The 1kHz is the main wanted output and the other 'spikes' are the unwanted harmonics.
I just spotted that you haven't put a '1' in the voltage source which is normally done when running an AC Analysis. How to explain... this sets the input as '1' or 0db with other points you measure referenced to this. If you make it '2' and look at the input signal as an AC Analysis (frequency response like below) then it will be +6db and not 0db and so on.
The distortion looks OK 🙂
Without:
With:
I just spotted that you haven't put a '1' in the voltage source which is normally done when running an AC Analysis. How to explain... this sets the input as '1' or 0db with other points you measure referenced to this. If you make it '2' and look at the input signal as an AC Analysis (frequency response like below) then it will be +6db and not 0db and so on.
The distortion looks OK 🙂
Without:
With:
i decided to remove some capacitors and i realised that i could also remove one transistor, but there still is some work to do such us getting the dc operating point as low as possible and as stable as possible, and upgrading the input stage which should benefit the overall amplifier performance.
Things to look at.
Have you measure the DC offset?
1/ Removing the feedback return cap sees a problem with DC offset. I would always retain a cap here.
2/ R3 and R16 are far to low in value. These only need supply base current for the current sources.
3/ R11 only serves to introduce supply noise and to make the offset dependent on supply voltage.
Have you measure the DC offset?
1/ Removing the feedback return cap sees a problem with DC offset. I would always retain a cap here.
2/ R3 and R16 are far to low in value. These only need supply base current for the current sources.
3/ R11 only serves to introduce supply noise and to make the offset dependent on supply voltage.
You would not normally introduce anything here as it is the point negative feedback is applied.
There are quite a few things I would look at really. Q2 is struggling for gain given the high Class A bias currents you want and so are the individual TIP42's.
I'm not really sure how far you can go with this basic configuration really 🙂
There are quite a few things I would look at really. Q2 is struggling for gain given the high Class A bias currents you want and so are the individual TIP42's.
I'm not really sure how far you can go with this basic configuration really 🙂
Not necessarily but it does need quite a lot more work and thinking through to get a viable design 🙂
or just make an class ab amplifier becuse i realised the biggest transformer i have is like a 100va 2x20V and that transformers are expensive
Well it is a starting point you could develop I suppose....
I've lots of sims for different amps if you want any. This could be an interesting one, its one I built from years ago and it was really good as I recall. You could look at altering it from a single rail to a split rail and it should suit your transformer voltages well.
This should click and run as it uses default models:
That kind of seals the deal but it would make a nice small amp.
I've lots of sims for different amps if you want any. This could be an interesting one, its one I built from years ago and it was really good as I recall. You could look at altering it from a single rail to a split rail and it should suit your transformer voltages well.
This should click and run as it uses default models:
why bother when things like jat501 exist with proper output stages and what not. i think with few basic changes i could adapt it to a smaller supply voltage
Quasi stages have a following, reputed to sound good whatever the technical shortcomings may be.
This is a Rotel which is not unlike the one you were experimenting with. You will to sort the models out like with the other one 🙂
This is a Rotel which is not unlike the one you were experimenting with. You will to sort the models out like with the other one 🙂
I would recommend adding a small resistor (10-50ohm) to the Q3 emitter. In this case, you need to increase the resistance R1R9. But it is better to use Schottky diodes instead. You can see how to do this in my Hyperbolic AB amplifier project