GainWire mk4 fully balanced line amp

[dadod]

GainWire mk4 fully balanced line amp from the input to the output with no GNFB.
Quite low distortion, excellent CMRR, very low nose(fixed signal noise ratio at all volume sets).
Schematic, Gain, CMRR
Damir

 

[dadod]

FFT.

 

[dadod]

Noise.

 

[dadod]

I hopped for some comments and suggestion here, but nothing.
It is first time I do fully balanced pre amp. The idea was to use GainWire mk2 as starting point. That pre amp can work as NGNFB and as it is a current conveyor there is possibility to put the volume pot at the current conveyor output instead input and with it get a big advantage of a fixed signal/noise ratio independent of the volume pot setting.
Now there I had idea to use only single volume pot for the balanced volume regulation, but that sims is not so good idea. Distortion is higher then if double volume pot with the middle grounded is used. Distortion specially goes up at low volume settings.
Attached the simulations to show that


edit: second picture should, of course, the volume pot of 4k to have the same gain, but still it shows the idea.

 

[SteveWang]

So it's basically a gainware mk2+gainware mk2?

 

[dadod]

So it's basically a gainware mk2+gainware mk2?

Yes, but only in NGNFB, no CFA. A volume pot is after input gain stage and output buffer and it change the gain of the input stage.