Discrete Super Symmetric(I think) Opamp for I/V Etc...

[PigletsDad]

I suppose I should add that I assume that Nelson's patent applies to my circuit as well, in those territories where the patent has been granted.

It was certainly designed with Nelson's ideas very firmly in mind, as the simplest discrete circuit I could think of that gave DC accuracy and the supersymmetry principle.

[Russ White]

Here is the circuit as I am laying it out now.

It has short circuit and SOA protection.

It is thermally stable thanks to the CFP output.

The distortion should be very very very low.

The PDF is of the simulation, reference designators and such are not finalized.

It is a simulation of the circuit in I/V mode with filter caps for a Fc of about 200khz.

The circuit as shown would work with PCm1794A and output 2VRMS peak output.

Cheers!
Russ

[Russ White]

here are the simulated THD number into the 300R/300pf load:

The first is the balanced THD, The second is the THD of a single output to GND.

Heightened Def Con from 0.000256019 to 0.000256019
Fourier components of V(out+,out-)
DC component:8.29446e-010

Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 2.000e+04 2.770e+00 1.000e+00 -5.68° 0.00°
2 4.000e+04 7.463e-10 2.694e-10 -20.80° -15.12°
3 6.000e+04 5.798e-08 2.093e-08 69.54° 75.23°
4 8.000e+04 7.130e-10 2.574e-10 -126.70° -121.01°
5 1.000e+05 1.230e-08 4.440e-09 149.26° 154.95°
6 1.200e+05 1.214e-09 4.382e-10 -63.77° -58.09°
7 1.400e+05 8.478e-09 3.061e-09 -50.92° -45.24°
8 1.600e+05 1.409e-09 5.087e-10 50.66° 56.34°
9 1.800e+05 3.645e-09 1.316e-09 -29.03° -23.35°
Total Harmonic Distortion: 0.000002%


Fourier components of V(out+)
DC component:-0.000220695

Harmonic Frequency Fourier Normalized Phase Normalized
Number [Hz] Component Component [degree] Phase [deg]
1 2.000e+04 1.385e+00 1.000e+00 -5.68° 0.00°
2 4.000e+04 6.406e-07 4.626e-07 -15.68° -9.99°
3 6.000e+04 2.908e-08 2.100e-08 70.81° 76.49°
4 8.000e+04 1.410e-09 1.018e-09 139.62° 145.31°
5 1.000e+05 5.837e-09 4.215e-09 152.53° 158.21°
6 1.200e+05 1.175e-09 8.487e-10 -79.13° -73.44°
7 1.400e+05 4.244e-09 3.064e-09 -43.23° -37.55°
8 1.600e+05 1.138e-09 8.217e-10 14.40° 20.09°
9 1.800e+05 1.647e-09 1.190e-09 -40.27° -34.58°
Total Harmonic Distortion: 0.000046%

[Russ White]

20 khz, same load

Green trace is balanced output.

Blue is SE.

[ejaouen]

Are these discrete balanced I/V (and LPF) stages going to be available soon ?
From your trials of these : are they worth it over THS4131 opamps IVY stages ?

I will place an order of COD modules and wonder if discrete balanced I/V stage is coming.
thanks in advance

[Russ White]

Originally posted by ejaouen
Are these discrete balanced I/V (and LPF) stages going to be available soon ?
From your trials of these : are they worth it over THS4131 opamps IVY stages ?

I will place an order of COD modules and wonder if discrete balanced I/V stage is coming.
thanks in advance

Hello,

Yes they are coming at some point. We just have a lot to do right now.

Measurement wise I doubt it will be much if any better than the THS4131, it may actually not be quite as good, but it will have more load current capacity, and it is discrete which will make some people happy.

I will have one measured and report when the project is finished.

Cheers!
Russ

[Blitz]

Hi Russ, very nice indeed...any progress on this one ?

[Russ White]

Thanks Blitz,

I am testing a proof of concept output stage which I plan on applying to this circuit as well. If that goes well then I will proceed with this amplifier.

Thanks for your interest.

Cheers!
Russ