center tap (0 Volts) on the secondarys of your transformer to a chip amp?
so you would not connect it with the regular star ground.
It creates a floating (transformer)ground.
This seems to work and also sounds pretty good actually!
I seems this has not been discussed.
I dont know if there are any negatives about this?
The ground level could be lifted by any ground offset of the source i think.
I have a cheap DVD player i was working on that gave problems (Audible popping) but i havent figured out whats going on yet. Theres a TV close by that seems to interfear. Two other sources were fine though
CO
so you would not connect it with the regular star ground.
It creates a floating (transformer)ground.
This seems to work and also sounds pretty good actually!
I seems this has not been discussed.
I dont know if there are any negatives about this?
The ground level could be lifted by any ground offset of the source i think.
I have a cheap DVD player i was working on that gave problems (Audible popping) but i havent figured out whats going on yet. Theres a TV close by that seems to interfear. Two other sources were fine though
CO
Ground impedance and dirty earth...
Thanks for the info guys.......................
I found out that my amp drifted away 6V from the center tap bij removing it from there due to assymetrical loading. This does make me think about the impedance of the ground which is too high i geuss to be able to cause this by only drawing a watt or two bias current.
My wiring isnt top notch but i do have a propper "star" ground.
Anyone have an idea how to do this without connecting center tap of transformer?
I was thinking of hammering a metal ground rod into the earth for as earth. Is this possible? and will the ground be cleaner than my regular very dirty earth??
CO
Thanks for the info guys.......................
I found out that my amp drifted away 6V from the center tap bij removing it from there due to assymetrical loading. This does make me think about the impedance of the ground which is too high i geuss to be able to cause this by only drawing a watt or two bias current.
My wiring isnt top notch but i do have a propper "star" ground.
Anyone have an idea how to do this without connecting center tap of transformer?
I was thinking of hammering a metal ground rod into the earth for as earth. Is this possible? and will the ground be cleaner than my regular very dirty earth??
CO
The "earth" ground will be very clean, on one condition--that you NEVER EVER EVER use it in the same equipment as a regular ground. If you do, the ground loop mains hum will probably be louder than your actual signal!!
If you want to go straight to earth, though, a cold water pipe is probably a better idea; the conductivity will probably be better. I remember when I was a little 8-year old boy scout and the scoutmasters were teaching us how to go swimming on inflated levis in water below freezing and at the same time (the memories are vauge but I do remember some things for sure) remembering to hook our little AM radios up to a cold water pipe for good grounding, but to always have a 1-zillion ohm resistor between us and ground so if we touch something with lots of voltage it doesn't kill us.
Like I said. It's vague. But try a cold water pipe. You might like it.
If you want to go straight to earth, though, a cold water pipe is probably a better idea; the conductivity will probably be better. I remember when I was a little 8-year old boy scout and the scoutmasters were teaching us how to go swimming on inflated levis in water below freezing and at the same time (the memories are vauge but I do remember some things for sure) remembering to hook our little AM radios up to a cold water pipe for good grounding, but to always have a 1-zillion ohm resistor between us and ground so if we touch something with lots of voltage it doesn't kill us.
Like I said. It's vague. But try a cold water pipe. You might like it.
Re: Much cleaner
How is it any cleaner than a proper star ground node? As per Kirchhoff, the sum of the currents at any given node is zero. As for low impedance, low impedance compared to what? How can a long length of wire running off to a ground rod or water pipe have a lower impedance than the short runs of wire in the circuit going to the star ground node?
se
Coolin said:
How is it any cleaner than a proper star ground node? As per Kirchhoff, the sum of the currents at any given node is zero. As for low impedance, low impedance compared to what? How can a long length of wire running off to a ground rod or water pipe have a lower impedance than the short runs of wire in the circuit going to the star ground node?
se
Re: Re: Much cleaner
the 0 volt of the transformer is floating between the two phases of the secondairy so i think you can imagine it will not be the most rock steady reference we would like.
It isnt a very low impedance for the amp when you disconnect it from the star ground. Thats why i got an offset.
I think the improvement in sound also comes from a reduction of mains noise going through the transformer directly to 0V
CO
We might just get a thread going.
/not a bad theory for someone who's very new to electronics.
I can just see those electrons flowing....
Steve Eddy said:
the 0 volt of the transformer is floating between the two phases of the secondairy so i think you can imagine it will not be the most rock steady reference we would like.
