earthing!!!!!!!!!!

[Szyderca]

Hi,

I think u should look at residents picture but earth only at "ONE" point to ur chassis and the second thing is... ur main transformer is he screwed directly to the chassis because u can better use some rubber rings between the transformer and the chassis so they will absorbe the 50Hz from the main trafo so it wount be shaiking ur OTP no more and reduce the hummmm in ur speakers !

Greetz Lukasz

[resident]

the second thing is... ur main transformer is he screwed directly to the chassis because u can better use some rubber rings between the transformer and the chassis so they will absorbe the 50Hz from the main trafo so it wount be shaiking ur OTP no more and reduce the hummmm in ur speakers !

I use some rubber rings at the power and at the OPTs,too!
But they're not too thick.Maybe I'll use two of them at each point.

Do you agree with my pic?My next movement is to build it like this.

[Szyderca]

Hi,

I don't agree with the picture for one reason ! I told u it and Sponge Bob to ONLY ONE EARTH and u use two ! U have to remove the main earth from the chassis and connect it with the other earth !

Greetz Lukasz

[resident]

I agree with you!!!
But, do you like my schem????
I can use only one ground!Tomorrow morning I'll try it!
Hope everything gonna be ok!

ONLY ONE EARTH!But at the center of the chassis.I think you agree with it!

[SHiFTY]

I would definitely connect the chassis to ground for reasons of safety. If you have to, use a 100 ohm resistor instead of the capacitor. You really don't want a chassis to be many volts above ground.

Safety First!

[Family_Dog]

Hi Resident,

You have already received some excellent advice from other members of this forum. Here is something else for you to consider:

Does your 6V filament winding on your mains transformer have a centre-tap to earth, (i.e. three wires, 3.15 - 0 - 3.15 Volts), or are there only two wires from the LT supply (i.e. 0 - 6.3V)? If there is a centre tap winding, ensure it is, in fact, earthed. If there are only two wires, then take two 100-ohm resistors and connect them in series across the 6.3v winding. Then earth the centre point of the two resistors to your single chassis earth.

Please note that this is only to be used for your amplifier tubes and NOT the tube rectifier filaments if you're using a tube rectifier.

-Eric

[EC8010]

Originally posted by Szyderca
U have to remove the main earth from the chassis and connect it with the other earth!

SAFETY! Never, ever, remove the mains earth from the chassis! If you have a hum loop because of two earth connections, break the connection between the signal earth and the chassis, NEVER the mains earth. We don't want people missing from the forum because of an electrical accident.

[resident]

Star earth is ready. I use only one chassis earth point with 100R resistor.
Things become too much better!!
BUT I still have a little.
With grounded inputs you must place your ear very close to speaker to hear it. With open inputs I have more and in one channel is louder. Why?
I’m sure, my hum becomes from power transformer. I’m placing my ear on it and I hear the same thing on my speakers. I put some rubber rings but it remains audible. Do you believe it’s my winders fault or all big EI-core transformers have this noise? ( It’s rated at 560W )
I don’t know if this is normal. So, please tell me, do you have this little hum, too? From listeners place everything is ok. But at late hours it’s audible.
For an experiment I pull out the input tube and phase splitter to see what I’ll hear and hum went dramatically out. You don’t hear anything. It’s sooo little that I love it. This means that my problem is on wiring?

[resident]

I can't do anything with my hum problem



I have done anything I can.I'm thinking ( damn it ) to rebuild the amp.
What I didn't do?

[SY]

Your idea of radiated hum pickup may be correct. If I read your drawing correctly, you have the filament/heater leads crossing the input leads?