+/- 28V 3A supply

[andRookie]

Could I make my supply for a 40W stereo powr amp running in class A like this drawing, with a "floating ground".

[Mooly]

In theory yes... in practice it's perhaps not the best approach. If the amp has any points internally that connect to "ground" where a DC current flows or is sourced, then this will unbalance the "ground" with respect to the other rails.

Ultimately the "ground" is your chosen reference and an absolute, but it's what it does with the repect to the other rails that might be an issue

You could... use an NPN/PNP pair to make a sort of active ground, still with the large caps.

What's the amp anyway ?

[AndrewT]

Originally Posted by andRookie

40W stereo power amp running in class A

500VA and 40+40W of ClassA does not sound quite right. I think your 500VA will be run right at it's limit delivering this power.

Each channel will need ~ 1.6A of bias to give 40W of ClassA into 8r0.

Total bias for two channels is 3.2A continuous from the PSU.

[bobodioulasso]

Yes it works.
I used it for an F5.
The problem is , fo a class A amp, the total capacitor is divided by two. So tou have to add another big one across the vhole voltage.

[andRookie]

Originally Posted by Mooly

What's the amp anyway ?

It is an old gb150d module I bought second hand.

[andRookie]

Originally Posted by AndrewT

I think your 500VA will be run right at it's limit delivering this power.

I actually have two of them. Just made the schem for simplicity.

[Mooly]

Originally Posted by andRookie

It is an old gb150d module I bought second hand.

Thank you... not familiar with it.

[andRookie]

Originally Posted by Mooly

You could... use an NPN/PNP pair to make a sort of active ground, still with the large caps.

What kind of transistors are suiteble for that "active ground" job?

[bobodioulasso]

In the Quad 606, they use ztx652/ztx752
I used bd139/140, no heatsinks.

[andRookie]

Ok, thanks.
I´ll try to make a schematic so maybe you guys can look through it.