"active grounding" - why would one use it?

[jarthel]

I searched the forums and the basic concept has been explained.

I'm just wondering why would one use it. lots of amps doesn't have it so it's not a requirement to enjoy wonderful sound.

thank you for the replies

[janneman]

Active grounding? Couldn't find it on the forum. What is that? What posts did you find?

Jan Didden

[-_nando-_]

I think that it's used when you don't have a split supply, and you want the ground as a mid reference. Something like, you have a car with 12v battery, and you want to deal with opamps, then you decide to work with -6v 0 and +6v instead 0 - 12v, creating a mid reference (used as ground) of a half of the power supply, so 6v.

[jarthel]

Originally posted by janneman
Active grounding? Couldn't find it on the forum. What is that? What posts did you find?

Jan Didden

my apologies. I should have use the words "active ground" and it would return a lot of replies.

I'm searching for the thread that describe it but having no luck yet.

anyway, here's what a designer of headphone amps has to say:
===========
The designer (Ti Kan) of the Beta22 described it as follows:

A 3-channel "active ground" amplifier is the recommended configuration for standard 3-wire headphones. The ground channel amplifier sources or sinks the return current from the transducers, which would otherwise have been dumped into signal ground or power supply ground in a 2-channel amp. This shifts responsibility for the high current reactive load of the headphones from signal ground to the tightly regulated power supply rails, thus removing the primary source of signal ground contamination. The headphone transducer "sees" symmetrical output buffers with equal impedance and transfer characteristics on both sides, rather than an amplifier on one side and a capacitor bank of the power supply ground on the other. This results in lower output impedance, greater linearity and reduced stereo crosstalk.

=========================

in the design, you have PCBs for right/left channel. And then another PCB for the ground (same pcb as right/left channels except that the input is connected to signal ground).

the 1st image may give a better idea: http://www.amb.org/audio/epsilon22/

[Juergen Knoop]

does not make sense to me...

[jneutron]

Originally posted by janneman
Active grounding? Couldn't find it on the forum. What is that? What posts did you find?

Jan Didden

YOU!!!YOU!!YOU!!

What the H##L do you think you are doing, baiting me like that.


YOU KNOW...DON'T DENY IT....

I see that tube opamp...you knew I was refurbing a systron donner 3400, didn't ya.

Is that thing in your hands, or did you find the pic?

Cheers, John

[AndrewT]

Originally posted by juergenk
does not make sense to me...

Originally posted by jneutron


YOU!!!YOU!!YOU!!

What the H##L do you think you are doing, baiting me like that.


YOU KNOW...DON'T DENY IT....

I see that tube opamp...you knew I was refurbing a systron donner 3400, didn't ya.

Is that thing in your hands, or did you find the pic?

Cheers, John

I'm just like Juergenk.
John,
what is that all about?

[sam9]

You might want to look at Project 43 at
http://sound.westhost.com

[tade]

Let me help sam9 here as it wasn't worth his time:
http://sound.westhost.com/project43.htm

[jarthel]

Originally posted by sam9
You might want to look at Project 43 at
http://sound.westhost.com

if you look at the link I posted, it's not as simple as that.

The accompanying power supply (same website but look for sigma22 (sigma in greek letter)) for left/right channels already has +/- supplies.