This headphone amplifier is based on the Tori amplifier, which name seems to come from an agressive dog.
I hope to have tamed that dog, hence the name 'Snuggles', Simulating the amplifier in LTspice was not easy for me to get right. I probably should have called this amp 'Struggles' instead of 'Snuggles'.
Anyway, I am planning to build it using a NE5532 or similar, but what do you think? Does it have a chance of success?
I hope to have tamed that dog, hence the name 'Snuggles', Simulating the amplifier in LTspice was not easy for me to get right. I probably should have called this amp 'Struggles' instead of 'Snuggles'.
Anyway, I am planning to build it using a NE5532 or similar, but what do you think? Does it have a chance of success?
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It looks workable
Not sure R3 does much tbh and R1 (and using a resistor is fine) could perhaps be improved with a simple transistor current sink instead. As the amp is AC coupled the DC balance is not so important but would be an issue if you converted it to a dual rail supply.
Not sure R3 does much tbh and R1 (and using a resistor is fine) could perhaps be improved with a simple transistor current sink instead. As the amp is AC coupled the DC balance is not so important but would be an issue if you converted it to a dual rail supply.
Hi Mooly, thanks for your quick reply.
R3 actually did the trick to make it work in LTSpice, but like you I am not sure why it is needed. I will not be surprised if it will just work without it, like the original Tori amp did.
My space here is limited and I only have a single rail supply. That is why I made it AC coupled. Apart from I do not hear the difference anyway
R3 actually did the trick to make it work in LTSpice, but like you I am not sure why it is needed. I will not be surprised if it will just work without it, like the original Tori amp did.
My space here is limited and I only have a single rail supply. That is why I made it AC coupled. Apart from I do not hear the difference anyway
That sim is not behaving as expected...
Try an LT1056A opamp (it is like a TL072) and a 2N2222 model for the transistor. Add a cap in the feedback return.
R1 is not allowing enough current into the load on negative half cycles. Reduce the value or add a current sink.
Try an LT1056A opamp (it is like a TL072) and a 2N2222 model for the transistor. Add a cap in the feedback return.
R1 is not allowing enough current into the load on negative half cycles. Reduce the value or add a current sink.
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The harmonics this causes may sound interesting and if so I will make that 'shortcut' switchable, if it does not cause oscillation.taking the output transistor out of the feedback loop
The harmonics this causes may sound interesting and if so I will make that 'shortcut' switchable, if it does not cause oscillation.
That's a good idea. I can't see any stability issues with a design like this.
You can also use an LED for the current sink which saves a transistor. Resistor value depends on the LED colour (different colours have different forward volt drops)
If you make the signal caps '1' in the sim (1 Farad) it effectively takes the time constants out of the sim and you will see a more accurate FFT.
Which is also a good idea!You can also use an LED for the current sink which saves a transistor. Resistor value depends on the LED colour (different colours have different forward volt drops)
And I thought the .asc file was corrupted I learn a lot Mooly!If you make the signal caps '1' in the sim (1 Farad) it effectively takes the time constants out of the sim and you will see a more accurate FFT.
Finally, after some virtual experimentation I decided I will build the following circuit, output transistor switchable inside and outside the feedback loop, using a LM317 as a constant current source.
I expect the switch between Q1 inside and outside the feedback loop to be interesting, soundwise.
Q1 outside the feedback loop:
Q1 inside the feedback loop:
I expect the switch between Q1 inside and outside the feedback loop to be interesting, soundwise.
Q1 outside the feedback loop:
Q1 inside the feedback loop:
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