUM is not audible/very low but almost of them tolerated this problem [/B]

My GC has no hum, zero, zilch, even with my ear stuck in the speakers so the side of my head touches the cone and the volume turned up.

I have had hum in one or two GCs but has has always turned out to be an issue with earthing or cables.

Regards

[wes-ninja250]

Why are you sure all DIYers have hum?

If the hum is not audible, there is not hum. This applies to store-bought and DIY amps. There is no magic difference between the two.

Your problem is either wiring or ground. Find the source of your hum, and you can eliminate it. Why not post a picture of your amp? Somebody may be able to help.

Wes