Transnova Circuit

[hitsware]

>No, the way the concept works is that
>it makes the stage wotk in common
>source, i.e. it has gain, this is why it's
>sources are grounded and the power
>supply is floating.

OK but still it will without the op-amp, right ?

 

[ilimzn]

>The output stage works in common
>source, i.e. it has gain, this is why it's
>sources are grounded and the power
>supply is floating.

OK but still it will without the op-amp, right ?

Yes, of course, but to get it working properly you will have to add some 'housekeeping' around the circuit to ensure proper centering of the power supply (In essence, this is actually the output stage offset voltage, although it's not entirely correct to call it that since the output is AC coupled.
It is of course possible to replace the single power supply with a dual/center-tapped one, and connect it's + and - ends just like the one shown in the schematic, while the center tap would go directly to the output. The 4700uF caps will not be needed then (of course, they could be part of the power supply filtering) and the circuit becomes DC coupled. You would then need a means to set the output offset voltage.

 

[lineup]

Sakis,
--------------------------
Anyway check out QSC amp schemas.
Link
Check "Discontinued Models / Series One

interesting schematics
Like this one, Andy
QSC Series One 1080

 

[mlloyd1]

why not just clone the "real" transnova concept from it's inventor.
links here and here

mlloyd1

 

[lineup]

that one looks better, mlloyd
as it uses only discretes

thanks

 

[rtarbell]

If this trans-nova concept is used in an amp design, and thus the output stage is a common emitter-type with gain greater than 1, then what is the power supply rejection of this output stage?

For example, if the floating supplies had small 120Hz hum on them, would this configuration be able to reject the hum just as well as a conventional darlington or triple darlington common collector output stage with the same 120Hz hum on its ground referenced power supplies?

 

[lineup]

Generally I would say
common emitter output have much lower PSRR, power supply rejection ratio.
This is when output is taken from the collectors/drains of output transistors.

But this is not the only factor to determine the level of PSRR.
The driver stages before plays their part, too.