Monolithic SuperSymmetry with Current Feedback

[jh6you]

I post scope pictures again, after arrangement of few pF (twisted lines) parallel with R2 and R4.

The scope and oscillator are connected as shown below.

JH

 

[jh6you]

Sign wave at 1k Hz (1v/div x10). This wave is just before symmetric clipping.

JH

 

[jh6you]

Square wave at 1k Hz.

JH

 

[jh6you]

Square wave at 40Hz.

JH

 

[jh6you]

Sign wave at 100k Hz.

JH

 

[jh6you]

square wave at 100k Hz.

JH

 

[jh6you]

JH

 

[Netlist]

Looks very decent to me, still we don't know which load you connected?
On your first sine wave 1V/div X10 you have about 9Vpp.
On the mosfet versions I have 10Vpp.
I will post some squarewaves of it later, input compared with output.

/Hugo - Wonders if this amp can be made a Class-A one?

 

[jh6you]

I will post some squarewaves of it later, input compared with output.

It would much appreciate if you post a brief sketch how the load, scope and oscillator are set.
Thanks.

JH

 

[Netlist]

It would much appreciate if you post a brief sketch how the load, scope and oscillator are set.
Thanks.

JH

Your scope and sinegenerator a correctly connected in your sketch.
The load, of course should be connected between +Out & -Out.
(Speaker 8 or 4ohm).

In the following pictures you'll see the input and output compared to each other.
The lowest squarewave is the input.
Input 20mV/div; Output 100mV/div. Sweep time depending on frequentie.
Here's one of 40Hz.
As you can see, my generator is rather crappie, but it's the difference between in and out who is important.

/Hugo

 

[Netlist]

Square 4Khz

 

[Netlist]

Square 100Khz

These are not taken at full output, but with 130mV input signal.

 

[grataku]

jh6you, great job getting this baby to work! I am eagerly awaiting your comments on the sound.

so what happened in post #355 is completely gone by putting a few pf in the x fdbck??
Is everythink well behaved at 20-50kHz?

 

[jh6you]

8 ohm load resistor connected.

All are at 4k Hz.

(1) Directly from the signal generator (0.1 v/div, probe x10)
(2) Output (0.5 v/div, probe x10)
(3) Directly from the signal generator
(4) Output

Here is (1).

 

[jh6you]

(2)

 

[jh6you]

(3)

 

[jh6you]

(4)

 

[jh6you]

completely gone by putting a few pf in the x fdbck??
Is everythink well behaved at 20-50kHz?

Yes, it looks so.
Yes, it looks so.

Sure will post the sound impression.

JH

 

[Bernhard]

If we use mosfets, on the gate resistors will drop 5V if we are lucky, which means we can use rails of 20V ( 20-5=15 ) and get more power, right

 

[Netlist]

If we use mosfets, on the gate resistors will drop 5V if we are lucky, which means we can use rails of 20V ( 20-5=15 ) and get more power, right

Bernhard,
Assuming you are talking about post #300 with, of course additional Gate resistors (220ohm)
I get the following values:
gate resistors 560ohm
Source resistors 0.47ohm
V = +/-18V
Total current dissipation before clipping: 1.8A with sinewave 400Hz
12Vpp on the scope.
Don't ask me to calculate the RMS power at 8 or 4ohm...
That's what I measured on the amp that’s currently running
I guess we might increase the voltage to 20V. Power dissipation will be 12Watt per mosfet with gate resistors of 580ohm.

/Hugo