It isnt a very low impedance for the amp when you disconnect it from the star ground. Thats why i got an offset.
I think the improvement in sound also comes from a reduction of mains noise going through the transformer directly to 0V
CO
We might just get a thread going.
/not a bad theory for someone who's very new to electronics.
I can just see those electrons flowing....
Steve
Likewise
I haven't had chance to dig out the plots yet, as my other half was not well at the weekend, which left me somewhat busier than expected.
W.r.t. the earth think RF, think shielding, think non-linearity, think impedance beyond DC.
The ability of an audio system to maintain linearity in the presence of RF is a difficult thing to achieve, particularly in high gain, low noise app's (e.g. MC phono).
It's almost impossible to design a circuit to reject common mode RF signals that performs optimally at AF, hence shielding is the only solution that can prevent them getting there in the first place.
Mains earth can have a high RF impedance, depending upon how it is supplied, hence a good local earth (which may have higher impedance at DC than the mains earth) can be a massive benefit.
You can hear it if you try.
Andy.
Likewise
I haven't had chance to dig out the plots yet, as my other half was not well at the weekend, which left me somewhat busier than expected.
W.r.t. the earth think RF, think shielding, think non-linearity, think impedance beyond DC.
The ability of an audio system to maintain linearity in the presence of RF is a difficult thing to achieve, particularly in high gain, low noise app's (e.g. MC phono).
It's almost impossible to design a circuit to reject common mode RF signals that performs optimally at AF, hence shielding is the only solution that can prevent them getting there in the first place.
Mains earth can have a high RF impedance, depending upon how it is supplied, hence a good local earth (which may have higher impedance at DC than the mains earth) can be a massive benefit.
You can hear it if you try.
Andy.
linearity in the presence of RF
You are absolutely right. The concept of ground is grossly oversimplified. I have worked on telecom boards with transient, analog, digital, negative 48 volt return, and ESD grounding strategies on the same two layer board! I went to an Analog Devices seminar where they discussed the effect of RF on non linearities in instrumentation amplifiers. RF can even cause DC shifts in circuits.
It is amazing how someone with a limited grasp of engineering priciples thinks he knows so much. If such people would read some electronic theory outside of basic audio design they would find out about all kinds of things that audio engineers overlook that can be important. The effect of RF is one of the most important factors and is usually overlooked by most audio designers. I could post some links but I am tired of force feeding people who would rather argue than learn.
You are absolutely right. The concept of ground is grossly oversimplified. I have worked on telecom boards with transient, analog, digital, negative 48 volt return, and ESD grounding strategies on the same two layer board! I went to an Analog Devices seminar where they discussed the effect of RF on non linearities in instrumentation amplifiers. RF can even cause DC shifts in circuits.
It is amazing how someone with a limited grasp of engineering priciples thinks he knows so much. If such people would read some electronic theory outside of basic audio design they would find out about all kinds of things that audio engineers overlook that can be important. The effect of RF is one of the most important factors and is usually overlooked by most audio designers. I could post some links but I am tired of force feeding people who would rather argue than learn.
Good christ Steve, NO OFFENSE but you remind me of one of those f'n pre-meds that would argue the last 1/2 point to go from an A+ to an A++.
Yes, Steven dear, you are right again. Your mother must have told you that a lot. I remember the "brain fart" episode that you had a while ago. Your only defense was to remind Fred he had a similar episode maybe three years ago. Let me break it down for you...nobody cares.
Yes, Steven dear, you are right again. Your mother must have told you that a lot. I remember the "brain fart" episode that you had a while ago. Your only defense was to remind Fred he had a similar episode maybe three years ago. Let me break it down for you...nobody cares.
Coolin said:
I'm not sure if I get correct picture here. You are using centertapped secondaries, but don't connect centertap. Isn't it the same as using single secondary with twice the voltage?
If you want to get rid of floating centertap, why not use some resistors and by conecting them between rails and centertap, obtain the refference and still not using the ground?
grataku said:
This isn't about any last half point.
It's about whether an actual earth ground has any particular relevance to audio equipment or not.
My reminding Fred of his similar episode (which was two months ago, not three years) was no defense of my own. The reminder was wholly a response to his rather snide "Amateurs..." remark.
It was simply saying that if overlooking something which in hindsight should have been obvious makes one an amateur, then I was in good company with Fred.
Had he not made such a remark, I would have said nothing more than to acknowledge my own error.
No one cares about what? Getting at the truth?
se
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