Hi,
Tried to search but didn't find anything useful..so:
If u had to have an external powersupply,which one would u prefer:
1. only trafo and sending AC to the amp and do all regulating/filtering/rectifying there..or
2. complete dc-supply and just some additional filtering at the amp..
And my other q,....
Is there any real benefits to use a virtual ground other than that it's practical and preferable in battery-driven amps, but soundwise, does it makes things better?
Thanx guy's!
__________________
Peder
Tried to search but didn't find anything useful..so:
If u had to have an external powersupply,which one would u prefer:
1. only trafo and sending AC to the amp and do all regulating/filtering/rectifying there..or
2. complete dc-supply and just some additional filtering at the amp..
And my other q,....
Is there any real benefits to use a virtual ground other than that it's practical and preferable in battery-driven amps, but soundwise, does it makes things better?
Thanx guy's!
__________________
Peder
From my experience – it’s the best possible solution: transformer on the outside and everything else inside. I’ve tried it with several versions of my preamp and it worked like a charm. This way, power supply – its regulator parts are as close as possible to consumer circuits, shielded by the enclosure itself. Nowadays, this is the only way I’m building my preamplifiers. As far as the power amplifiers are concerned, I’m doing them classical way – everything inside. No experiences with virtual ground, though.
There is a few specifics to be pondered when considering a virtual ground. First of all, how are you achieving your virtual ground. Are you using one power supply that has only + and -?
Using two resistors from +V to -V and creating a voltage divider to get a "ground" that is in the middle of the +V and -V? If this is the case, the virtual ground or 'floating ground' is a legitamate way to create a symetrical power supply. The only problem is that this is only a virtual ground, not a hard ground. This virtual ground will function wonderfully as a reference point, but not as a current source, as a hard ground would be. If you are making Op-amp circuits and occilators this idea will work well. You can't connect the speaker to it or get much current though. You should consider making a +V, ground, -V supply for this.
The real problem with mounting power transformers inside case with the circuit is the magnetic noise. This is really a problem if you are using any audio transformers in your circuit. The problem with mounting it outside is the length of wire running from the secondary to the amp and may require filtering inside and a thicker guage wire to handle the current spikes without the wire causing a voltage drop.
Using two resistors from +V to -V and creating a voltage divider to get a "ground" that is in the middle of the +V and -V? If this is the case, the virtual ground or 'floating ground' is a legitamate way to create a symetrical power supply. The only problem is that this is only a virtual ground, not a hard ground. This virtual ground will function wonderfully as a reference point, but not as a current source, as a hard ground would be. If you are making Op-amp circuits and occilators this idea will work well. You can't connect the speaker to it or get much current though. You should consider making a +V, ground, -V supply for this.
The real problem with mounting power transformers inside case with the circuit is the magnetic noise. This is really a problem if you are using any audio transformers in your circuit. The problem with mounting it outside is the length of wire running from the secondary to the amp and may require filtering inside and a thicker guage wire to handle the current spikes without the wire causing a voltage drop.
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